| 1 |
1275 |
phoenix |
/*
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* scsi_dma.c Copyright (C) 2000 Eric Youngdale
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*
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* mid-level SCSI DMA bounce buffer allocator
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*
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*/
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#define __NO_VERSION__
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#include <linux/config.h>
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#include <linux/module.h>
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#include <linux/blk.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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#ifdef CONFIG_KMOD
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#include <linux/kmod.h>
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#endif
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/*
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* PAGE_SIZE must be a multiple of the sector size (512). True
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* for all reasonably recent architectures (even the VAX...).
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*/
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#define SECTOR_SIZE 512
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#define SECTORS_PER_PAGE (PAGE_SIZE/SECTOR_SIZE)
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#if SECTORS_PER_PAGE <= 8
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typedef unsigned char FreeSectorBitmap;
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#elif SECTORS_PER_PAGE <= 32
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typedef unsigned int FreeSectorBitmap;
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#else
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#error You lose.
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#endif
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/*
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* Used for access to internal allocator used for DMA safe buffers.
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*/
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static spinlock_t allocator_request_lock = SPIN_LOCK_UNLOCKED;
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static FreeSectorBitmap *dma_malloc_freelist = NULL;
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static int need_isa_bounce_buffers;
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static unsigned int dma_sectors = 0;
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unsigned int scsi_dma_free_sectors = 0;
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unsigned int scsi_need_isa_buffer = 0;
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static unsigned char **dma_malloc_pages = NULL;
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/*
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* Function: scsi_malloc
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*
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* Purpose: Allocate memory from the DMA-safe pool.
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*
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* Arguments: len - amount of memory we need.
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*
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* Lock status: No locks assumed to be held. This function is SMP-safe.
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*
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* Returns: Pointer to memory block.
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*
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* Notes: Prior to the new queue code, this function was not SMP-safe.
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* This function can only allocate in units of sectors
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* (i.e. 512 bytes).
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*
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* We cannot use the normal system allocator becuase we need
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* to be able to guarantee that we can process a complete disk
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* I/O request without touching the system allocator. Think
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* about it - if the system were heavily swapping, and tried to
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* write out a block of memory to disk, and the SCSI code needed
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* to allocate more memory in order to be able to write the
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* data to disk, you would wedge the system.
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*/
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void *scsi_malloc(unsigned int len)
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{
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unsigned int nbits, mask;
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unsigned long flags;
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int i, j;
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if (len % SECTOR_SIZE != 0 || len > PAGE_SIZE)
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return NULL;
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nbits = len >> 9;
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mask = (1 << nbits) - 1;
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spin_lock_irqsave(&allocator_request_lock, flags);
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for (i = 0; i < dma_sectors / SECTORS_PER_PAGE; i++)
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for (j = 0; j <= SECTORS_PER_PAGE - nbits; j++) {
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if ((dma_malloc_freelist[i] & (mask << j)) == 0) {
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dma_malloc_freelist[i] |= (mask << j);
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scsi_dma_free_sectors -= nbits;
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#ifdef DEBUG
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SCSI_LOG_MLQUEUE(3, printk("SMalloc: %d %p [From:%p]\n", len, dma_malloc_pages[i] + (j << 9)));
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printk("SMalloc: %d %p [From:%p]\n", len, dma_malloc_pages[i] + (j << 9));
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#endif
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spin_unlock_irqrestore(&allocator_request_lock, flags);
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return (void *) ((unsigned long) dma_malloc_pages[i] + (j << 9));
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}
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}
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spin_unlock_irqrestore(&allocator_request_lock, flags);
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return NULL; /* Nope. No more */
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}
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/*
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* Function: scsi_free
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*
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* Purpose: Free memory into the DMA-safe pool.
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*
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* Arguments: ptr - data block we are freeing.
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* len - size of block we are freeing.
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*
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* Lock status: No locks assumed to be held. This function is SMP-safe.
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*
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* Returns: Nothing
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*
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* Notes: This function *must* only be used to free memory
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* allocated from scsi_malloc().
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*
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* Prior to the new queue code, this function was not SMP-safe.
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* This function can only allocate in units of sectors
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* (i.e. 512 bytes).
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*/
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int scsi_free(void *obj, unsigned int len)
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{
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unsigned int page, sector, nbits, mask;
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unsigned long flags;
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#ifdef DEBUG
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unsigned long ret = 0;
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#ifdef __mips__
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__asm__ __volatile__("move\t%0,$31":"=r"(ret));
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#else
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ret = __builtin_return_address(0);
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#endif
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printk("scsi_free %p %d\n", obj, len);
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SCSI_LOG_MLQUEUE(3, printk("SFree: %p %d\n", obj, len));
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#endif
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spin_lock_irqsave(&allocator_request_lock, flags);
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for (page = 0; page < dma_sectors / SECTORS_PER_PAGE; page++) {
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unsigned long page_addr = (unsigned long) dma_malloc_pages[page];
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if ((unsigned long) obj >= page_addr &&
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(unsigned long) obj < page_addr + PAGE_SIZE) {
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sector = (((unsigned long) obj) - page_addr) >> 9;
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nbits = len >> 9;
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mask = (1 << nbits) - 1;
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if (sector + nbits > SECTORS_PER_PAGE)
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panic("scsi_free:Bad memory alignment");
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if ((dma_malloc_freelist[page] &
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(mask << sector)) != (mask << sector)) {
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#ifdef DEBUG
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printk("scsi_free(obj=%p, len=%d) called from %08lx\n",
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obj, len, ret);
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#endif
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panic("scsi_free:Trying to free unused memory");
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}
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scsi_dma_free_sectors += nbits;
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dma_malloc_freelist[page] &= ~(mask << sector);
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spin_unlock_irqrestore(&allocator_request_lock, flags);
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return 0;
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}
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}
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panic("scsi_free:Bad offset");
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}
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/*
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* Function: scsi_resize_dma_pool
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*
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* Purpose: Ensure that the DMA pool is sufficiently large to be
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* able to guarantee that we can always process I/O requests
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* without calling the system allocator.
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*
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* Arguments: None.
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*
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* Lock status: No locks assumed to be held. This function is SMP-safe.
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*
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* Returns: Nothing
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*
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* Notes: Prior to the new queue code, this function was not SMP-safe.
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* Go through the device list and recompute the most appropriate
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* size for the dma pool. Then grab more memory (as required).
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*/
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void scsi_resize_dma_pool(void)
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{
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int i, k;
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unsigned long size;
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unsigned long flags;
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struct Scsi_Host *shpnt;
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struct Scsi_Host *host = NULL;
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Scsi_Device *SDpnt;
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FreeSectorBitmap *new_dma_malloc_freelist = NULL;
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unsigned int new_dma_sectors = 0;
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unsigned int new_need_isa_buffer = 0;
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unsigned char **new_dma_malloc_pages = NULL;
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int out_of_space = 0;
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spin_lock_irqsave(&allocator_request_lock, flags);
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if (!scsi_hostlist) {
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/*
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* Free up the DMA pool.
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*/
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if (scsi_dma_free_sectors != dma_sectors)
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panic("SCSI DMA pool memory leak %d %d\n", scsi_dma_free_sectors, dma_sectors);
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for (i = 0; i < dma_sectors / SECTORS_PER_PAGE; i++)
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free_pages((unsigned long) dma_malloc_pages[i], 0);
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if (dma_malloc_pages)
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kfree((char *) dma_malloc_pages);
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dma_malloc_pages = NULL;
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if (dma_malloc_freelist)
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kfree((char *) dma_malloc_freelist);
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| 218 |
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dma_malloc_freelist = NULL;
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dma_sectors = 0;
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scsi_dma_free_sectors = 0;
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spin_unlock_irqrestore(&allocator_request_lock, flags);
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return;
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}
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/* Next, check to see if we need to extend the DMA buffer pool */
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new_dma_sectors = 2 * SECTORS_PER_PAGE; /* Base value we use */
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| 228 |
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if (__pa(high_memory) - 1 > ISA_DMA_THRESHOLD)
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need_isa_bounce_buffers = 1;
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else
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need_isa_bounce_buffers = 0;
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| 233 |
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if (scsi_devicelist)
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for (shpnt = scsi_hostlist; shpnt; shpnt = shpnt->next)
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new_dma_sectors += SECTORS_PER_PAGE; /* Increment for each host */
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| 237 |
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for (host = scsi_hostlist; host; host = host->next) {
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| 238 |
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for (SDpnt = host->host_queue; SDpnt; SDpnt = SDpnt->next) {
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| 239 |
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/*
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| 240 |
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* sd and sr drivers allocate scatterlists.
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| 241 |
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* sr drivers may allocate for each command 1x2048 or 2x1024 extra
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| 242 |
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* buffers for 2k sector size and 1k fs.
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| 243 |
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* sg driver allocates buffers < 4k.
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| 244 |
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* st driver does not need buffers from the dma pool.
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| 245 |
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* estimate 4k buffer/command for devices of unknown type (should panic).
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| 246 |
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*/
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| 247 |
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if (SDpnt->type == TYPE_WORM || SDpnt->type == TYPE_ROM ||
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| 248 |
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SDpnt->type == TYPE_DISK || SDpnt->type == TYPE_MOD) {
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| 249 |
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int nents = host->sg_tablesize;
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| 250 |
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#ifdef DMA_CHUNK_SIZE
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| 251 |
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/* If the architecture does DMA sg merging, make sure
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| 252 |
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we count with at least 64 entries even for HBAs
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| 253 |
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which handle very few sg entries. */
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| 254 |
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if (nents < 64) nents = 64;
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| 255 |
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#endif
|
| 256 |
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new_dma_sectors += ((nents *
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| 257 |
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sizeof(struct scatterlist) + 511) >> 9) *
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| 258 |
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SDpnt->queue_depth;
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| 259 |
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if (SDpnt->type == TYPE_WORM || SDpnt->type == TYPE_ROM)
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| 260 |
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new_dma_sectors += (2048 >> 9) * SDpnt->queue_depth;
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| 261 |
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} else if (SDpnt->type == TYPE_SCANNER ||
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| 262 |
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SDpnt->type == TYPE_PRINTER ||
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| 263 |
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SDpnt->type == TYPE_PROCESSOR ||
|
| 264 |
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SDpnt->type == TYPE_COMM ||
|
| 265 |
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SDpnt->type == TYPE_MEDIUM_CHANGER ||
|
| 266 |
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SDpnt->type == TYPE_ENCLOSURE) {
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| 267 |
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new_dma_sectors += (4096 >> 9) * SDpnt->queue_depth;
|
| 268 |
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} else {
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| 269 |
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if (SDpnt->type != TYPE_TAPE) {
|
| 270 |
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printk("resize_dma_pool: unknown device type %d\n", SDpnt->type);
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| 271 |
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new_dma_sectors += (4096 >> 9) * SDpnt->queue_depth;
|
| 272 |
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}
|
| 273 |
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}
|
| 274 |
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|
| 275 |
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if (host->unchecked_isa_dma &&
|
| 276 |
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need_isa_bounce_buffers &&
|
| 277 |
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SDpnt->type != TYPE_TAPE) {
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| 278 |
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new_dma_sectors += (PAGE_SIZE >> 9) * host->sg_tablesize *
|
| 279 |
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SDpnt->queue_depth;
|
| 280 |
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new_need_isa_buffer++;
|
| 281 |
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}
|
| 282 |
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}
|
| 283 |
|
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}
|
| 284 |
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| 285 |
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#ifdef DEBUG_INIT
|
| 286 |
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printk("resize_dma_pool: needed dma sectors = %d\n", new_dma_sectors);
|
| 287 |
|
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#endif
|
| 288 |
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|
| 289 |
|
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/* limit DMA memory to 32MB: */
|
| 290 |
|
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new_dma_sectors = (new_dma_sectors + 15) & 0xfff0;
|
| 291 |
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|
| 292 |
|
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/*
|
| 293 |
|
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* We never shrink the buffers - this leads to
|
| 294 |
|
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* race conditions that I would rather not even think
|
| 295 |
|
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* about right now.
|
| 296 |
|
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*/
|
| 297 |
|
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#if 0 /* Why do this? No gain and risks out_of_space */
|
| 298 |
|
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if (new_dma_sectors < dma_sectors)
|
| 299 |
|
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new_dma_sectors = dma_sectors;
|
| 300 |
|
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#endif
|
| 301 |
|
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if (new_dma_sectors <= dma_sectors) {
|
| 302 |
|
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spin_unlock_irqrestore(&allocator_request_lock, flags);
|
| 303 |
|
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return; /* best to quit while we are in front */
|
| 304 |
|
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}
|
| 305 |
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|
| 306 |
|
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for (k = 0; k < 20; ++k) { /* just in case */
|
| 307 |
|
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out_of_space = 0;
|
| 308 |
|
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size = (new_dma_sectors / SECTORS_PER_PAGE) *
|
| 309 |
|
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sizeof(FreeSectorBitmap);
|
| 310 |
|
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new_dma_malloc_freelist = (FreeSectorBitmap *)
|
| 311 |
|
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kmalloc(size, GFP_ATOMIC);
|
| 312 |
|
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if (new_dma_malloc_freelist) {
|
| 313 |
|
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memset(new_dma_malloc_freelist, 0, size);
|
| 314 |
|
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size = (new_dma_sectors / SECTORS_PER_PAGE) *
|
| 315 |
|
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sizeof(*new_dma_malloc_pages);
|
| 316 |
|
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new_dma_malloc_pages = (unsigned char **)
|
| 317 |
|
|
kmalloc(size, GFP_ATOMIC);
|
| 318 |
|
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if (!new_dma_malloc_pages) {
|
| 319 |
|
|
size = (new_dma_sectors / SECTORS_PER_PAGE) *
|
| 320 |
|
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sizeof(FreeSectorBitmap);
|
| 321 |
|
|
kfree((char *) new_dma_malloc_freelist);
|
| 322 |
|
|
out_of_space = 1;
|
| 323 |
|
|
} else {
|
| 324 |
|
|
memset(new_dma_malloc_pages, 0, size);
|
| 325 |
|
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}
|
| 326 |
|
|
} else
|
| 327 |
|
|
out_of_space = 1;
|
| 328 |
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|
| 329 |
|
|
if ((!out_of_space) && (new_dma_sectors > dma_sectors)) {
|
| 330 |
|
|
for (i = dma_sectors / SECTORS_PER_PAGE;
|
| 331 |
|
|
i < new_dma_sectors / SECTORS_PER_PAGE; i++) {
|
| 332 |
|
|
new_dma_malloc_pages[i] = (unsigned char *)
|
| 333 |
|
|
__get_free_pages(GFP_ATOMIC | GFP_DMA, 0);
|
| 334 |
|
|
if (!new_dma_malloc_pages[i])
|
| 335 |
|
|
break;
|
| 336 |
|
|
}
|
| 337 |
|
|
if (i != new_dma_sectors / SECTORS_PER_PAGE) { /* clean up */
|
| 338 |
|
|
int k = i;
|
| 339 |
|
|
|
| 340 |
|
|
out_of_space = 1;
|
| 341 |
|
|
for (i = 0; i < k; ++i)
|
| 342 |
|
|
free_pages((unsigned long) new_dma_malloc_pages[i], 0);
|
| 343 |
|
|
}
|
| 344 |
|
|
}
|
| 345 |
|
|
if (out_of_space) { /* try scaling down new_dma_sectors request */
|
| 346 |
|
|
printk("scsi::resize_dma_pool: WARNING, dma_sectors=%u, "
|
| 347 |
|
|
"wanted=%u, scaling\n", dma_sectors, new_dma_sectors);
|
| 348 |
|
|
if (new_dma_sectors < (8 * SECTORS_PER_PAGE))
|
| 349 |
|
|
break; /* pretty well hopeless ... */
|
| 350 |
|
|
new_dma_sectors = (new_dma_sectors * 3) / 4;
|
| 351 |
|
|
new_dma_sectors = (new_dma_sectors + 15) & 0xfff0;
|
| 352 |
|
|
if (new_dma_sectors <= dma_sectors)
|
| 353 |
|
|
break; /* stick with what we have got */
|
| 354 |
|
|
} else
|
| 355 |
|
|
break; /* found space ... */
|
| 356 |
|
|
} /* end of for loop */
|
| 357 |
|
|
if (out_of_space) {
|
| 358 |
|
|
spin_unlock_irqrestore(&allocator_request_lock, flags);
|
| 359 |
|
|
scsi_need_isa_buffer = new_need_isa_buffer; /* some useful info */
|
| 360 |
|
|
printk(" WARNING, not enough memory, pool not expanded\n");
|
| 361 |
|
|
return;
|
| 362 |
|
|
}
|
| 363 |
|
|
/* When we dick with the actual DMA list, we need to
|
| 364 |
|
|
* protect things
|
| 365 |
|
|
*/
|
| 366 |
|
|
if (dma_malloc_freelist) {
|
| 367 |
|
|
size = (dma_sectors / SECTORS_PER_PAGE) * sizeof(FreeSectorBitmap);
|
| 368 |
|
|
memcpy(new_dma_malloc_freelist, dma_malloc_freelist, size);
|
| 369 |
|
|
kfree((char *) dma_malloc_freelist);
|
| 370 |
|
|
}
|
| 371 |
|
|
dma_malloc_freelist = new_dma_malloc_freelist;
|
| 372 |
|
|
|
| 373 |
|
|
if (dma_malloc_pages) {
|
| 374 |
|
|
size = (dma_sectors / SECTORS_PER_PAGE) * sizeof(*dma_malloc_pages);
|
| 375 |
|
|
memcpy(new_dma_malloc_pages, dma_malloc_pages, size);
|
| 376 |
|
|
kfree((char *) dma_malloc_pages);
|
| 377 |
|
|
}
|
| 378 |
|
|
scsi_dma_free_sectors += new_dma_sectors - dma_sectors;
|
| 379 |
|
|
dma_malloc_pages = new_dma_malloc_pages;
|
| 380 |
|
|
dma_sectors = new_dma_sectors;
|
| 381 |
|
|
scsi_need_isa_buffer = new_need_isa_buffer;
|
| 382 |
|
|
|
| 383 |
|
|
spin_unlock_irqrestore(&allocator_request_lock, flags);
|
| 384 |
|
|
|
| 385 |
|
|
#ifdef DEBUG_INIT
|
| 386 |
|
|
printk("resize_dma_pool: dma free sectors = %d\n", scsi_dma_free_sectors);
|
| 387 |
|
|
printk("resize_dma_pool: dma sectors = %d\n", dma_sectors);
|
| 388 |
|
|
printk("resize_dma_pool: need isa buffers = %d\n", scsi_need_isa_buffer);
|
| 389 |
|
|
#endif
|
| 390 |
|
|
}
|
| 391 |
|
|
|
| 392 |
|
|
/*
|
| 393 |
|
|
* Function: scsi_init_minimal_dma_pool
|
| 394 |
|
|
*
|
| 395 |
|
|
* Purpose: Allocate a minimal (1-page) DMA pool.
|
| 396 |
|
|
*
|
| 397 |
|
|
* Arguments: None.
|
| 398 |
|
|
*
|
| 399 |
|
|
* Lock status: No locks assumed to be held. This function is SMP-safe.
|
| 400 |
|
|
*
|
| 401 |
|
|
* Returns: Nothing
|
| 402 |
|
|
*
|
| 403 |
|
|
* Notes:
|
| 404 |
|
|
*/
|
| 405 |
|
|
int scsi_init_minimal_dma_pool(void)
|
| 406 |
|
|
{
|
| 407 |
|
|
unsigned long size;
|
| 408 |
|
|
unsigned long flags;
|
| 409 |
|
|
int has_space = 0;
|
| 410 |
|
|
|
| 411 |
|
|
spin_lock_irqsave(&allocator_request_lock, flags);
|
| 412 |
|
|
|
| 413 |
|
|
dma_sectors = PAGE_SIZE / SECTOR_SIZE;
|
| 414 |
|
|
scsi_dma_free_sectors = dma_sectors;
|
| 415 |
|
|
/*
|
| 416 |
|
|
* Set up a minimal DMA buffer list - this will be used during scan_scsis
|
| 417 |
|
|
* in some cases.
|
| 418 |
|
|
*/
|
| 419 |
|
|
|
| 420 |
|
|
/* One bit per sector to indicate free/busy */
|
| 421 |
|
|
size = (dma_sectors / SECTORS_PER_PAGE) * sizeof(FreeSectorBitmap);
|
| 422 |
|
|
dma_malloc_freelist = (FreeSectorBitmap *)
|
| 423 |
|
|
kmalloc(size, GFP_ATOMIC);
|
| 424 |
|
|
if (dma_malloc_freelist) {
|
| 425 |
|
|
memset(dma_malloc_freelist, 0, size);
|
| 426 |
|
|
/* One pointer per page for the page list */
|
| 427 |
|
|
dma_malloc_pages = (unsigned char **) kmalloc(
|
| 428 |
|
|
(dma_sectors / SECTORS_PER_PAGE) * sizeof(*dma_malloc_pages),
|
| 429 |
|
|
GFP_ATOMIC);
|
| 430 |
|
|
if (dma_malloc_pages) {
|
| 431 |
|
|
memset(dma_malloc_pages, 0, size);
|
| 432 |
|
|
dma_malloc_pages[0] = (unsigned char *)
|
| 433 |
|
|
__get_free_pages(GFP_ATOMIC | GFP_DMA, 0);
|
| 434 |
|
|
if (dma_malloc_pages[0])
|
| 435 |
|
|
has_space = 1;
|
| 436 |
|
|
}
|
| 437 |
|
|
}
|
| 438 |
|
|
if (!has_space) {
|
| 439 |
|
|
if (dma_malloc_freelist) {
|
| 440 |
|
|
kfree((char *) dma_malloc_freelist);
|
| 441 |
|
|
if (dma_malloc_pages)
|
| 442 |
|
|
kfree((char *) dma_malloc_pages);
|
| 443 |
|
|
}
|
| 444 |
|
|
spin_unlock_irqrestore(&allocator_request_lock, flags);
|
| 445 |
|
|
printk("scsi::init_module: failed, out of memory\n");
|
| 446 |
|
|
return 1;
|
| 447 |
|
|
}
|
| 448 |
|
|
|
| 449 |
|
|
spin_unlock_irqrestore(&allocator_request_lock, flags);
|
| 450 |
|
|
return 0;
|
| 451 |
|
|
}
|
