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Commit 8e8c9d01 authored by Hannes Reinecke's avatar Hannes Reinecke Committed by Martin K. Petersen
Browse files

scsi: make eh_eflags persistent 



If a failed command is retried and fails again we need
to enter SCSI EH, otherwise we will never be able to
recover the command.
To detect this situation we must not clear scmd->eh_eflags
when EH finishes but rather make it persistent throughout
the lifetime of the command.

Signed-off-by: default avatarHannes Reinecke <hare@suse.de>
Reviewed-by: default avatarBenjamin Block <bblock@linux.vnet.ibm.com>
Reviewed-by: default avatarBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: default avatarJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 90965761

Documentation/scsi/scsi_eh.txt

+7 −7
Original line number Diff line number Diff line
@@ -105,11 +105,14 @@ function 


 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. If that fails

    Step #3 is taken.

    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),

    or when the EH deadline is expired. In these case Step #3 is taken.



 2. scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD) is invoked for the

    command.  See [1-3] for more information.

 3. scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD) is invoked for the

    command.  See [1-4] for more information.



[1-3] Asynchronous command aborts
@@ -263,7 +266,6 @@ scmd->allowed. 


 3. scmd recovered

    ACTION: scsi_eh_finish_cmd() is invoked to EH-finish scmd

	- clear scmd->eh_eflags

	- scsi_setup_cmd_retry()

	- move from local eh_work_q to local eh_done_q

    LOCKING: none
@@ -456,8 +458,6 @@ except for #1 must be implemented by eh_strategy_handler(). 


 - shost->host_failed is zero.



 - Each scmd's eh_eflags field is cleared.



 - Each scmd is in such a state that scsi_setup_cmd_retry() on the

   scmd doesn't make any difference.

drivers/scsi/libsas/sas_scsi_host.c

+0 −2
Original line number Diff line number Diff line
@@ -613,8 +613,6 @@ static void sas_eh_handle_sas_errors(struct Scsi_Host *shost, struct list_head * 
		SAS_DPRINTK("trying to find task 0x%p\n", task);

		res = sas_scsi_find_task(task);



		cmd->eh_eflags = 0;



		switch (res) {

		case TASK_IS_DONE:

			SAS_DPRINTK("%s: task 0x%p is done\n", __func__,

drivers/scsi/scsi_error.c

+2 −2
Original line number Diff line number Diff line
@@ -188,7 +188,6 @@ scsi_abort_command(struct scsi_cmnd *scmd) 
		/*

		 * Retry after abort failed, escalate to next level.

		 */

		scmd->eh_eflags &= ~SCSI_EH_ABORT_SCHEDULED;

		SCSI_LOG_ERROR_RECOVERY(3,

			scmd_printk(KERN_INFO, scmd,

				    "previous abort failed\n"));
@@ -937,6 +936,7 @@ void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses, 
	ses->result = scmd->result;

	ses->underflow = scmd->underflow;

	ses->prot_op = scmd->prot_op;

	ses->eh_eflags = scmd->eh_eflags;



	scmd->prot_op = SCSI_PROT_NORMAL;

	scmd->eh_eflags = 0;
@@ -1000,6 +1000,7 @@ void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses) 
	scmd->result = ses->result;

	scmd->underflow = ses->underflow;

	scmd->prot_op = ses->prot_op;

	scmd->eh_eflags = ses->eh_eflags;

}

EXPORT_SYMBOL(scsi_eh_restore_cmnd);
@@ -1132,7 +1133,6 @@ static int scsi_eh_action(struct scsi_cmnd *scmd, int rtn) 
 */

void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)

{

	scmd->eh_eflags = 0;

	list_move_tail(&scmd->eh_entry, done_q);

}

EXPORT_SYMBOL(scsi_eh_finish_cmd);

include/scsi/scsi_eh.h

+1 −0
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ extern int scsi_ioctl_reset(struct scsi_device *, int __user *); 
struct scsi_eh_save {

	/* saved state */

	int result;

	int eh_eflags;

	enum dma_data_direction data_direction;

	unsigned underflow;

	unsigned char cmd_len;