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[/] [or1k/] [trunk/] [rc203soc/] [sw/] [uClinux/] [fs/] [autofs/] [waitq.c] - Blame information for rev 1777

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Line No. Rev Author Line
1 1628 jcastillo
/* -*- linux-c -*- --------------------------------------------------------- *
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 *
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 * linux/fs/autofs/waitq.c
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 *
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 *  Copyright 1997 Transmeta Corporation -- All Rights Reserved
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 *
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 * This file is part of the Linux kernel and is made available under
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 * the terms of the GNU General Public License, version 2, or at your
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 * option, any later version, incorporated herein by reference.
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 *
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 * ------------------------------------------------------------------------- */
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#include <linux/malloc.h>
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#include <linux/sched.h>
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#include <linux/signal.h>
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#include <linux/file.h>
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#include "autofs_i.h"
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/* We make this a static variable rather than a part of the superblock; it
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   is better if we don't reassign numbers easily even across filesystems */
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static int autofs_next_wait_queue = 1;
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void autofs_catatonic_mode(struct autofs_sb_info *sbi)
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{
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        struct autofs_wait_queue *wq, *nwq;
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        DPRINTK(("autofs: entering catatonic mode\n"));
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        sbi->catatonic = 1;
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        wq = sbi->queues;
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        sbi->queues = NULL;     /* Erase all wait queues */
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        while ( wq ) {
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                nwq = wq->next;
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                wq->status = -ENOENT; /* Magic is gone - report failure */
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                kfree(wq->name);
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                wq->name = NULL;
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                wake_up(&wq->queue);
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                wq = nwq;
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        }
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        fput(sbi->pipe, sbi->pipe->f_inode);    /* Close the pipe */
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}
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static int autofs_write(struct file *file, const void *addr, int bytes)
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{
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        unsigned short fs;
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        unsigned long old_signal;
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        const char *data = (const char *)addr;
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        int written = 0;
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        /** WARNING: this is not safe for writing more than PIPE_BUF bytes! **/
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        /* Save pointer to user space and point back to kernel space */
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        fs = get_fs();
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        set_fs(KERNEL_DS);
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        old_signal = current->signal;
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        while ( bytes && (written = file->f_op->write(file->f_inode,file,data,bytes)) > 0 ) {
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                data += written;
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                bytes -= written;
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        }
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        if ( written == -EPIPE && !(old_signal & (1 << (SIGPIPE-1))) ) {
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                /* Keep the currently executing process from receiving a
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                   SIGPIPE unless it was already supposed to get one */
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                current->signal &= ~(1 << (SIGPIPE-1));
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        }
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        set_fs(fs);
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        return (bytes > 0);
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}
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static void autofs_notify_daemon(struct autofs_sb_info *sbi, struct autofs_wait_queue *wq)
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{
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        struct autofs_packet_missing pkt;
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        DPRINTK(("autofs_wait: wait id = 0x%08lx, name = ", wq->wait_queue_token));
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        autofs_say(wq->name,wq->len);
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        memset(&pkt,0,sizeof pkt); /* For security reasons */
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        pkt.hdr.proto_version = AUTOFS_PROTO_VERSION;
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        pkt.hdr.type = autofs_ptype_missing;
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        pkt.wait_queue_token = wq->wait_queue_token;
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        pkt.len = wq->len;
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        memcpy(pkt.name, wq->name, pkt.len);
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        pkt.name[pkt.len] = '\0';
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        if ( autofs_write(sbi->pipe,&pkt,sizeof(struct autofs_packet_missing)) )
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                autofs_catatonic_mode(sbi);
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}
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int autofs_wait(struct autofs_sb_info *sbi, autofs_hash_t hash, const char *name, int len)
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{
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        struct autofs_wait_queue *wq;
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        int status;
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        for ( wq = sbi->queues ; wq ; wq = wq->next ) {
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                if ( wq->hash == hash &&
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                     wq->len == len &&
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                     wq->name && !memcmp(wq->name,name,len) )
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                        break;
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        }
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        if ( !wq ) {
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                /* Create a new wait queue */
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                wq = kmalloc(sizeof(struct autofs_wait_queue),GFP_KERNEL);
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                if ( !wq )
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                        return -ENOMEM;
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                wq->name = kmalloc(len,GFP_KERNEL);
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                if ( !wq->name ) {
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                        kfree(wq);
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                        return -ENOMEM;
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                }
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                wq->wait_queue_token = autofs_next_wait_queue++;
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                init_waitqueue(&wq->queue);
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                wq->hash = hash;
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                wq->len = len;
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                wq->status = -EINTR; /* Status return if interrupted */
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                memcpy(wq->name, name, len);
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                wq->next = sbi->queues;
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                sbi->queues = wq;
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                /* autofs_notify_daemon() may block */
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                wq->wait_ctr = 2;
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                autofs_notify_daemon(sbi,wq);
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        } else
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                wq->wait_ctr++;
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        if ( wq->name ) {
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                /* wq->name is NULL if and only if the lock is released */
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                interruptible_sleep_on(&wq->queue);
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        } else {
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                DPRINTK(("autofs_wait: skipped sleeping\n"));
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        }
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        status = wq->status;
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        if ( ! --wq->wait_ctr ) /* Are we the last process to need status? */
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                kfree(wq);
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        return status;
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}
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int autofs_wait_release(struct autofs_sb_info *sbi, unsigned long wait_queue_token, int status)
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{
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        struct autofs_wait_queue *wq, **wql;
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        for ( wql = &sbi->queues ; (wq = *wql) ; wql = &wq->next ) {
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                if ( wq->wait_queue_token == wait_queue_token )
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                        break;
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        }
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        if ( !wq )
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                return -EINVAL;
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        *wql = wq->next;        /* Unlink from chain */
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        kfree(wq->name);
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        wq->name = NULL;        /* Do not wait on this queue */
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        wq->status = status;
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        if ( ! --wq->wait_ctr ) /* Is anyone still waiting for this guy? */
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                kfree(wq);
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        else
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                wake_up(&wq->queue);
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        return 0;
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}
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