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1275 |
phoenix |
/*
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* scsi_lib.c Copyright (C) 1999 Eric Youngdale
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*
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* SCSI queueing library.
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* Initial versions: Eric Youngdale (eric@andante.org).
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* Based upon conversations with large numbers
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* of people at Linux Expo.
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*/
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/*
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* The fundamental purpose of this file is to contain a library of utility
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* routines that can be used by low-level drivers. Ultimately the idea
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* is that there should be a sufficiently rich number of functions that it
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* would be possible for a driver author to fashion a queueing function for
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* a low-level driver if they wished. Note however that this file also
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* contains the "default" versions of these functions, as we don't want to
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* go through and retrofit queueing functions into all 30 some-odd drivers.
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*/
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#define __NO_VERSION__
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/timer.h>
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#include <linux/string.h>
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#include <linux/slab.h>
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#include <linux/ioport.h>
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#include <linux/kernel.h>
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#include <linux/stat.h>
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#include <linux/blk.h>
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#include <linux/interrupt.h>
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#include <linux/delay.h>
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#include <linux/smp_lock.h>
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#include <linux/completion.h>
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#define __KERNEL_SYSCALLS__
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#include <linux/unistd.h>
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#include <asm/system.h>
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#include <asm/irq.h>
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#include <asm/dma.h>
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#include "scsi.h"
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#include "hosts.h"
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#include "constants.h"
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#include <scsi/scsi_ioctl.h>
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/*
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* This entire source file deals with the new queueing code.
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*/
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/*
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* Function: __scsi_insert_special()
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*
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* Purpose: worker for scsi_insert_special_*()
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*
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* Arguments: q - request queue where request should be inserted
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* rq - request to be inserted
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* data - private data
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* at_head - insert request at head or tail of queue
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*
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* Lock status: Assumed that io_request_lock is not held upon entry.
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*
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* Returns: Nothing
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*/
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static void __scsi_insert_special(request_queue_t *q, struct request *rq,
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void *data, int at_head)
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{
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unsigned long flags;
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ASSERT_LOCK(&io_request_lock, 0);
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rq->cmd = SPECIAL;
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rq->special = data;
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rq->q = NULL;
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rq->nr_segments = 0;
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rq->elevator_sequence = 0;
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/*
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* We have the option of inserting the head or the tail of the queue.
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* Typically we use the tail for new ioctls and so forth. We use the
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* head of the queue for things like a QUEUE_FULL message from a
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* device, or a host that is unable to accept a particular command.
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*/
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spin_lock_irqsave(&io_request_lock, flags);
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if (at_head)
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list_add(&rq->queue, &q->queue_head);
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else
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list_add_tail(&rq->queue, &q->queue_head);
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q->request_fn(q);
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spin_unlock_irqrestore(&io_request_lock, flags);
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}
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/*
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* Function: scsi_insert_special_cmd()
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*
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* Purpose: Insert pre-formed command into request queue.
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*
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* Arguments: SCpnt - command that is ready to be queued.
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* at_head - boolean. True if we should insert at head
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* of queue, false if we should insert at tail.
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*
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* Lock status: Assumed that lock is not held upon entry.
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*
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* Returns: Nothing
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*
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* Notes: This function is called from character device and from
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* ioctl types of functions where the caller knows exactly
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* what SCSI command needs to be issued. The idea is that
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* we merely inject the command into the queue (at the head
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* for now), and then call the queue request function to actually
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* process it.
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*/
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int scsi_insert_special_cmd(Scsi_Cmnd * SCpnt, int at_head)
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{
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request_queue_t *q = &SCpnt->device->request_queue;
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__scsi_insert_special(q, &SCpnt->request, SCpnt, at_head);
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return 0;
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}
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/*
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* Function: scsi_insert_special_req()
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*
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* Purpose: Insert pre-formed request into request queue.
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*
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* Arguments: SRpnt - request that is ready to be queued.
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* at_head - boolean. True if we should insert at head
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* of queue, false if we should insert at tail.
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*
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* Lock status: Assumed that lock is not held upon entry.
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*
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* Returns: Nothing
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*
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* Notes: This function is called from character device and from
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* ioctl types of functions where the caller knows exactly
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* what SCSI command needs to be issued. The idea is that
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* we merely inject the command into the queue (at the head
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* for now), and then call the queue request function to actually
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* process it.
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*/
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int scsi_insert_special_req(Scsi_Request * SRpnt, int at_head)
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{
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request_queue_t *q = &SRpnt->sr_device->request_queue;
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__scsi_insert_special(q, &SRpnt->sr_request, SRpnt, at_head);
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return 0;
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}
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/*
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* Function: scsi_init_cmd_errh()
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*
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* Purpose: Initialize SCpnt fields related to error handling.
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*
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* Arguments: SCpnt - command that is ready to be queued.
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*
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* Returns: Nothing
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*
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* Notes: This function has the job of initializing a number of
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* fields related to error handling. Typically this will
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* be called once for each command, as required.
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*/
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int scsi_init_cmd_errh(Scsi_Cmnd * SCpnt)
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{
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ASSERT_LOCK(&io_request_lock, 0);
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SCpnt->owner = SCSI_OWNER_MIDLEVEL;
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SCpnt->reset_chain = NULL;
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SCpnt->serial_number = 0;
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SCpnt->serial_number_at_timeout = 0;
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SCpnt->flags = 0;
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SCpnt->retries = 0;
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SCpnt->abort_reason = 0;
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memset((void *) SCpnt->sense_buffer, 0, sizeof SCpnt->sense_buffer);
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if (SCpnt->cmd_len == 0)
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SCpnt->cmd_len = COMMAND_SIZE(SCpnt->cmnd[0]);
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/*
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* We need saved copies of a number of fields - this is because
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* error handling may need to overwrite these with different values
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* to run different commands, and once error handling is complete,
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* we will need to restore these values prior to running the actual
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* command.
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*/
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SCpnt->old_use_sg = SCpnt->use_sg;
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SCpnt->old_cmd_len = SCpnt->cmd_len;
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SCpnt->sc_old_data_direction = SCpnt->sc_data_direction;
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SCpnt->old_underflow = SCpnt->underflow;
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memcpy((void *) SCpnt->data_cmnd,
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(const void *) SCpnt->cmnd, sizeof(SCpnt->cmnd));
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SCpnt->buffer = SCpnt->request_buffer;
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SCpnt->bufflen = SCpnt->request_bufflen;
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SCpnt->reset_chain = NULL;
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| 204 |
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SCpnt->internal_timeout = NORMAL_TIMEOUT;
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SCpnt->abort_reason = 0;
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| 207 |
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return 1;
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}
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| 209 |
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| 210 |
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/*
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| 211 |
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* Function: scsi_queue_next_request()
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| 212 |
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*
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| 213 |
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* Purpose: Handle post-processing of completed commands.
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| 214 |
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*
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| 215 |
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* Arguments: SCpnt - command that may need to be requeued.
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| 216 |
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*
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| 217 |
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* Returns: Nothing
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| 218 |
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*
|
| 219 |
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* Notes: After command completion, there may be blocks left
|
| 220 |
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* over which weren't finished by the previous command
|
| 221 |
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* this can be for a number of reasons - the main one is
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| 222 |
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* that a medium error occurred, and the sectors after
|
| 223 |
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* the bad block need to be re-read.
|
| 224 |
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*
|
| 225 |
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* If SCpnt is NULL, it means that the previous command
|
| 226 |
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* was completely finished, and we should simply start
|
| 227 |
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* a new command, if possible.
|
| 228 |
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*
|
| 229 |
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* This is where a lot of special case code has begun to
|
| 230 |
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* accumulate. It doesn't really affect readability or
|
| 231 |
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* anything, but it might be considered architecturally
|
| 232 |
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* inelegant. If more of these special cases start to
|
| 233 |
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* accumulate, I am thinking along the lines of implementing
|
| 234 |
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* an atexit() like technology that gets run when commands
|
| 235 |
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* complete. I am not convinced that it is worth the
|
| 236 |
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* added overhead, however. Right now as things stand,
|
| 237 |
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* there are simple conditional checks, and most hosts
|
| 238 |
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* would skip past.
|
| 239 |
|
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*
|
| 240 |
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* Another possible solution would be to tailor different
|
| 241 |
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* handler functions, sort of like what we did in scsi_merge.c.
|
| 242 |
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* This is probably a better solution, but the number of different
|
| 243 |
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* permutations grows as 2**N, and if too many more special cases
|
| 244 |
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* get added, we start to get screwed.
|
| 245 |
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*/
|
| 246 |
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void scsi_queue_next_request(request_queue_t * q, Scsi_Cmnd * SCpnt)
|
| 247 |
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{
|
| 248 |
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int all_clear;
|
| 249 |
|
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unsigned long flags;
|
| 250 |
|
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Scsi_Device *SDpnt;
|
| 251 |
|
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struct Scsi_Host *SHpnt;
|
| 252 |
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|
| 253 |
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ASSERT_LOCK(&io_request_lock, 0);
|
| 254 |
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|
| 255 |
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spin_lock_irqsave(&io_request_lock, flags);
|
| 256 |
|
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if (SCpnt != NULL) {
|
| 257 |
|
|
|
| 258 |
|
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/*
|
| 259 |
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* For some reason, we are not done with this request.
|
| 260 |
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* This happens for I/O errors in the middle of the request,
|
| 261 |
|
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* in which case we need to request the blocks that come after
|
| 262 |
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* the bad sector.
|
| 263 |
|
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*/
|
| 264 |
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SCpnt->request.special = (void *) SCpnt;
|
| 265 |
|
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list_add(&SCpnt->request.queue, &q->queue_head);
|
| 266 |
|
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}
|
| 267 |
|
|
|
| 268 |
|
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/*
|
| 269 |
|
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* Just hit the requeue function for the queue.
|
| 270 |
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*/
|
| 271 |
|
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q->request_fn(q);
|
| 272 |
|
|
|
| 273 |
|
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SDpnt = (Scsi_Device *) q->queuedata;
|
| 274 |
|
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SHpnt = SDpnt->host;
|
| 275 |
|
|
|
| 276 |
|
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/*
|
| 277 |
|
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* If this is a single-lun device, and we are currently finished
|
| 278 |
|
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* with this device, then see if we need to get another device
|
| 279 |
|
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* started. FIXME(eric) - if this function gets too cluttered
|
| 280 |
|
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* with special case code, then spin off separate versions and
|
| 281 |
|
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* use function pointers to pick the right one.
|
| 282 |
|
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*/
|
| 283 |
|
|
if (SDpnt->single_lun
|
| 284 |
|
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&& list_empty(&q->queue_head)
|
| 285 |
|
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&& SDpnt->device_busy == 0) {
|
| 286 |
|
|
request_queue_t *q;
|
| 287 |
|
|
|
| 288 |
|
|
for (SDpnt = SHpnt->host_queue;
|
| 289 |
|
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SDpnt;
|
| 290 |
|
|
SDpnt = SDpnt->next) {
|
| 291 |
|
|
if (((SHpnt->can_queue > 0)
|
| 292 |
|
|
&& (SHpnt->host_busy >= SHpnt->can_queue))
|
| 293 |
|
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|| (SHpnt->host_blocked)
|
| 294 |
|
|
|| (SHpnt->host_self_blocked)
|
| 295 |
|
|
|| (SDpnt->device_blocked)) {
|
| 296 |
|
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break;
|
| 297 |
|
|
}
|
| 298 |
|
|
q = &SDpnt->request_queue;
|
| 299 |
|
|
q->request_fn(q);
|
| 300 |
|
|
}
|
| 301 |
|
|
}
|
| 302 |
|
|
|
| 303 |
|
|
/*
|
| 304 |
|
|
* Now see whether there are other devices on the bus which
|
| 305 |
|
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* might be starved. If so, hit the request function. If we
|
| 306 |
|
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* don't find any, then it is safe to reset the flag. If we
|
| 307 |
|
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* find any device that it is starved, it isn't safe to reset the
|
| 308 |
|
|
* flag as the queue function releases the lock and thus some
|
| 309 |
|
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* other device might have become starved along the way.
|
| 310 |
|
|
*/
|
| 311 |
|
|
all_clear = 1;
|
| 312 |
|
|
if (SHpnt->some_device_starved) {
|
| 313 |
|
|
for (SDpnt = SHpnt->host_queue; SDpnt; SDpnt = SDpnt->next) {
|
| 314 |
|
|
request_queue_t *q;
|
| 315 |
|
|
if ((SHpnt->can_queue > 0 && (SHpnt->host_busy >= SHpnt->can_queue))
|
| 316 |
|
|
|| (SHpnt->host_blocked)
|
| 317 |
|
|
|| (SHpnt->host_self_blocked)) {
|
| 318 |
|
|
break;
|
| 319 |
|
|
}
|
| 320 |
|
|
if (SDpnt->device_blocked || !SDpnt->starved) {
|
| 321 |
|
|
continue;
|
| 322 |
|
|
}
|
| 323 |
|
|
q = &SDpnt->request_queue;
|
| 324 |
|
|
q->request_fn(q);
|
| 325 |
|
|
all_clear = 0;
|
| 326 |
|
|
}
|
| 327 |
|
|
if (SDpnt == NULL && all_clear) {
|
| 328 |
|
|
SHpnt->some_device_starved = 0;
|
| 329 |
|
|
}
|
| 330 |
|
|
}
|
| 331 |
|
|
spin_unlock_irqrestore(&io_request_lock, flags);
|
| 332 |
|
|
}
|
| 333 |
|
|
|
| 334 |
|
|
/*
|
| 335 |
|
|
* Function: scsi_end_request()
|
| 336 |
|
|
*
|
| 337 |
|
|
* Purpose: Post-processing of completed commands called from interrupt
|
| 338 |
|
|
* handler or a bottom-half handler.
|
| 339 |
|
|
*
|
| 340 |
|
|
* Arguments: SCpnt - command that is complete.
|
| 341 |
|
|
* uptodate - 1 if I/O indicates success, 0 for I/O error.
|
| 342 |
|
|
* sectors - number of sectors we want to mark.
|
| 343 |
|
|
* requeue - indicates whether we should requeue leftovers.
|
| 344 |
|
|
* frequeue - indicates that if we release the command block
|
| 345 |
|
|
* that the queue request function should be called.
|
| 346 |
|
|
*
|
| 347 |
|
|
* Lock status: Assumed that lock is not held upon entry.
|
| 348 |
|
|
*
|
| 349 |
|
|
* Returns: Nothing
|
| 350 |
|
|
*
|
| 351 |
|
|
* Notes: This is called for block device requests in order to
|
| 352 |
|
|
* mark some number of sectors as complete.
|
| 353 |
|
|
*
|
| 354 |
|
|
* We are guaranteeing that the request queue will be goosed
|
| 355 |
|
|
* at some point during this call.
|
| 356 |
|
|
*/
|
| 357 |
|
|
static Scsi_Cmnd *__scsi_end_request(Scsi_Cmnd * SCpnt,
|
| 358 |
|
|
int uptodate,
|
| 359 |
|
|
int sectors,
|
| 360 |
|
|
int requeue,
|
| 361 |
|
|
int frequeue)
|
| 362 |
|
|
{
|
| 363 |
|
|
request_queue_t *q = &SCpnt->device->request_queue;
|
| 364 |
|
|
struct request *req;
|
| 365 |
|
|
struct buffer_head *bh;
|
| 366 |
|
|
unsigned long flags;
|
| 367 |
|
|
int nsect;
|
| 368 |
|
|
|
| 369 |
|
|
ASSERT_LOCK(&io_request_lock, 0);
|
| 370 |
|
|
|
| 371 |
|
|
req = &SCpnt->request;
|
| 372 |
|
|
req->errors = 0;
|
| 373 |
|
|
if (!uptodate) {
|
| 374 |
|
|
printk(" I/O error: dev %s, sector %lu\n",
|
| 375 |
|
|
kdevname(req->rq_dev), req->sector);
|
| 376 |
|
|
}
|
| 377 |
|
|
do {
|
| 378 |
|
|
if ((bh = req->bh) != NULL) {
|
| 379 |
|
|
nsect = bh->b_size >> 9;
|
| 380 |
|
|
blk_finished_io(nsect);
|
| 381 |
|
|
blk_finished_sectors(req, nsect);
|
| 382 |
|
|
req->bh = bh->b_reqnext;
|
| 383 |
|
|
bh->b_reqnext = NULL;
|
| 384 |
|
|
sectors -= nsect;
|
| 385 |
|
|
bh->b_end_io(bh, uptodate);
|
| 386 |
|
|
if ((bh = req->bh) != NULL) {
|
| 387 |
|
|
req->hard_sector += nsect;
|
| 388 |
|
|
req->hard_nr_sectors -= nsect;
|
| 389 |
|
|
req->sector += nsect;
|
| 390 |
|
|
req->nr_sectors -= nsect;
|
| 391 |
|
|
|
| 392 |
|
|
req->current_nr_sectors = bh->b_size >> 9;
|
| 393 |
|
|
req->hard_cur_sectors = req->current_nr_sectors;
|
| 394 |
|
|
if (req->nr_sectors < req->current_nr_sectors) {
|
| 395 |
|
|
req->nr_sectors = req->current_nr_sectors;
|
| 396 |
|
|
printk("scsi_end_request: buffer-list destroyed\n");
|
| 397 |
|
|
}
|
| 398 |
|
|
}
|
| 399 |
|
|
}
|
| 400 |
|
|
} while (sectors && bh);
|
| 401 |
|
|
|
| 402 |
|
|
/*
|
| 403 |
|
|
* If there are blocks left over at the end, set up the command
|
| 404 |
|
|
* to queue the remainder of them.
|
| 405 |
|
|
*/
|
| 406 |
|
|
if (req->bh) {
|
| 407 |
|
|
/*
|
| 408 |
|
|
* Recount segments whether we are immediately going to
|
| 409 |
|
|
* requeue the command or not, other code might requeue
|
| 410 |
|
|
* it later and since we changed the segment count up above,
|
| 411 |
|
|
* we need it updated.
|
| 412 |
|
|
*/
|
| 413 |
|
|
recount_segments(SCpnt);
|
| 414 |
|
|
|
| 415 |
|
|
/*
|
| 416 |
|
|
* Bleah. Leftovers again. Stick the leftovers in
|
| 417 |
|
|
* the front of the queue, and goose the queue again.
|
| 418 |
|
|
*/
|
| 419 |
|
|
if (requeue)
|
| 420 |
|
|
scsi_queue_next_request(q, SCpnt);
|
| 421 |
|
|
|
| 422 |
|
|
return SCpnt;
|
| 423 |
|
|
}
|
| 424 |
|
|
|
| 425 |
|
|
/*
|
| 426 |
|
|
* This request is done. If there is someone blocked waiting for this
|
| 427 |
|
|
* request, wake them up. Typically used to wake up processes trying
|
| 428 |
|
|
* to swap a page into memory.
|
| 429 |
|
|
*/
|
| 430 |
|
|
if (req->waiting)
|
| 431 |
|
|
complete(req->waiting);
|
| 432 |
|
|
|
| 433 |
|
|
spin_lock_irqsave(&io_request_lock, flags);
|
| 434 |
|
|
req_finished_io(req);
|
| 435 |
|
|
spin_unlock_irqrestore(&io_request_lock, flags);
|
| 436 |
|
|
|
| 437 |
|
|
add_blkdev_randomness(MAJOR(req->rq_dev));
|
| 438 |
|
|
|
| 439 |
|
|
/*
|
| 440 |
|
|
* This will goose the queue request function at the end, so we don't
|
| 441 |
|
|
* need to worry about launching another command.
|
| 442 |
|
|
*/
|
| 443 |
|
|
__scsi_release_command(SCpnt);
|
| 444 |
|
|
|
| 445 |
|
|
if (frequeue)
|
| 446 |
|
|
scsi_queue_next_request(q, NULL);
|
| 447 |
|
|
|
| 448 |
|
|
return NULL;
|
| 449 |
|
|
}
|
| 450 |
|
|
|
| 451 |
|
|
/*
|
| 452 |
|
|
* Function: scsi_end_request()
|
| 453 |
|
|
*
|
| 454 |
|
|
* Purpose: Post-processing of completed commands called from interrupt
|
| 455 |
|
|
* handler or a bottom-half handler.
|
| 456 |
|
|
*
|
| 457 |
|
|
* Arguments: SCpnt - command that is complete.
|
| 458 |
|
|
* uptodate - 1 if I/O indicates success, 0 for I/O error.
|
| 459 |
|
|
* sectors - number of sectors we want to mark.
|
| 460 |
|
|
*
|
| 461 |
|
|
* Lock status: Assumed that lock is not held upon entry.
|
| 462 |
|
|
*
|
| 463 |
|
|
* Returns: Nothing
|
| 464 |
|
|
*
|
| 465 |
|
|
* Notes: This is called for block device requests in order to
|
| 466 |
|
|
* mark some number of sectors as complete.
|
| 467 |
|
|
*
|
| 468 |
|
|
* We are guaranteeing that the request queue will be goosed
|
| 469 |
|
|
* at some point during this call.
|
| 470 |
|
|
*/
|
| 471 |
|
|
Scsi_Cmnd *scsi_end_request(Scsi_Cmnd * SCpnt, int uptodate, int sectors)
|
| 472 |
|
|
{
|
| 473 |
|
|
return __scsi_end_request(SCpnt, uptodate, sectors, 1, 1);
|
| 474 |
|
|
}
|
| 475 |
|
|
|
| 476 |
|
|
/*
|
| 477 |
|
|
* Function: scsi_release_buffers()
|
| 478 |
|
|
*
|
| 479 |
|
|
* Purpose: Completion processing for block device I/O requests.
|
| 480 |
|
|
*
|
| 481 |
|
|
* Arguments: SCpnt - command that we are bailing.
|
| 482 |
|
|
*
|
| 483 |
|
|
* Lock status: Assumed that no lock is held upon entry.
|
| 484 |
|
|
*
|
| 485 |
|
|
* Returns: Nothing
|
| 486 |
|
|
*
|
| 487 |
|
|
* Notes: In the event that an upper level driver rejects a
|
| 488 |
|
|
* command, we must release resources allocated during
|
| 489 |
|
|
* the __init_io() function. Primarily this would involve
|
| 490 |
|
|
* the scatter-gather table, and potentially any bounce
|
| 491 |
|
|
* buffers.
|
| 492 |
|
|
*/
|
| 493 |
|
|
static void scsi_release_buffers(Scsi_Cmnd * SCpnt)
|
| 494 |
|
|
{
|
| 495 |
|
|
ASSERT_LOCK(&io_request_lock, 0);
|
| 496 |
|
|
|
| 497 |
|
|
/*
|
| 498 |
|
|
* Free up any indirection buffers we allocated for DMA purposes.
|
| 499 |
|
|
*/
|
| 500 |
|
|
if (SCpnt->use_sg) {
|
| 501 |
|
|
struct scatterlist *sgpnt;
|
| 502 |
|
|
void **bbpnt;
|
| 503 |
|
|
int i;
|
| 504 |
|
|
|
| 505 |
|
|
sgpnt = (struct scatterlist *) SCpnt->request_buffer;
|
| 506 |
|
|
bbpnt = SCpnt->bounce_buffers;
|
| 507 |
|
|
|
| 508 |
|
|
if (bbpnt) {
|
| 509 |
|
|
for (i = 0; i < SCpnt->use_sg; i++) {
|
| 510 |
|
|
if (bbpnt[i])
|
| 511 |
|
|
scsi_free(sgpnt[i].address, sgpnt[i].length);
|
| 512 |
|
|
}
|
| 513 |
|
|
}
|
| 514 |
|
|
scsi_free(SCpnt->request_buffer, SCpnt->sglist_len);
|
| 515 |
|
|
} else {
|
| 516 |
|
|
if (SCpnt->request_buffer != SCpnt->request.buffer) {
|
| 517 |
|
|
scsi_free(SCpnt->request_buffer, SCpnt->request_bufflen);
|
| 518 |
|
|
}
|
| 519 |
|
|
}
|
| 520 |
|
|
|
| 521 |
|
|
/*
|
| 522 |
|
|
* Zero these out. They now point to freed memory, and it is
|
| 523 |
|
|
* dangerous to hang onto the pointers.
|
| 524 |
|
|
*/
|
| 525 |
|
|
SCpnt->buffer = NULL;
|
| 526 |
|
|
SCpnt->bufflen = 0;
|
| 527 |
|
|
SCpnt->request_buffer = NULL;
|
| 528 |
|
|
SCpnt->request_bufflen = 0;
|
| 529 |
|
|
}
|
| 530 |
|
|
|
| 531 |
|
|
/*
|
| 532 |
|
|
* Function: scsi_io_completion()
|
| 533 |
|
|
*
|
| 534 |
|
|
* Purpose: Completion processing for block device I/O requests.
|
| 535 |
|
|
*
|
| 536 |
|
|
* Arguments: SCpnt - command that is finished.
|
| 537 |
|
|
*
|
| 538 |
|
|
* Lock status: Assumed that no lock is held upon entry.
|
| 539 |
|
|
*
|
| 540 |
|
|
* Returns: Nothing
|
| 541 |
|
|
*
|
| 542 |
|
|
* Notes: This function is matched in terms of capabilities to
|
| 543 |
|
|
* the function that created the scatter-gather list.
|
| 544 |
|
|
* In other words, if there are no bounce buffers
|
| 545 |
|
|
* (the normal case for most drivers), we don't need
|
| 546 |
|
|
* the logic to deal with cleaning up afterwards.
|
| 547 |
|
|
*/
|
| 548 |
|
|
void scsi_io_completion(Scsi_Cmnd * SCpnt, int good_sectors,
|
| 549 |
|
|
int block_sectors)
|
| 550 |
|
|
{
|
| 551 |
|
|
int result = SCpnt->result;
|
| 552 |
|
|
int this_count = SCpnt->bufflen >> 9;
|
| 553 |
|
|
request_queue_t *q = &SCpnt->device->request_queue;
|
| 554 |
|
|
struct request *req = &SCpnt->request;
|
| 555 |
|
|
|
| 556 |
|
|
/*
|
| 557 |
|
|
* We must do one of several things here:
|
| 558 |
|
|
*
|
| 559 |
|
|
* Call scsi_end_request. This will finish off the specified
|
| 560 |
|
|
* number of sectors. If we are done, the command block will
|
| 561 |
|
|
* be released, and the queue function will be goosed. If we
|
| 562 |
|
|
* are not done, then scsi_end_request will directly goose
|
| 563 |
|
|
* the queue.
|
| 564 |
|
|
*
|
| 565 |
|
|
* We can just use scsi_queue_next_request() here. This
|
| 566 |
|
|
* would be used if we just wanted to retry, for example.
|
| 567 |
|
|
*
|
| 568 |
|
|
*/
|
| 569 |
|
|
ASSERT_LOCK(&io_request_lock, 0);
|
| 570 |
|
|
|
| 571 |
|
|
/*
|
| 572 |
|
|
* Free up any indirection buffers we allocated for DMA purposes.
|
| 573 |
|
|
* For the case of a READ, we need to copy the data out of the
|
| 574 |
|
|
* bounce buffer and into the real buffer.
|
| 575 |
|
|
*/
|
| 576 |
|
|
if (SCpnt->use_sg) {
|
| 577 |
|
|
struct scatterlist *sgpnt;
|
| 578 |
|
|
void **bbpnt;
|
| 579 |
|
|
int i;
|
| 580 |
|
|
|
| 581 |
|
|
sgpnt = (struct scatterlist *) SCpnt->buffer;
|
| 582 |
|
|
bbpnt = SCpnt->bounce_buffers;
|
| 583 |
|
|
|
| 584 |
|
|
if (bbpnt) {
|
| 585 |
|
|
for (i = 0; i < SCpnt->use_sg; i++) {
|
| 586 |
|
|
if (bbpnt[i]) {
|
| 587 |
|
|
if (req->cmd == READ) {
|
| 588 |
|
|
memcpy(bbpnt[i],
|
| 589 |
|
|
sgpnt[i].address,
|
| 590 |
|
|
sgpnt[i].length);
|
| 591 |
|
|
}
|
| 592 |
|
|
scsi_free(sgpnt[i].address, sgpnt[i].length);
|
| 593 |
|
|
}
|
| 594 |
|
|
}
|
| 595 |
|
|
}
|
| 596 |
|
|
scsi_free(SCpnt->buffer, SCpnt->sglist_len);
|
| 597 |
|
|
} else {
|
| 598 |
|
|
if (SCpnt->buffer != req->buffer) {
|
| 599 |
|
|
if (PageHighMem(req->bh->b_page))
|
| 600 |
|
|
BUG();
|
| 601 |
|
|
if (req->cmd == READ)
|
| 602 |
|
|
memcpy(req->buffer, SCpnt->buffer, SCpnt->bufflen);
|
| 603 |
|
|
scsi_free(SCpnt->buffer, SCpnt->bufflen);
|
| 604 |
|
|
}
|
| 605 |
|
|
}
|
| 606 |
|
|
|
| 607 |
|
|
/*
|
| 608 |
|
|
* Zero these out. They now point to freed memory, and it is
|
| 609 |
|
|
* dangerous to hang onto the pointers.
|
| 610 |
|
|
*/
|
| 611 |
|
|
SCpnt->buffer = NULL;
|
| 612 |
|
|
SCpnt->bufflen = 0;
|
| 613 |
|
|
SCpnt->request_buffer = NULL;
|
| 614 |
|
|
SCpnt->request_bufflen = 0;
|
| 615 |
|
|
|
| 616 |
|
|
/*
|
| 617 |
|
|
* Next deal with any sectors which we were able to correctly
|
| 618 |
|
|
* handle.
|
| 619 |
|
|
*/
|
| 620 |
|
|
if (good_sectors > 0) {
|
| 621 |
|
|
SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, %d sectors done.\n",
|
| 622 |
|
|
SCpnt->request.nr_sectors,
|
| 623 |
|
|
good_sectors));
|
| 624 |
|
|
SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n ", SCpnt->use_sg));
|
| 625 |
|
|
|
| 626 |
|
|
req->errors = 0;
|
| 627 |
|
|
/*
|
| 628 |
|
|
* If multiple sectors are requested in one buffer, then
|
| 629 |
|
|
* they will have been finished off by the first command.
|
| 630 |
|
|
* If not, then we have a multi-buffer command.
|
| 631 |
|
|
*
|
| 632 |
|
|
* If block_sectors != 0, it means we had a medium error
|
| 633 |
|
|
* of some sort, and that we want to mark some number of
|
| 634 |
|
|
* sectors as not uptodate. Thus we want to inhibit
|
| 635 |
|
|
* requeueing right here - we will requeue down below
|
| 636 |
|
|
* when we handle the bad sectors.
|
| 637 |
|
|
*/
|
| 638 |
|
|
SCpnt = __scsi_end_request(SCpnt,
|
| 639 |
|
|
1,
|
| 640 |
|
|
good_sectors,
|
| 641 |
|
|
result == 0,
|
| 642 |
|
|
1);
|
| 643 |
|
|
|
| 644 |
|
|
/*
|
| 645 |
|
|
* If the command completed without error, then either finish off the
|
| 646 |
|
|
* rest of the command, or start a new one.
|
| 647 |
|
|
*/
|
| 648 |
|
|
if (result == 0 || SCpnt == NULL ) {
|
| 649 |
|
|
return;
|
| 650 |
|
|
}
|
| 651 |
|
|
}
|
| 652 |
|
|
/*
|
| 653 |
|
|
* Now, if we were good little boys and girls, Santa left us a request
|
| 654 |
|
|
* sense buffer. We can extract information from this, so we
|
| 655 |
|
|
* can choose a block to remap, etc.
|
| 656 |
|
|
*/
|
| 657 |
|
|
if (driver_byte(result) != 0) {
|
| 658 |
|
|
if (suggestion(result) == SUGGEST_REMAP) {
|
| 659 |
|
|
#ifdef REMAP
|
| 660 |
|
|
/*
|
| 661 |
|
|
* Not yet implemented. A read will fail after being remapped,
|
| 662 |
|
|
* a write will call the strategy routine again.
|
| 663 |
|
|
*/
|
| 664 |
|
|
if (SCpnt->device->remap) {
|
| 665 |
|
|
result = 0;
|
| 666 |
|
|
}
|
| 667 |
|
|
#endif
|
| 668 |
|
|
}
|
| 669 |
|
|
if ((SCpnt->sense_buffer[0] & 0x7f) == 0x70) {
|
| 670 |
|
|
/*
|
| 671 |
|
|
* If the device is in the process of becoming ready,
|
| 672 |
|
|
* retry.
|
| 673 |
|
|
*/
|
| 674 |
|
|
if (SCpnt->sense_buffer[12] == 0x04 &&
|
| 675 |
|
|
SCpnt->sense_buffer[13] == 0x01) {
|
| 676 |
|
|
scsi_queue_next_request(q, SCpnt);
|
| 677 |
|
|
return;
|
| 678 |
|
|
}
|
| 679 |
|
|
if ((SCpnt->sense_buffer[2] & 0xf) == UNIT_ATTENTION) {
|
| 680 |
|
|
if (SCpnt->device->removable) {
|
| 681 |
|
|
/* detected disc change. set a bit
|
| 682 |
|
|
* and quietly refuse further access.
|
| 683 |
|
|
*/
|
| 684 |
|
|
SCpnt->device->changed = 1;
|
| 685 |
|
|
SCpnt = scsi_end_request(SCpnt, 0, this_count);
|
| 686 |
|
|
return;
|
| 687 |
|
|
} else {
|
| 688 |
|
|
/*
|
| 689 |
|
|
* Must have been a power glitch, or a
|
| 690 |
|
|
* bus reset. Could not have been a
|
| 691 |
|
|
* media change, so we just retry the
|
| 692 |
|
|
* request and see what happens.
|
| 693 |
|
|
*/
|
| 694 |
|
|
scsi_queue_next_request(q, SCpnt);
|
| 695 |
|
|
return;
|
| 696 |
|
|
}
|
| 697 |
|
|
}
|
| 698 |
|
|
}
|
| 699 |
|
|
/* If we had an ILLEGAL REQUEST returned, then we may have
|
| 700 |
|
|
* performed an unsupported command. The only thing this should be
|
| 701 |
|
|
* would be a ten byte read where only a six byte read was supported.
|
| 702 |
|
|
* Also, on a system where READ CAPACITY failed, we have have read
|
| 703 |
|
|
* past the end of the disk.
|
| 704 |
|
|
*/
|
| 705 |
|
|
|
| 706 |
|
|
switch (SCpnt->sense_buffer[2]) {
|
| 707 |
|
|
case RECOVERED_ERROR: /* Added, KG, 2003-01-20 */
|
| 708 |
|
|
return;
|
| 709 |
|
|
case ILLEGAL_REQUEST:
|
| 710 |
|
|
if (SCpnt->device->ten && SCSI_RETRY_10(SCpnt->cmnd[0])) {
|
| 711 |
|
|
SCpnt->device->ten = 0;
|
| 712 |
|
|
/*
|
| 713 |
|
|
* This will cause a retry with a 6-byte
|
| 714 |
|
|
* command.
|
| 715 |
|
|
*/
|
| 716 |
|
|
scsi_queue_next_request(q, SCpnt);
|
| 717 |
|
|
result = 0;
|
| 718 |
|
|
} else {
|
| 719 |
|
|
SCpnt = scsi_end_request(SCpnt, 0, this_count);
|
| 720 |
|
|
return;
|
| 721 |
|
|
}
|
| 722 |
|
|
break;
|
| 723 |
|
|
case NOT_READY:
|
| 724 |
|
|
printk(KERN_INFO "Device %s not ready.\n",
|
| 725 |
|
|
kdevname(SCpnt->request.rq_dev));
|
| 726 |
|
|
SCpnt = scsi_end_request(SCpnt, 0, this_count);
|
| 727 |
|
|
return;
|
| 728 |
|
|
break;
|
| 729 |
|
|
case MEDIUM_ERROR:
|
| 730 |
|
|
case VOLUME_OVERFLOW:
|
| 731 |
|
|
printk("scsi%d: ERROR on channel %d, id %d, lun %d, CDB: ",
|
| 732 |
|
|
SCpnt->host->host_no, (int) SCpnt->channel,
|
| 733 |
|
|
(int) SCpnt->target, (int) SCpnt->lun);
|
| 734 |
|
|
print_command(SCpnt->cmnd);
|
| 735 |
|
|
print_sense("sd", SCpnt);
|
| 736 |
|
|
SCpnt = scsi_end_request(SCpnt, 0, block_sectors);
|
| 737 |
|
|
return;
|
| 738 |
|
|
default:
|
| 739 |
|
|
break;
|
| 740 |
|
|
}
|
| 741 |
|
|
} /* driver byte != 0 */
|
| 742 |
|
|
if (host_byte(result) == DID_RESET) {
|
| 743 |
|
|
/*
|
| 744 |
|
|
* Third party bus reset or reset for error
|
| 745 |
|
|
* recovery reasons. Just retry the request
|
| 746 |
|
|
* and see what happens.
|
| 747 |
|
|
*/
|
| 748 |
|
|
scsi_queue_next_request(q, SCpnt);
|
| 749 |
|
|
return;
|
| 750 |
|
|
}
|
| 751 |
|
|
if (result) {
|
| 752 |
|
|
struct Scsi_Device_Template *STpnt;
|
| 753 |
|
|
|
| 754 |
|
|
STpnt = scsi_get_request_dev(&SCpnt->request);
|
| 755 |
|
|
printk("SCSI %s error : host %d channel %d id %d lun %d return code = %x\n",
|
| 756 |
|
|
(STpnt ? STpnt->name : "device"),
|
| 757 |
|
|
SCpnt->device->host->host_no,
|
| 758 |
|
|
SCpnt->device->channel,
|
| 759 |
|
|
SCpnt->device->id,
|
| 760 |
|
|
SCpnt->device->lun, result);
|
| 761 |
|
|
|
| 762 |
|
|
if (driver_byte(result) & DRIVER_SENSE)
|
| 763 |
|
|
print_sense("sd", SCpnt);
|
| 764 |
|
|
/*
|
| 765 |
|
|
* Mark a single buffer as not uptodate. Queue the remainder.
|
| 766 |
|
|
* We sometimes get this cruft in the event that a medium error
|
| 767 |
|
|
* isn't properly reported.
|
| 768 |
|
|
*/
|
| 769 |
|
|
SCpnt = scsi_end_request(SCpnt, 0, SCpnt->request.current_nr_sectors);
|
| 770 |
|
|
return;
|
| 771 |
|
|
}
|
| 772 |
|
|
}
|
| 773 |
|
|
|
| 774 |
|
|
/*
|
| 775 |
|
|
* Function: scsi_get_request_dev()
|
| 776 |
|
|
*
|
| 777 |
|
|
* Purpose: Find the upper-level driver that is responsible for this
|
| 778 |
|
|
* request
|
| 779 |
|
|
*
|
| 780 |
|
|
* Arguments: request - I/O request we are preparing to queue.
|
| 781 |
|
|
*
|
| 782 |
|
|
* Lock status: No locks assumed to be held, but as it happens the
|
| 783 |
|
|
* io_request_lock is held when this is called.
|
| 784 |
|
|
*
|
| 785 |
|
|
* Returns: Nothing
|
| 786 |
|
|
*
|
| 787 |
|
|
* Notes: The requests in the request queue may have originated
|
| 788 |
|
|
* from any block device driver. We need to find out which
|
| 789 |
|
|
* one so that we can later form the appropriate command.
|
| 790 |
|
|
*/
|
| 791 |
|
|
struct Scsi_Device_Template *scsi_get_request_dev(struct request *req)
|
| 792 |
|
|
{
|
| 793 |
|
|
struct Scsi_Device_Template *spnt;
|
| 794 |
|
|
kdev_t dev = req->rq_dev;
|
| 795 |
|
|
int major = MAJOR(dev);
|
| 796 |
|
|
|
| 797 |
|
|
ASSERT_LOCK(&io_request_lock, 1);
|
| 798 |
|
|
|
| 799 |
|
|
for (spnt = scsi_devicelist; spnt; spnt = spnt->next) {
|
| 800 |
|
|
/*
|
| 801 |
|
|
* Search for a block device driver that supports this
|
| 802 |
|
|
* major.
|
| 803 |
|
|
*/
|
| 804 |
|
|
if (spnt->blk && spnt->major == major) {
|
| 805 |
|
|
return spnt;
|
| 806 |
|
|
}
|
| 807 |
|
|
/*
|
| 808 |
|
|
* I am still not entirely satisfied with this solution,
|
| 809 |
|
|
* but it is good enough for now. Disks have a number of
|
| 810 |
|
|
* major numbers associated with them, the primary
|
| 811 |
|
|
* 8, which we test above, and a secondary range of 7
|
| 812 |
|
|
* different consecutive major numbers. If this ever
|
| 813 |
|
|
* becomes insufficient, then we could add another function
|
| 814 |
|
|
* to the structure, and generalize this completely.
|
| 815 |
|
|
*/
|
| 816 |
|
|
if( spnt->min_major != 0
|
| 817 |
|
|
&& spnt->max_major != 0
|
| 818 |
|
|
&& major >= spnt->min_major
|
| 819 |
|
|
&& major <= spnt->max_major )
|
| 820 |
|
|
{
|
| 821 |
|
|
return spnt;
|
| 822 |
|
|
}
|
| 823 |
|
|
}
|
| 824 |
|
|
return NULL;
|
| 825 |
|
|
}
|
| 826 |
|
|
|
| 827 |
|
|
/*
|
| 828 |
|
|
* Function: scsi_request_fn()
|
| 829 |
|
|
*
|
| 830 |
|
|
* Purpose: Generic version of request function for SCSI hosts.
|
| 831 |
|
|
*
|
| 832 |
|
|
* Arguments: q - Pointer to actual queue.
|
| 833 |
|
|
*
|
| 834 |
|
|
* Returns: Nothing
|
| 835 |
|
|
*
|
| 836 |
|
|
* Lock status: IO request lock assumed to be held when called.
|
| 837 |
|
|
*
|
| 838 |
|
|
* Notes: The theory is that this function is something which individual
|
| 839 |
|
|
* drivers could also supply if they wished to. The problem
|
| 840 |
|
|
* is that we have 30 some odd low-level drivers in the kernel
|
| 841 |
|
|
* tree already, and it would be most difficult to retrofit
|
| 842 |
|
|
* this crap into all of them. Thus this function has the job
|
| 843 |
|
|
* of acting as a generic queue manager for all of those existing
|
| 844 |
|
|
* drivers.
|
| 845 |
|
|
*/
|
| 846 |
|
|
void scsi_request_fn(request_queue_t * q)
|
| 847 |
|
|
{
|
| 848 |
|
|
struct request *req;
|
| 849 |
|
|
Scsi_Cmnd *SCpnt;
|
| 850 |
|
|
Scsi_Request *SRpnt;
|
| 851 |
|
|
Scsi_Device *SDpnt;
|
| 852 |
|
|
struct Scsi_Host *SHpnt;
|
| 853 |
|
|
struct Scsi_Device_Template *STpnt;
|
| 854 |
|
|
|
| 855 |
|
|
ASSERT_LOCK(&io_request_lock, 1);
|
| 856 |
|
|
|
| 857 |
|
|
SDpnt = (Scsi_Device *) q->queuedata;
|
| 858 |
|
|
if (!SDpnt) {
|
| 859 |
|
|
panic("Missing device");
|
| 860 |
|
|
}
|
| 861 |
|
|
SHpnt = SDpnt->host;
|
| 862 |
|
|
|
| 863 |
|
|
/*
|
| 864 |
|
|
* To start with, we keep looping until the queue is empty, or until
|
| 865 |
|
|
* the host is no longer able to accept any more requests.
|
| 866 |
|
|
*/
|
| 867 |
|
|
while (1 == 1) {
|
| 868 |
|
|
/*
|
| 869 |
|
|
* Check this again - each time we loop through we will have
|
| 870 |
|
|
* released the lock and grabbed it again, so each time
|
| 871 |
|
|
* we need to check to see if the queue is plugged or not.
|
| 872 |
|
|
*/
|
| 873 |
|
|
if (SHpnt->in_recovery || q->plugged)
|
| 874 |
|
|
return;
|
| 875 |
|
|
|
| 876 |
|
|
/*
|
| 877 |
|
|
* If the device cannot accept another request, then quit.
|
| 878 |
|
|
*/
|
| 879 |
|
|
if (SDpnt->device_blocked) {
|
| 880 |
|
|
break;
|
| 881 |
|
|
}
|
| 882 |
|
|
if ((SHpnt->can_queue > 0 && (SHpnt->host_busy >= SHpnt->can_queue))
|
| 883 |
|
|
|| (SHpnt->host_blocked)
|
| 884 |
|
|
|| (SHpnt->host_self_blocked)) {
|
| 885 |
|
|
/*
|
| 886 |
|
|
* If we are unable to process any commands at all for
|
| 887 |
|
|
* this device, then we consider it to be starved.
|
| 888 |
|
|
* What this means is that there are no outstanding
|
| 889 |
|
|
* commands for this device and hence we need a
|
| 890 |
|
|
* little help getting it started again
|
| 891 |
|
|
* once the host isn't quite so busy.
|
| 892 |
|
|
*/
|
| 893 |
|
|
if (SDpnt->device_busy == 0) {
|
| 894 |
|
|
SDpnt->starved = 1;
|
| 895 |
|
|
SHpnt->some_device_starved = 1;
|
| 896 |
|
|
}
|
| 897 |
|
|
break;
|
| 898 |
|
|
} else {
|
| 899 |
|
|
SDpnt->starved = 0;
|
| 900 |
|
|
}
|
| 901 |
|
|
|
| 902 |
|
|
/*
|
| 903 |
|
|
* FIXME(eric)
|
| 904 |
|
|
* I am not sure where the best place to do this is. We need
|
| 905 |
|
|
* to hook in a place where we are likely to come if in user
|
| 906 |
|
|
* space. Technically the error handling thread should be
|
| 907 |
|
|
* doing this crap, but the error handler isn't used by
|
| 908 |
|
|
* most hosts.
|
| 909 |
|
|
*/
|
| 910 |
|
|
if (SDpnt->was_reset) {
|
| 911 |
|
|
/*
|
| 912 |
|
|
* We need to relock the door, but we might
|
| 913 |
|
|
* be in an interrupt handler. Only do this
|
| 914 |
|
|
* from user space, since we do not want to
|
| 915 |
|
|
* sleep from an interrupt.
|
| 916 |
|
|
*
|
| 917 |
|
|
* FIXME(eric) - have the error handler thread do
|
| 918 |
|
|
* this work.
|
| 919 |
|
|
*/
|
| 920 |
|
|
SDpnt->was_reset = 0;
|
| 921 |
|
|
if (SDpnt->removable && !in_interrupt()) {
|
| 922 |
|
|
spin_unlock_irq(&io_request_lock);
|
| 923 |
|
|
scsi_ioctl(SDpnt, SCSI_IOCTL_DOORLOCK, 0);
|
| 924 |
|
|
spin_lock_irq(&io_request_lock);
|
| 925 |
|
|
continue;
|
| 926 |
|
|
}
|
| 927 |
|
|
}
|
| 928 |
|
|
|
| 929 |
|
|
/*
|
| 930 |
|
|
* If we couldn't find a request that could be queued, then we
|
| 931 |
|
|
* can also quit.
|
| 932 |
|
|
*/
|
| 933 |
|
|
if (list_empty(&q->queue_head))
|
| 934 |
|
|
break;
|
| 935 |
|
|
|
| 936 |
|
|
/*
|
| 937 |
|
|
* Loop through all of the requests in this queue, and find
|
| 938 |
|
|
* one that is queueable.
|
| 939 |
|
|
*/
|
| 940 |
|
|
req = blkdev_entry_next_request(&q->queue_head);
|
| 941 |
|
|
|
| 942 |
|
|
/*
|
| 943 |
|
|
* Find the actual device driver associated with this command.
|
| 944 |
|
|
* The SPECIAL requests are things like character device or
|
| 945 |
|
|
* ioctls, which did not originate from ll_rw_blk. Note that
|
| 946 |
|
|
* the special field is also used to indicate the SCpnt for
|
| 947 |
|
|
* the remainder of a partially fulfilled request that can
|
| 948 |
|
|
* come up when there is a medium error. We have to treat
|
| 949 |
|
|
* these two cases differently. We differentiate by looking
|
| 950 |
|
|
* at request.cmd, as this tells us the real story.
|
| 951 |
|
|
*/
|
| 952 |
|
|
if (req->cmd == SPECIAL) {
|
| 953 |
|
|
STpnt = NULL;
|
| 954 |
|
|
SCpnt = (Scsi_Cmnd *) req->special;
|
| 955 |
|
|
SRpnt = (Scsi_Request *) req->special;
|
| 956 |
|
|
|
| 957 |
|
|
if( SRpnt->sr_magic == SCSI_REQ_MAGIC ) {
|
| 958 |
|
|
SCpnt = scsi_allocate_device(SRpnt->sr_device,
|
| 959 |
|
|
FALSE, FALSE);
|
| 960 |
|
|
if( !SCpnt ) {
|
| 961 |
|
|
break;
|
| 962 |
|
|
}
|
| 963 |
|
|
scsi_init_cmd_from_req(SCpnt, SRpnt);
|
| 964 |
|
|
}
|
| 965 |
|
|
|
| 966 |
|
|
} else {
|
| 967 |
|
|
SRpnt = NULL;
|
| 968 |
|
|
STpnt = scsi_get_request_dev(req);
|
| 969 |
|
|
if (!STpnt) {
|
| 970 |
|
|
panic("Unable to find device associated with request");
|
| 971 |
|
|
}
|
| 972 |
|
|
/*
|
| 973 |
|
|
* Now try and find a command block that we can use.
|
| 974 |
|
|
*/
|
| 975 |
|
|
if( req->special != NULL ) {
|
| 976 |
|
|
SCpnt = (Scsi_Cmnd *) req->special;
|
| 977 |
|
|
} else {
|
| 978 |
|
|
SCpnt = scsi_allocate_device(SDpnt, FALSE, FALSE);
|
| 979 |
|
|
}
|
| 980 |
|
|
/*
|
| 981 |
|
|
* If so, we are ready to do something. Bump the count
|
| 982 |
|
|
* while the queue is locked and then break out of the
|
| 983 |
|
|
* loop. Otherwise loop around and try another request.
|
| 984 |
|
|
*/
|
| 985 |
|
|
if (!SCpnt) {
|
| 986 |
|
|
break;
|
| 987 |
|
|
}
|
| 988 |
|
|
}
|
| 989 |
|
|
|
| 990 |
|
|
/*
|
| 991 |
|
|
* Now bump the usage count for both the host and the
|
| 992 |
|
|
* device.
|
| 993 |
|
|
*/
|
| 994 |
|
|
SHpnt->host_busy++;
|
| 995 |
|
|
SDpnt->device_busy++;
|
| 996 |
|
|
|
| 997 |
|
|
/*
|
| 998 |
|
|
* Finally, before we release the lock, we copy the
|
| 999 |
|
|
* request to the command block, and remove the
|
| 1000 |
|
|
* request from the request list. Note that we always
|
| 1001 |
|
|
* operate on the queue head - there is absolutely no
|
| 1002 |
|
|
* reason to search the list, because all of the commands
|
| 1003 |
|
|
* in this queue are for the same device.
|
| 1004 |
|
|
*/
|
| 1005 |
|
|
blkdev_dequeue_request(req);
|
| 1006 |
|
|
|
| 1007 |
|
|
if (req != &SCpnt->request && req != &SRpnt->sr_request ) {
|
| 1008 |
|
|
memcpy(&SCpnt->request, req, sizeof(struct request));
|
| 1009 |
|
|
|
| 1010 |
|
|
/*
|
| 1011 |
|
|
* We have copied the data out of the request block -
|
| 1012 |
|
|
* it is now in a field in SCpnt. Release the request
|
| 1013 |
|
|
* block.
|
| 1014 |
|
|
*/
|
| 1015 |
|
|
blkdev_release_request(req);
|
| 1016 |
|
|
}
|
| 1017 |
|
|
/*
|
| 1018 |
|
|
* Now it is finally safe to release the lock. We are
|
| 1019 |
|
|
* not going to noodle the request list until this
|
| 1020 |
|
|
* request has been queued and we loop back to queue
|
| 1021 |
|
|
* another.
|
| 1022 |
|
|
*/
|
| 1023 |
|
|
req = NULL;
|
| 1024 |
|
|
spin_unlock_irq(&io_request_lock);
|
| 1025 |
|
|
|
| 1026 |
|
|
if (SCpnt->request.cmd != SPECIAL) {
|
| 1027 |
|
|
/*
|
| 1028 |
|
|
* This will do a couple of things:
|
| 1029 |
|
|
* 1) Fill in the actual SCSI command.
|
| 1030 |
|
|
* 2) Fill in any other upper-level specific fields
|
| 1031 |
|
|
* (timeout).
|
| 1032 |
|
|
*
|
| 1033 |
|
|
* If this returns 0, it means that the request failed
|
| 1034 |
|
|
* (reading past end of disk, reading offline device,
|
| 1035 |
|
|
* etc). This won't actually talk to the device, but
|
| 1036 |
|
|
* some kinds of consistency checking may cause the
|
| 1037 |
|
|
* request to be rejected immediately.
|
| 1038 |
|
|
*/
|
| 1039 |
|
|
if (STpnt == NULL) {
|
| 1040 |
|
|
STpnt = scsi_get_request_dev(req);
|
| 1041 |
|
|
}
|
| 1042 |
|
|
/*
|
| 1043 |
|
|
* This sets up the scatter-gather table (allocating if
|
| 1044 |
|
|
* required). Hosts that need bounce buffers will also
|
| 1045 |
|
|
* get those allocated here.
|
| 1046 |
|
|
*/
|
| 1047 |
|
|
if (!SDpnt->scsi_init_io_fn(SCpnt)) {
|
| 1048 |
|
|
/*
|
| 1049 |
|
|
* probably we ran out of sgtable memory, or
|
| 1050 |
|
|
* __init_io() wanted to revert to a single
|
| 1051 |
|
|
* segment request. this would require bouncing
|
| 1052 |
|
|
* on highmem i/o, so mark the device as
|
| 1053 |
|
|
* starved and continue later instead
|
| 1054 |
|
|
*/
|
| 1055 |
|
|
spin_lock_irq(&io_request_lock);
|
| 1056 |
|
|
SHpnt->host_busy--;
|
| 1057 |
|
|
SDpnt->device_busy--;
|
| 1058 |
|
|
if (SDpnt->device_busy == 0) {
|
| 1059 |
|
|
SDpnt->starved = 1;
|
| 1060 |
|
|
SHpnt->some_device_starved = 1;
|
| 1061 |
|
|
}
|
| 1062 |
|
|
SCpnt->request.special = SCpnt;
|
| 1063 |
|
|
list_add(&SCpnt->request.queue, &q->queue_head);
|
| 1064 |
|
|
break;
|
| 1065 |
|
|
}
|
| 1066 |
|
|
|
| 1067 |
|
|
/*
|
| 1068 |
|
|
* Initialize the actual SCSI command for this request.
|
| 1069 |
|
|
*/
|
| 1070 |
|
|
if (!STpnt->init_command(SCpnt)) {
|
| 1071 |
|
|
scsi_release_buffers(SCpnt);
|
| 1072 |
|
|
SCpnt = __scsi_end_request(SCpnt, 0,
|
| 1073 |
|
|
SCpnt->request.nr_sectors, 0, 0);
|
| 1074 |
|
|
if( SCpnt != NULL )
|
| 1075 |
|
|
{
|
| 1076 |
|
|
panic("Should not have leftover blocks\n");
|
| 1077 |
|
|
}
|
| 1078 |
|
|
spin_lock_irq(&io_request_lock);
|
| 1079 |
|
|
SHpnt->host_busy--;
|
| 1080 |
|
|
SDpnt->device_busy--;
|
| 1081 |
|
|
continue;
|
| 1082 |
|
|
}
|
| 1083 |
|
|
}
|
| 1084 |
|
|
/*
|
| 1085 |
|
|
* Finally, initialize any error handling parameters, and set up
|
| 1086 |
|
|
* the timers for timeouts.
|
| 1087 |
|
|
*/
|
| 1088 |
|
|
scsi_init_cmd_errh(SCpnt);
|
| 1089 |
|
|
|
| 1090 |
|
|
/*
|
| 1091 |
|
|
* Dispatch the command to the low-level driver.
|
| 1092 |
|
|
*/
|
| 1093 |
|
|
scsi_dispatch_cmd(SCpnt);
|
| 1094 |
|
|
|
| 1095 |
|
|
/*
|
| 1096 |
|
|
* Now we need to grab the lock again. We are about to mess
|
| 1097 |
|
|
* with the request queue and try to find another command.
|
| 1098 |
|
|
*/
|
| 1099 |
|
|
spin_lock_irq(&io_request_lock);
|
| 1100 |
|
|
}
|
| 1101 |
|
|
}
|
| 1102 |
|
|
|
| 1103 |
|
|
/*
|
| 1104 |
|
|
* Function: scsi_block_requests()
|
| 1105 |
|
|
*
|
| 1106 |
|
|
* Purpose: Utility function used by low-level drivers to prevent further
|
| 1107 |
|
|
* commands from being queued to the device.
|
| 1108 |
|
|
*
|
| 1109 |
|
|
* Arguments: SHpnt - Host in question
|
| 1110 |
|
|
*
|
| 1111 |
|
|
* Returns: Nothing
|
| 1112 |
|
|
*
|
| 1113 |
|
|
* Lock status: No locks are assumed held.
|
| 1114 |
|
|
*
|
| 1115 |
|
|
* Notes: There is no timer nor any other means by which the requests
|
| 1116 |
|
|
* get unblocked other than the low-level driver calling
|
| 1117 |
|
|
* scsi_unblock_requests().
|
| 1118 |
|
|
*/
|
| 1119 |
|
|
void scsi_block_requests(struct Scsi_Host * SHpnt)
|
| 1120 |
|
|
{
|
| 1121 |
|
|
SHpnt->host_self_blocked = TRUE;
|
| 1122 |
|
|
}
|
| 1123 |
|
|
|
| 1124 |
|
|
/*
|
| 1125 |
|
|
* Function: scsi_unblock_requests()
|
| 1126 |
|
|
*
|
| 1127 |
|
|
* Purpose: Utility function used by low-level drivers to allow further
|
| 1128 |
|
|
* commands from being queued to the device.
|
| 1129 |
|
|
*
|
| 1130 |
|
|
* Arguments: SHpnt - Host in question
|
| 1131 |
|
|
*
|
| 1132 |
|
|
* Returns: Nothing
|
| 1133 |
|
|
*
|
| 1134 |
|
|
* Lock status: No locks are assumed held.
|
| 1135 |
|
|
*
|
| 1136 |
|
|
* Notes: There is no timer nor any other means by which the requests
|
| 1137 |
|
|
* get unblocked other than the low-level driver calling
|
| 1138 |
|
|
* scsi_unblock_requests().
|
| 1139 |
|
|
*
|
| 1140 |
|
|
* This is done as an API function so that changes to the
|
| 1141 |
|
|
* internals of the scsi mid-layer won't require wholesale
|
| 1142 |
|
|
* changes to drivers that use this feature.
|
| 1143 |
|
|
*/
|
| 1144 |
|
|
void scsi_unblock_requests(struct Scsi_Host * SHpnt)
|
| 1145 |
|
|
{
|
| 1146 |
|
|
Scsi_Device *SDloop;
|
| 1147 |
|
|
|
| 1148 |
|
|
SHpnt->host_self_blocked = FALSE;
|
| 1149 |
|
|
/* Now that we are unblocked, try to start the queues. */
|
| 1150 |
|
|
for (SDloop = SHpnt->host_queue; SDloop; SDloop = SDloop->next)
|
| 1151 |
|
|
scsi_queue_next_request(&SDloop->request_queue, NULL);
|
| 1152 |
|
|
}
|
| 1153 |
|
|
|
| 1154 |
|
|
/*
|
| 1155 |
|
|
* Function: scsi_report_bus_reset()
|
| 1156 |
|
|
*
|
| 1157 |
|
|
* Purpose: Utility function used by low-level drivers to report that
|
| 1158 |
|
|
* they have observed a bus reset on the bus being handled.
|
| 1159 |
|
|
*
|
| 1160 |
|
|
* Arguments: SHpnt - Host in question
|
| 1161 |
|
|
* channel - channel on which reset was observed.
|
| 1162 |
|
|
*
|
| 1163 |
|
|
* Returns: Nothing
|
| 1164 |
|
|
*
|
| 1165 |
|
|
* Lock status: No locks are assumed held.
|
| 1166 |
|
|
*
|
| 1167 |
|
|
* Notes: This only needs to be called if the reset is one which
|
| 1168 |
|
|
* originates from an unknown location. Resets originated
|
| 1169 |
|
|
* by the mid-level itself don't need to call this, but there
|
| 1170 |
|
|
* should be no harm.
|
| 1171 |
|
|
*
|
| 1172 |
|
|
* The main purpose of this is to make sure that a CHECK_CONDITION
|
| 1173 |
|
|
* is properly treated.
|
| 1174 |
|
|
*/
|
| 1175 |
|
|
void scsi_report_bus_reset(struct Scsi_Host * SHpnt, int channel)
|
| 1176 |
|
|
{
|
| 1177 |
|
|
Scsi_Device *SDloop;
|
| 1178 |
|
|
for (SDloop = SHpnt->host_queue; SDloop; SDloop = SDloop->next) {
|
| 1179 |
|
|
if (channel == SDloop->channel) {
|
| 1180 |
|
|
SDloop->was_reset = 1;
|
| 1181 |
|
|
SDloop->expecting_cc_ua = 1;
|
| 1182 |
|
|
}
|
| 1183 |
|
|
}
|
| 1184 |
|
|
}
|
| 1185 |
|
|
|
| 1186 |
|
|
/*
|
| 1187 |
|
|
* FIXME(eric) - these are empty stubs for the moment. I need to re-implement
|
| 1188 |
|
|
* host blocking from scratch. The theory is that hosts that wish to block
|
| 1189 |
|
|
* will register/deregister using these functions instead of the old way
|
| 1190 |
|
|
* of setting the wish_block flag.
|
| 1191 |
|
|
*
|
| 1192 |
|
|
* The details of the implementation remain to be settled, however the
|
| 1193 |
|
|
* stubs are here now so that the actual drivers will properly compile.
|
| 1194 |
|
|
*/
|
| 1195 |
|
|
void scsi_register_blocked_host(struct Scsi_Host * SHpnt)
|
| 1196 |
|
|
{
|
| 1197 |
|
|
}
|
| 1198 |
|
|
|
| 1199 |
|
|
void scsi_deregister_blocked_host(struct Scsi_Host * SHpnt)
|
| 1200 |
|
|
{
|
| 1201 |
|
|
}
|
