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.
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
Cc: Ren Mingxin <renmx@xxxxxxxxxxxxxx>
---
drivers/scsi/scsi.c | 3 +
drivers/scsi/scsi_error.c | 149 ++++++++++++++++++++++++++++++++++++++++++----
drivers/scsi/scsi_priv.h | 2 +
include/scsi/scsi_cmnd.h | 1 +
include/scsi/scsi_host.h | 5 ++
5 files changed, 147 insertions(+), 13 deletions(-)
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index fe0bcb1..2b04a57 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);
@@ -353,6 +354,8 @@ 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 c88cb7e..8eaf524 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -53,6 +53,7 @@ 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)
@@ -100,6 +101,115 @@ 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) {
+ /*
+ * command abort timed out.
+ */
+ SCSI_LOG_ERROR_RECOVERY(3,
+ scmd_printk(KERN_INFO, scmd,
+ "scmd %p abort timeout\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));
+ schedule_delayed_work(&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.
@@ -125,6 +235,8 @@ 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++;
@@ -161,6 +273,10 @@ 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 &&
@@ -1577,7 +1693,7 @@ 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)
@@ -1585,6 +1701,8 @@ 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:
@@ -1598,18 +1716,19 @@ 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;
- }
+ switch (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;
}
/**
@@ -1659,9 +1778,13 @@ 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 8f9a0ca..f079a59 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 de5f5d8..91558a1 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 896bb05..6ca9174 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -476,6 +476,11 @@ struct scsi_host_template {
unsigned ordered_tag: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;
--
1.7.12.4
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
