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authorHannes Reinecke <hare@suse.de>2013-11-11 13:44:54 +0100
committerJens Axboe <axboe@fb.com>2015-04-02 12:12:26 -0600
commitae9a5d93e5272020f103324c1d4b22ed9f6cde75 (patch)
tree5c9edb13653abc9a62cd0d3ac761e0c148fb1ffd
parent3c2ea47f6127cbc631cb2399bea1ed56be3b93e8 (diff)
improved eh timeout handler
When a command runs into a timeout we need to send an 'ABORT TASK' TMF. This is typically done by the 'eh_abort_handler' LLDD callback. Conceptually, however, this function is a normal SCSI command, so there is no need to enter the error handler. This patch implements a new scsi_abort_command() function which invokes an asynchronous function scsi_eh_abort_handler() to abort the commands via the usual 'eh_abort_handler'. If abort succeeds the command is either retried or terminated, depending on the number of allowed retries. However, 'eh_eflags' records the abort, so if the retry would fail again the command is pushed onto the error handler without trying to abort it (again); it'll be cleared up from SCSI EH. [hare: smatch detected stray switch fixed] Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
-rw-r--r--drivers/scsi/hosts.c14
-rw-r--r--drivers/scsi/scsi.c3
-rw-r--r--drivers/scsi/scsi_error.c151
-rw-r--r--drivers/scsi/scsi_priv.h2
-rw-r--r--include/scsi/scsi_cmnd.h1
-rw-r--r--include/scsi/scsi_host.h10
6 files changed, 167 insertions, 14 deletions
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 542cb508db5b..264023c607ed 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -169,6 +169,7 @@ void scsi_remove_host(struct Scsi_Host *shost)
spin_unlock_irqrestore(shost->host_lock, flags);
scsi_autopm_get_host(shost);
+ flush_workqueue(shost->tmf_work_q);
scsi_forget_host(shost);
mutex_unlock(&shost->scan_mutex);
scsi_proc_host_rm(shost);
@@ -294,6 +295,8 @@ static void scsi_host_dev_release(struct device *dev)
scsi_proc_hostdir_rm(shost->hostt);
+ if (shost->tmf_work_q)
+ destroy_workqueue(shost->tmf_work_q);
if (shost->ehandler)
kthread_stop(shost->ehandler);
if (shost->work_q)
@@ -360,7 +363,6 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
INIT_LIST_HEAD(&shost->eh_cmd_q);
INIT_LIST_HEAD(&shost->starved_list);
init_waitqueue_head(&shost->host_wait);
-
mutex_init(&shost->scan_mutex);
/*
@@ -444,9 +446,19 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
goto fail_kfree;
}
+ shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
+ WQ_UNBOUND | WQ_MEM_RECLAIM,
+ 1, shost->host_no);
+ if (!shost->tmf_work_q) {
+ printk(KERN_WARNING "scsi%d: failed to create tmf workq\n",
+ shost->host_no);
+ goto fail_kthread;
+ }
scsi_proc_hostdir_add(shost->hostt);
return shost;
+ fail_kthread:
+ kthread_stop(shost->ehandler);
fail_kfree:
kfree(shost);
return NULL;
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index fab2c2a10910..a079d76b7bbf 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -297,6 +297,7 @@ struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
cmd->device = dev;
INIT_LIST_HEAD(&cmd->list);
+ INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
spin_lock_irqsave(&dev->list_lock, flags);
list_add_tail(&cmd->list, &dev->cmd_list);
spin_unlock_irqrestore(&dev->list_lock, flags);
@@ -354,6 +355,8 @@ void scsi_put_command(struct scsi_cmnd *cmd)
list_del_init(&cmd->list);
spin_unlock_irqrestore(&cmd->device->list_lock, flags);
+ cancel_delayed_work(&cmd->abort_work);
+
__scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
}
EXPORT_SYMBOL(scsi_put_command);
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 094d23337844..38b703cda21f 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -55,6 +55,8 @@ static void scsi_eh_done(struct scsi_cmnd *scmd);
#define HOST_RESET_SETTLE_TIME (10)
static int scsi_eh_try_stu(struct scsi_cmnd *scmd);
+static int scsi_try_to_abort_cmd(struct scsi_host_template *,
+ struct scsi_cmnd *);
/* called with shost->host_lock held */
void scsi_eh_wakeup(struct Scsi_Host *shost)
@@ -102,6 +104,116 @@ static int scsi_host_eh_past_deadline(struct Scsi_Host *shost)
}
/**
+ * scmd_eh_abort_handler - Handle command aborts
+ * @work: command to be aborted.
+ */
+void
+scmd_eh_abort_handler(struct work_struct *work)
+{
+ struct scsi_cmnd *scmd =
+ container_of(work, struct scsi_cmnd, abort_work.work);
+ struct scsi_device *sdev = scmd->device;
+ unsigned long flags;
+ int rtn;
+
+ spin_lock_irqsave(sdev->host->host_lock, flags);
+ if (scsi_host_eh_past_deadline(sdev->host)) {
+ spin_unlock_irqrestore(sdev->host->host_lock, flags);
+ SCSI_LOG_ERROR_RECOVERY(3,
+ scmd_printk(KERN_INFO, scmd,
+ "scmd %p eh timeout, not aborting\n",
+ scmd));
+ } else {
+ spin_unlock_irqrestore(sdev->host->host_lock, flags);
+ SCSI_LOG_ERROR_RECOVERY(3,
+ scmd_printk(KERN_INFO, scmd,
+ "aborting command %p\n", scmd));
+ rtn = scsi_try_to_abort_cmd(sdev->host->hostt, scmd);
+ if (rtn == SUCCESS) {
+ scmd->result |= DID_TIME_OUT << 16;
+ if (!scsi_noretry_cmd(scmd) &&
+ (++scmd->retries <= scmd->allowed)) {
+ SCSI_LOG_ERROR_RECOVERY(3,
+ scmd_printk(KERN_WARNING, scmd,
+ "scmd %p retry "
+ "aborted command\n", scmd));
+ scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
+ } else {
+ SCSI_LOG_ERROR_RECOVERY(3,
+ scmd_printk(KERN_WARNING, scmd,
+ "scmd %p finish "
+ "aborted command\n", scmd));
+ scsi_finish_command(scmd);
+ }
+ return;
+ }
+ SCSI_LOG_ERROR_RECOVERY(3,
+ scmd_printk(KERN_INFO, scmd,
+ "scmd %p abort failed, rtn %d\n",
+ scmd, rtn));
+ }
+
+ if (!scsi_eh_scmd_add(scmd, 0)) {
+ SCSI_LOG_ERROR_RECOVERY(3,
+ scmd_printk(KERN_WARNING, scmd,
+ "scmd %p terminate "
+ "aborted command\n", scmd));
+ scmd->result |= DID_TIME_OUT << 16;
+ scsi_finish_command(scmd);
+ }
+}
+
+/**
+ * scsi_abort_command - schedule a command abort
+ * @scmd: scmd to abort.
+ *
+ * We only need to abort commands after a command timeout
+ */
+static int
+scsi_abort_command(struct scsi_cmnd *scmd)
+{
+ struct scsi_device *sdev = scmd->device;
+ struct Scsi_Host *shost = sdev->host;
+ unsigned long flags;
+
+ if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
+ /*
+ * Retry after abort failed, escalate to next level.
+ */
+ SCSI_LOG_ERROR_RECOVERY(3,
+ scmd_printk(KERN_INFO, scmd,
+ "scmd %p previous abort failed\n", scmd));
+ cancel_delayed_work(&scmd->abort_work);
+ return FAILED;
+ }
+
+ /*
+ * Do not try a command abort if
+ * SCSI EH has already started.
+ */
+ spin_lock_irqsave(shost->host_lock, flags);
+ if (scsi_host_in_recovery(shost)) {
+ spin_unlock_irqrestore(shost->host_lock, flags);
+ SCSI_LOG_ERROR_RECOVERY(3,
+ scmd_printk(KERN_INFO, scmd,
+ "scmd %p not aborting, host in recovery\n",
+ scmd));
+ return FAILED;
+ }
+
+ if (shost->eh_deadline && !shost->last_reset)
+ shost->last_reset = jiffies;
+ spin_unlock_irqrestore(shost->host_lock, flags);
+
+ scmd->eh_eflags |= SCSI_EH_ABORT_SCHEDULED;
+ SCSI_LOG_ERROR_RECOVERY(3,
+ scmd_printk(KERN_INFO, scmd,
+ "scmd %p abort scheduled\n", scmd));
+ queue_delayed_work(shost->tmf_work_q, &scmd->abort_work, HZ / 100);
+ return SUCCESS;
+}
+
+/**
* scsi_eh_scmd_add - add scsi cmd to error handling.
* @scmd: scmd to run eh on.
* @eh_flag: optional SCSI_EH flag.
@@ -127,6 +239,8 @@ int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
shost->last_reset = jiffies;
ret = 1;
+ if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED)
+ eh_flag &= ~SCSI_EH_CANCEL_CMD;
scmd->eh_eflags |= eh_flag;
list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
shost->host_failed++;
@@ -163,6 +277,10 @@ enum blk_eh_timer_return scsi_times_out(struct request *req)
else if (host->hostt->eh_timed_out)
rtn = host->hostt->eh_timed_out(scmd);
+ if (rtn == BLK_EH_NOT_HANDLED && !host->hostt->no_async_abort)
+ if (scsi_abort_command(scmd) == SUCCESS)
+ return BLK_EH_NOT_HANDLED;
+
scmd->result |= DID_TIME_OUT << 16;
if (unlikely(rtn == BLK_EH_NOT_HANDLED &&
@@ -1514,7 +1632,7 @@ static void scsi_eh_offline_sdevs(struct list_head *work_q,
}
/**
- * scsi_noretry_cmd - determinte if command should be failed fast
+ * scsi_noretry_cmd - determine if command should be failed fast
* @scmd: SCSI cmd to examine.
*/
int scsi_noretry_cmd(struct scsi_cmnd *scmd)
@@ -1522,6 +1640,8 @@ int scsi_noretry_cmd(struct scsi_cmnd *scmd)
switch (host_byte(scmd->result)) {
case DID_OK:
break;
+ case DID_TIME_OUT:
+ goto check_type;
case DID_BUS_BUSY:
return (scmd->request->cmd_flags & REQ_FAILFAST_TRANSPORT);
case DID_PARITY:
@@ -1535,18 +1655,19 @@ int scsi_noretry_cmd(struct scsi_cmnd *scmd)
return (scmd->request->cmd_flags & REQ_FAILFAST_DRIVER);
}
- switch (status_byte(scmd->result)) {
- case CHECK_CONDITION:
- /*
- * assume caller has checked sense and determinted
- * the check condition was retryable.
- */
- if (scmd->request->cmd_flags & REQ_FAILFAST_DEV ||
- scmd->request->cmd_type == REQ_TYPE_BLOCK_PC)
- return 1;
- }
+ if (status_byte(scmd->result) != CHECK_CONDITION)
+ return 0;
- return 0;
+check_type:
+ /*
+ * assume caller has checked sense and determined
+ * the check condition was retryable.
+ */
+ if (scmd->request->cmd_flags & REQ_FAILFAST_DEV ||
+ scmd->request->cmd_type == REQ_TYPE_BLOCK_PC)
+ return 1;
+ else
+ return 0;
}
/**
@@ -1596,9 +1717,13 @@ int scsi_decide_disposition(struct scsi_cmnd *scmd)
* looks good. drop through, and check the next byte.
*/
break;
+ case DID_ABORT:
+ if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
+ scmd->result |= DID_TIME_OUT << 16;
+ return SUCCESS;
+ }
case DID_NO_CONNECT:
case DID_BAD_TARGET:
- case DID_ABORT:
/*
* note - this means that we just report the status back
* to the top level driver, not that we actually think
diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h
index 8f9a0cadc296..f079a598bed4 100644
--- a/drivers/scsi/scsi_priv.h
+++ b/drivers/scsi/scsi_priv.h
@@ -19,6 +19,7 @@ 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) \
(((scmd)->sense_buffer[0] & 0x70) == 0x70)
@@ -66,6 +67,7 @@ extern int __init scsi_init_devinfo(void);
extern void scsi_exit_devinfo(void);
/* scsi_error.c */
+extern void scmd_eh_abort_handler(struct work_struct *work);
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);
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index de5f5d8f1f8a..91558a1f97f4 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -55,6 +55,7 @@ struct scsi_cmnd {
struct scsi_device *device;
struct list_head list; /* scsi_cmnd participates in queue lists */
struct list_head eh_entry; /* entry for the host eh_cmd_q */
+ struct delayed_work abort_work;
int eh_eflags; /* Used by error handlr */
/*
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 653630ef3884..392e5996266a 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -479,6 +479,11 @@ struct scsi_host_template {
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.
*/
unsigned int max_host_blocked;
@@ -689,6 +694,11 @@ struct Scsi_Host {
struct workqueue_struct *work_q;
/*
+ * Task management function work queue
+ */
+ struct workqueue_struct *tmf_work_q;
+
+ /*
* Host has rejected a command because it was busy.
*/
unsigned int host_blocked;