Commit 2a242d59 authored by Mike Christie's avatar Mike Christie Committed by Martin K. Petersen
Browse files

scsi: core: Add limitless cmd retry support 

Add infinite retry support to SCSI midlayer by combining common checks for
retries into some helper functions, and then checking for the
-1/SCSI_CMD_RETRIES_NO_LIMIT.

Link: https://lore.kernel.org/r/1601566554-26752-2-git-send-email-michael.christie@oracle.com


Reviewed-by: default avatarBart Van Assche <bvanassche@acm.org>
Signed-off-by: default avatarMike Christie <michael.christie@oracle.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 7010645b

drivers/scsi/scsi_error.c

+23 −10
Original line number Diff line number Diff line
@@ -116,6 +116,14 @@ static int scsi_host_eh_past_deadline(struct Scsi_Host *shost) 
	return 1;

}



static bool scsi_cmd_retry_allowed(struct scsi_cmnd *cmd)

{

	if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)

		return true;



	return ++cmd->retries <= cmd->allowed;

}



/**

 * scmd_eh_abort_handler - Handle command aborts

 * @work:	command to be aborted.
@@ -151,7 +159,7 @@ scmd_eh_abort_handler(struct work_struct *work) 
						    "eh timeout, not retrying "

						    "aborted command\n"));

			} else if (!scsi_noretry_cmd(scmd) &&

			    (++scmd->retries <= scmd->allowed)) {

				   scsi_cmd_retry_allowed(scmd)) {

				SCSI_LOG_ERROR_RECOVERY(3,

					scmd_printk(KERN_WARNING, scmd,

						    "retry aborted command\n"));
@@ -1264,10 +1272,17 @@ int scsi_eh_get_sense(struct list_head *work_q, 
		 * upper level.

		 */

		if (rtn == SUCCESS)

			/* we don't want this command reissued, just

			 * finished with the sense data, so set

			 * retries to the max allowed to ensure it

			 * won't get reissued */

			/*

			 * We don't want this command reissued, just finished

			 * with the sense data, so set retries to the max

			 * allowed to ensure it won't get reissued. If the user

			 * has requested infinite retries, we also want to

			 * finish this command, so force completion by setting

			 * retries and allowed to the same value.

			 */

			if (scmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)

				scmd->retries = scmd->allowed = 1;

			else

				scmd->retries = scmd->allowed;

		else if (rtn != NEEDS_RETRY)

			continue;
@@ -1944,8 +1959,7 @@ maybe_retry: 
	 * the request was not marked fast fail.  Note that above,

	 * even if the request is marked fast fail, we still requeue

	 * for queue congestion conditions (QUEUE_FULL or BUSY) */

	if ((++scmd->retries) <= scmd->allowed

	    && !scsi_noretry_cmd(scmd)) {

	if (scsi_cmd_retry_allowed(scmd) && !scsi_noretry_cmd(scmd)) {

		return NEEDS_RETRY;

	} else {

		/*
@@ -2091,8 +2105,7 @@ void scsi_eh_flush_done_q(struct list_head *done_q) 
	list_for_each_entry_safe(scmd, next, done_q, eh_entry) {

		list_del_init(&scmd->eh_entry);

		if (scsi_device_online(scmd->device) &&

		    !scsi_noretry_cmd(scmd) &&

		    (++scmd->retries <= scmd->allowed)) {

		    !scsi_noretry_cmd(scmd) && scsi_cmd_retry_allowed(scmd)) {

			SCSI_LOG_ERROR_RECOVERY(3,

				scmd_printk(KERN_INFO, scmd,

					     "%s: flush retry cmd\n",

drivers/scsi/scsi_lib.c

+19 −10
Original line number Diff line number Diff line
@@ -669,6 +669,23 @@ static void scsi_io_completion_reprep(struct scsi_cmnd *cmd, 
	scsi_mq_requeue_cmd(cmd);

}



static bool scsi_cmd_runtime_exceeced(struct scsi_cmnd *cmd)

{

	struct request *req = cmd->request;

	unsigned long wait_for;



	if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)

		return false;



	wait_for = (cmd->allowed + 1) * req->timeout;

	if (time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {

		scmd_printk(KERN_ERR, cmd, "timing out command, waited %lus\n",

			    wait_for/HZ);

		return true;

	}

	return false;

}



/* Helper for scsi_io_completion() when special action required. */

static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result)

{
@@ -677,7 +694,6 @@ static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result) 
	int level = 0;

	enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,

	      ACTION_DELAYED_RETRY} action;

	unsigned long wait_for = (cmd->allowed + 1) * req->timeout;

	struct scsi_sense_hdr sshdr;

	bool sense_valid;

	bool sense_current = true;      /* false implies "deferred sense" */
@@ -782,8 +798,7 @@ static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result) 
	} else

		action = ACTION_FAIL;



	if (action != ACTION_FAIL &&

	    time_before(cmd->jiffies_at_alloc + wait_for, jiffies))

	if (action != ACTION_FAIL && scsi_cmd_runtime_exceeced(cmd))

		action = ACTION_FAIL;



	switch (action) {
@@ -1456,7 +1471,6 @@ static bool scsi_mq_lld_busy(struct request_queue *q) 
static void scsi_softirq_done(struct request *rq)

{

	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);

	unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;

	int disposition;



	INIT_LIST_HEAD(&cmd->eh_entry);
@@ -1466,13 +1480,8 @@ static void scsi_softirq_done(struct request *rq) 
		atomic_inc(&cmd->device->ioerr_cnt);



	disposition = scsi_decide_disposition(cmd);

	if (disposition != SUCCESS &&

	    time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {

		scmd_printk(KERN_ERR, cmd,

			    "timing out command, waited %lus\n",

			    wait_for/HZ);

	if (disposition != SUCCESS && scsi_cmd_runtime_exceeced(cmd))

		disposition = SUCCESS;

	}



	scsi_log_completion(cmd, disposition);

drivers/scsi/scsi_priv.h

+1 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ struct scsi_host_template; 
struct Scsi_Host;

struct scsi_nl_hdr;



#define SCSI_CMD_RETRIES_NO_LIMIT -1



/*

 * Scsi Error Handler Flags

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