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Commit a3a14252 authored by Dan Williams's avatar Dan Williams Committed by James Bottomley
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[SCSI] libsas: prevent double completion of scmds from eh 



We invoke task->task_done() to free the task in the eh case, but at this
point we are prepared for scsi_eh_flush_done_q() to finish off the scmd.

Introduce sas_end_task() to capture the final response status from the
lldd and free the task.

Also take the opportunity to kill this warning.
drivers/scsi/libsas/sas_scsi_host.c: In function ‘sas_end_task’:
drivers/scsi/libsas/sas_scsi_host.c:102:3: warning: case value ‘2’ not in enumerated type ‘enum exec_status’ [-Wswitch]

Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent 3dff5721

drivers/scsi/libsas/sas_scsi_host.c

+33 −28
Original line number Diff line number Diff line
@@ -49,27 +49,12 @@ 
#include <linux/scatterlist.h>

#include <linux/libata.h>



/* ---------- SCSI Host glue ---------- */



static void sas_scsi_task_done(struct sas_task *task)

/* record final status and free the task */

static void sas_end_task(struct scsi_cmnd *sc, struct sas_task *task)

{

	struct task_status_struct *ts = &task->task_status;

	struct scsi_cmnd *sc = task->uldd_task;

	int hs = 0, stat = 0;



	if (unlikely(task->task_state_flags & SAS_TASK_STATE_ABORTED)) {

		/* Aborted tasks will be completed by the error handler */

		SAS_DPRINTK("task done but aborted\n");

		return;

	}



	if (unlikely(!sc)) {

		SAS_DPRINTK("task_done called with non existing SCSI cmnd!\n");

		list_del_init(&task->list);

		sas_free_task(task);

		return;

	}



	if (ts->resp == SAS_TASK_UNDELIVERED) {

		/* transport error */

		hs = DID_NO_CONNECT;
@@ -124,10 +109,32 @@ static void sas_scsi_task_done(struct sas_task *task) 
			break;

		}

	}

	ASSIGN_SAS_TASK(sc, NULL);



	sc->result = (hs << 16) | stat;

	ASSIGN_SAS_TASK(sc, NULL);

	list_del_init(&task->list);

	sas_free_task(task);

}



static void sas_scsi_task_done(struct sas_task *task)

{

	struct scsi_cmnd *sc = task->uldd_task;



	if (unlikely(task->task_state_flags & SAS_TASK_STATE_ABORTED)) {

		/* Aborted tasks will be completed by the error handler */

		SAS_DPRINTK("task done but aborted\n");

		return;

	}



	if (unlikely(!sc)) {

		SAS_DPRINTK("task_done called with non existing SCSI cmnd!\n");

		list_del_init(&task->list);

		sas_free_task(task);

		return;

	}



	ASSIGN_SAS_TASK(sc, NULL);

	sas_end_task(sc, task);

	sc->scsi_done(sc);

}
@@ -236,18 +243,16 @@ static void sas_eh_finish_cmd(struct scsi_cmnd *cmd) 
	struct sas_task *task = TO_SAS_TASK(cmd);

	struct sas_ha_struct *sas_ha = SHOST_TO_SAS_HA(cmd->device->host);



	/* remove the aborted task flag to allow the task to be

	 * completed now. At this point, we only get called following

	 * an actual abort of the task, so we should be guaranteed not

	 * to be racing with any completions from the LLD (hence we

	 * don't need the task state lock to clear the flag) */

	task->task_state_flags &= ~SAS_TASK_STATE_ABORTED;

	/* Now call task_done.  However, task will be free'd after

	 * this */

	task->task_done(task);

	/* At this point, we only get called following an actual abort

	 * of the task, so we should be guaranteed not to be racing with

	 * any completions from the LLD.  Task is freed after this.

	 */

	sas_end_task(cmd, task);



	/* now finish the command and move it on to the error

	 * handler done list, this also takes it off the

	 * error handler pending list */

	 * error handler pending list.

	 */

	scsi_eh_finish_cmd(cmd, &sas_ha->eh_done_q);

}

include/scsi/libsas.h

+4 −1
Original line number Diff line number Diff line
@@ -452,7 +452,10 @@ enum service_response { 
};



enum exec_status {

	/* The SAM_STAT_.. codes fit in the lower 6 bits */

	/* The SAM_STAT_.. codes fit in the lower 6 bits, alias some of

	 * them here to silence 'case value not in enumerated type' warnings

	 */

	__SAM_STAT_CHECK_CONDITION = SAM_STAT_CHECK_CONDITION,



	SAS_DEV_NO_RESPONSE = 0x80,

	SAS_DATA_UNDERRUN,