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scsi: make asynchronous aborts mandatory

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There hasn't been any reports for HBAs where asynchronous abort
would not work, so we should make it mandatory and remove
the fallback.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Hannes Reinecke 2017-04-06 15:36:35 +02:00 committed by Martin K. Petersen
parent 2171b6d08b
commit a06586325f
5 changed files with 15 additions and 94 deletions
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18
Documentation/scsi/scsi_eh.txt
View File

@ -70,7 +70,7 @@ with the command.
scmd is requeued to blk queue.
- otherwise
scsi_eh_scmd_add(scmd, 0) is invoked for the command. See
scsi_eh_scmd_add(scmd) is invoked for the command. See
[1-3] for details of this function.
@ -103,9 +103,7 @@ function
eh_timed_out() callback did not handle the command.
Step #2 is taken.
2. If the host supports asynchronous completion (as indicated by the
no_async_abort setting in the host template) scsi_abort_command()
is invoked to schedule an asynchrous abort.
2. scsi_abort_command() is invoked to schedule an asynchrous abort.
Asynchronous abort are not invoked for commands which the
SCSI_EH_ABORT_SCHEDULED flag is set (this indicates that the command
already had been aborted once, and this is a retry which failed),
@ -127,16 +125,13 @@ function
scmds enter EH via scsi_eh_scmd_add(), which does the following.
1. Turns on scmd->eh_eflags as requested. It's 0 for error
completions and SCSI_EH_CANCEL_CMD for timeouts.
1. Links scmd->eh_entry to shost->eh_cmd_q
2. Links scmd->eh_entry to shost->eh_cmd_q
2. Sets SHOST_RECOVERY bit in shost->shost_state
3. Sets SHOST_RECOVERY bit in shost->shost_state
3. Increments shost->host_failed
4. Increments shost->host_failed
5. Wakes up SCSI EH thread if shost->host_busy == shost->host_failed
4. Wakes up SCSI EH thread if shost->host_busy == shost->host_failed
As can be seen above, once any scmd is added to shost->eh_cmd_q,
SHOST_RECOVERY shost_state bit is turned on. This prevents any new
@ -252,7 +247,6 @@ scmd->allowed.
1. Error completion / time out
ACTION: scsi_eh_scmd_add() is invoked for scmd
- set scmd->eh_eflags
- add scmd to shost->eh_cmd_q
- set SHOST_RECOVERY
- shost->host_failed++

81
drivers/scsi/scsi_error.c
View File

@ -162,7 +162,7 @@ scmd_eh_abort_handler(struct work_struct *work)
}
}
scsi_eh_scmd_add(scmd, 0);
scsi_eh_scmd_add(scmd);
}
/**
@ -221,9 +221,8 @@ static void scsi_eh_reset(struct scsi_cmnd *scmd)
/**
* scsi_eh_scmd_add - add scsi cmd to error handling.
* @scmd: scmd to run eh on.
* @eh_flag: optional SCSI_EH flag.
*/
void scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
void scsi_eh_scmd_add(struct scsi_cmnd *scmd)
{
struct Scsi_Host *shost = scmd->device->host;
unsigned long flags;
@ -239,9 +238,6 @@ void scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
if (shost->eh_deadline != -1 && !shost->last_reset)
shost->last_reset = jiffies;
if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED)
eh_flag &= ~SCSI_EH_CANCEL_CMD;
scmd->eh_eflags |= eh_flag;
scsi_eh_reset(scmd);
list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
shost->host_failed++;
@ -275,10 +271,9 @@ enum blk_eh_timer_return scsi_times_out(struct request *req)
rtn = host->hostt->eh_timed_out(scmd);
if (rtn == BLK_EH_NOT_HANDLED) {
if (host->hostt->no_async_abort ||
scsi_abort_command(scmd) != SUCCESS) {
if (scsi_abort_command(scmd) != SUCCESS) {
set_host_byte(scmd, DID_TIME_OUT);
scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD);
scsi_eh_scmd_add(scmd);
}
}
@ -331,7 +326,7 @@ static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
list_for_each_entry(scmd, work_q, eh_entry) {
if (scmd->device == sdev) {
++total_failures;
if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD)
if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED)
++cmd_cancel;
else
++cmd_failed;
@ -1154,8 +1149,7 @@ int scsi_eh_get_sense(struct list_head *work_q,
* should not get sense.
*/
list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
(scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) ||
if ((scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) ||
SCSI_SENSE_VALID(scmd))
continue;
@ -1295,61 +1289,6 @@ static int scsi_eh_test_devices(struct list_head *cmd_list,
return list_empty(work_q);
}
/**
* scsi_eh_abort_cmds - abort pending commands.
* @work_q: &list_head for pending commands.
* @done_q: &list_head for processed commands.
*
* Decription:
* Try and see whether or not it makes sense to try and abort the
* running command. This only works out to be the case if we have one
* command that has timed out. If the command simply failed, it makes
* no sense to try and abort the command, since as far as the shost
* adapter is concerned, it isn't running.
*/
static int scsi_eh_abort_cmds(struct list_head *work_q,
struct list_head *done_q)
{
struct scsi_cmnd *scmd, *next;
LIST_HEAD(check_list);
int rtn;
struct Scsi_Host *shost;
list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
continue;
shost = scmd->device->host;
if (scsi_host_eh_past_deadline(shost)) {
list_splice_init(&check_list, work_q);
SCSI_LOG_ERROR_RECOVERY(3,
scmd_printk(KERN_INFO, scmd,
"%s: skip aborting cmd, past eh deadline\n",
current->comm));
return list_empty(work_q);
}
SCSI_LOG_ERROR_RECOVERY(3,
scmd_printk(KERN_INFO, scmd,
"%s: aborting cmd\n", current->comm));
rtn = scsi_try_to_abort_cmd(shost->hostt, scmd);
if (rtn == FAILED) {
SCSI_LOG_ERROR_RECOVERY(3,
scmd_printk(KERN_INFO, scmd,
"%s: aborting cmd failed\n",
current->comm));
list_splice_init(&check_list, work_q);
return list_empty(work_q);
}
scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
if (rtn == FAST_IO_FAIL)
scsi_eh_finish_cmd(scmd, done_q);
else
list_move_tail(&scmd->eh_entry, &check_list);
}
return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
}
/**
* scsi_eh_try_stu - Send START_UNIT to device.
* @scmd: &scsi_cmnd to send START_UNIT
@ -1692,11 +1631,6 @@ static void scsi_eh_offline_sdevs(struct list_head *work_q,
sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
"not ready after error recovery\n");
scsi_device_set_state(scmd->device, SDEV_OFFLINE);
if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
/*
* FIXME: Handle lost cmds.
*/
}
scsi_eh_finish_cmd(scmd, done_q);
}
return;
@ -2140,8 +2074,7 @@ static void scsi_unjam_host(struct Scsi_Host *shost)
SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
spin_lock_irqsave(shost->host_lock, flags);
if (shost->eh_deadline != -1)

2
drivers/scsi/scsi_lib.c
View File

@ -1593,7 +1593,7 @@ static void scsi_softirq_done(struct request *rq)
scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
break;
default:
scsi_eh_scmd_add(cmd, 0);
scsi_eh_scmd_add(cmd);
break;
}
}

3
drivers/scsi/scsi_priv.h
View File

@ -18,7 +18,6 @@ struct scsi_nl_hdr;
/*
* Scsi Error Handler Flags
*/
#define SCSI_EH_CANCEL_CMD 0x0001 /* Cancel this cmd */
#define SCSI_EH_ABORT_SCHEDULED 0x0002 /* Abort has been scheduled */
#define SCSI_SENSE_VALID(scmd) \
@ -72,7 +71,7 @@ extern enum blk_eh_timer_return scsi_times_out(struct request *req);
extern int scsi_error_handler(void *host);
extern int scsi_decide_disposition(struct scsi_cmnd *cmd);
extern void scsi_eh_wakeup(struct Scsi_Host *shost);
extern void scsi_eh_scmd_add(struct scsi_cmnd *, int);
extern void scsi_eh_scmd_add(struct scsi_cmnd *);
void scsi_eh_ready_devs(struct Scsi_Host *shost,
struct list_head *work_q,
struct list_head *done_q);

5
include/scsi/scsi_host.h
View File

@ -451,11 +451,6 @@ struct scsi_host_template {
/* True if the controller does not support WRITE SAME */
unsigned no_write_same:1;
/*
* True if asynchronous aborts are not supported
*/
unsigned no_async_abort:1;
/*
* Countdown for host blocking with no commands outstanding.
*/