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[SCSI] use a completion in scsi_send_eh_cmnd

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scsi_send_eh_cmnd currently uses a semaphore and an overload of eh_timer
to either get a completion for a command for a timeout.
Switch to using a completion and wait_for_completion_timeout to simply
the code and not having to deal with the races ourselves.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
This commit is contained in:
Christoph Hellwig 2005-10-31 18:49:52 +01:00 committed by James Bottomley
parent 262eef663b
commit 7dfdc9a52b
3 changed files with 32 additions and 81 deletions
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107
drivers/scsi/scsi_error.c
View file

@ -416,44 +416,16 @@ static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
return FAILED;
}
/**
* scsi_eh_times_out - timeout function for error handling.
* @scmd: Cmd that is timing out.
*
* Notes:
* During error handling, the kernel thread will be sleeping waiting
* for some action to complete on the device. our only job is to
* record that it timed out, and to wake up the thread.
**/
static void scsi_eh_times_out(struct scsi_cmnd *scmd)
{
scmd->eh_eflags |= SCSI_EH_REC_TIMEOUT;
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd:%p\n", __FUNCTION__,
scmd));
up(scmd->device->host->eh_action);
}
/**
* scsi_eh_done - Completion function for error handling.
* @scmd: Cmd that is done.
**/
static void scsi_eh_done(struct scsi_cmnd *scmd)
{
/*
* if the timeout handler is already running, then just set the
* flag which says we finished late, and return. we have no
* way of stopping the timeout handler from running, so we must
* always defer to it.
*/
if (del_timer(&scmd->eh_timeout)) {
scmd->request->rq_status = RQ_SCSI_DONE;
SCSI_LOG_ERROR_RECOVERY(3, printk("%s scmd: %p result: %x\n",
__FUNCTION__, scmd, scmd->result));
up(scmd->device->host->eh_action);
}
SCSI_LOG_ERROR_RECOVERY(3,
printk("%s scmd: %p result: %x\n",
__FUNCTION__, scmd, scmd->result));
complete(scmd->device->host->eh_action);
}
/**
@ -461,10 +433,6 @@ static void scsi_eh_done(struct scsi_cmnd *scmd)
* @scmd: SCSI Cmd to send.
* @timeout: Timeout for cmd.
*
* Notes:
* The initialization of the structures is quite a bit different in
* this case, and furthermore, there is a different completion handler
* vs scsi_dispatch_cmd.
* Return value:
* SUCCESS or FAILED or NEEDS_RETRY
**/
@ -472,24 +440,16 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, int timeout)
{
struct scsi_device *sdev = scmd->device;
struct Scsi_Host *shost = sdev->host;
DECLARE_MUTEX_LOCKED(sem);
DECLARE_COMPLETION(done);
unsigned long timeleft;
unsigned long flags;
int rtn = SUCCESS;
int rtn;
/*
* we will use a queued command if possible, otherwise we will
* emulate the queuing and calling of completion function ourselves.
*/
if (sdev->scsi_level <= SCSI_2)
scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
(sdev->lun << 5 & 0xe0);
scsi_add_timer(scmd, timeout, scsi_eh_times_out);
/*
* set up the semaphore so we wait for the command to complete.
*/
shost->eh_action = &sem;
shost->eh_action = &done;
scmd->request->rq_status = RQ_SCSI_BUSY;
spin_lock_irqsave(shost->host_lock, flags);
@ -497,47 +457,29 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, int timeout)
shost->hostt->queuecommand(scmd, scsi_eh_done);
spin_unlock_irqrestore(shost->host_lock, flags);
down(&sem);
scsi_log_completion(scmd, SUCCESS);
timeleft = wait_for_completion_timeout(&done, timeout);
scmd->request->rq_status = RQ_SCSI_DONE;
shost->eh_action = NULL;
/*
* see if timeout. if so, tell the host to forget about it.
* in other words, we don't want a callback any more.
*/
if (scmd->eh_eflags & SCSI_EH_REC_TIMEOUT) {
scmd->eh_eflags &= ~SCSI_EH_REC_TIMEOUT;
scsi_log_completion(scmd, SUCCESS);
/*
* as far as the low level driver is
* concerned, this command is still active, so
* we must give the low level driver a chance
* to abort it. (db)
*
* FIXME(eric) - we are not tracking whether we could
* abort a timed out command or not. not sure how
* we should treat them differently anyways.
*/
if (shost->hostt->eh_abort_handler)
shost->hostt->eh_abort_handler(scmd);
scmd->request->rq_status = RQ_SCSI_DONE;
rtn = FAILED;
}
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd: %p, rtn:%x\n",
__FUNCTION__, scmd, rtn));
SCSI_LOG_ERROR_RECOVERY(3,
printk("%s: scmd: %p, timeleft: %ld\n",
__FUNCTION__, scmd, timeleft));
/*
* now examine the actual status codes to see whether the command
* actually did complete normally.
* If there is time left scsi_eh_done got called, and we will
* examine the actual status codes to see whether the command
* actually did complete normally, else tell the host to forget
* about this command.
*/
if (rtn == SUCCESS) {
if (timeleft) {
rtn = scsi_eh_completed_normally(scmd);
SCSI_LOG_ERROR_RECOVERY(3,
printk("%s: scsi_eh_completed_normally %x\n",
__FUNCTION__, rtn));
switch (rtn) {
case SUCCESS:
case NEEDS_RETRY:
@ -547,6 +489,15 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, int timeout)
rtn = FAILED;
break;
}
} else {
/*
* FIXME(eric) - we are not tracking whether we could
* abort a timed out command or not. not sure how
* we should treat them differently anyways.
*/
if (shost->hostt->eh_abort_handler)
shost->hostt->eh_abort_handler(scmd);
rtn = FAILED;
}
return rtn;

1
drivers/scsi/scsi_priv.h
View file

@ -22,7 +22,6 @@ struct Scsi_Host;
* Scsi Error Handler Flags
*/
#define SCSI_EH_CANCEL_CMD 0x0001 /* Cancel this cmd */
#define SCSI_EH_REC_TIMEOUT 0x0002 /* EH retry timed out */
#define SCSI_SENSE_VALID(scmd) \
(((scmd)->sense_buffer[0] & 0x70) == 0x70)

5
include/scsi/scsi_host.h
View file

@ -7,6 +7,7 @@
#include <linux/workqueue.h>
struct block_device;
struct completion;
struct module;
struct scsi_cmnd;
struct scsi_device;
@ -467,8 +468,8 @@ struct Scsi_Host {
struct list_head eh_cmd_q;
struct task_struct * ehandler; /* Error recovery thread. */
struct semaphore * eh_action; /* Wait for specific actions on the
host. */
struct completion * eh_action; /* Wait for specific actions on the
host. */
wait_queue_head_t host_wait;
struct scsi_host_template *hostt;
struct scsi_transport_template *transportt;