Since sas_ata does not implement ->freeze(), completions for scmds and
internal commands can still arrive concurrent with
ata_scsi_cmd_error_handler() and sas_ata_post_internal() respectively.
By the time either of those is called libata has committed to completing
the qc, and the ATA_PFLAG_FROZEN flag tells sas_ata_task_done() it has
lost the race.
In the sas_ata_post_internal() case we take on the additional
responsibility of freeing the sas_task to close the race with
sas_ata_task_done() freeing the the task while sas_ata_post_internal()
is in the process of invoking ->lldd_abort_task().
Cc: Darrick J. Wong <djwong@xxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
drivers/scsi/libsas/sas_ata.c | 85 +++++++++++++++++++++++++++++++----
drivers/scsi/libsas/sas_scsi_host.c | 44 ------------------
include/scsi/libsas.h | 1
3 files changed, 76 insertions(+), 54 deletions(-)
diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
index 649b04b..c989d7f 100644
--- a/drivers/scsi/libsas/sas_ata.c
+++ b/drivers/scsi/libsas/sas_ata.c
@@ -100,15 +100,31 @@ static void sas_ata_task_done(struct sas_task *task)
enum ata_completion_errors ac;
unsigned long flags;
struct ata_link *link;
+ struct ata_port *ap;
if (!qc)
goto qc_already_gone;
- dev = qc->ap->private_data;
+ ap = qc->ap;
+ dev = ap->private_data;
sas_ha = dev->port->ha;
- link = &dev->sata_dev.ap->link;
+ link = &ap->link;
+
+ spin_lock_irqsave(ap->lock, flags);
+ /* check if we lost the race with libata/sas_ata_post_internal() */
+ if (unlikely(ap->pflags & ATA_PFLAG_FROZEN)) {
+ spin_unlock_irqrestore(ap->lock, flags);
+ if (qc->scsicmd)
+ goto qc_already_gone;
+ else {
+ /* if eh is not involved and the port is frozen then the
+ * ata internal abort process has taken responsibility
+ * for this sas_task
+ */
+ return;
+ }
+ }
- spin_lock_irqsave(dev->sata_dev.ap->lock, flags);
if (stat->stat == SAS_PROTO_RESPONSE || stat->stat == SAM_STAT_GOOD ||
((stat->stat == SAM_STAT_CHECK_CONDITION &&
dev->sata_dev.command_set == ATAPI_COMMAND_SET))) {
@@ -143,7 +159,7 @@ static void sas_ata_task_done(struct sas_task *task)
if (qc->scsicmd)
ASSIGN_SAS_TASK(qc->scsicmd, NULL);
ata_qc_complete(qc);
- spin_unlock_irqrestore(dev->sata_dev.ap->lock, flags);
+ spin_unlock_irqrestore(ap->lock, flags);
qc_already_gone:
list_del_init(&task->list);
@@ -320,6 +336,55 @@ static int sas_ata_soft_reset(struct ata_link *link, unsigned int *class,
return ret;
}
+/*
+ * notify the lldd to forget the sas_task for this internal ata command
+ * that bypasses scsi-eh
+ */
+static void sas_ata_internal_abort(struct sas_task *task)
+{
+ struct sas_internal *si =
+ to_sas_internal(task->dev->port->ha->core.shost->transportt);
+ unsigned long flags;
+ int res;
+
+ spin_lock_irqsave(&task->task_state_lock, flags);
+ if (task->task_state_flags & SAS_TASK_STATE_ABORTED ||
+ task->task_state_flags & SAS_TASK_STATE_DONE) {
+ spin_unlock_irqrestore(&task->task_state_lock, flags);
+ SAS_DPRINTK("%s: Task %p already finished.\n", __func__,
+ task);
+ goto out;
+ }
+ task->task_state_flags |= SAS_TASK_STATE_ABORTED;
+ spin_unlock_irqrestore(&task->task_state_lock, flags);
+
+ res = si->dft->lldd_abort_task(task);
+
+ spin_lock_irqsave(&task->task_state_lock, flags);
+ if ((task->task_state_flags & SAS_TASK_STATE_DONE) ||
+ (res == TMF_RESP_FUNC_COMPLETE))
+ {
+ spin_unlock_irqrestore(&task->task_state_lock, flags);
+ goto out;
+ }
+
+ /* XXX we are not prepared to deal with ->lldd_abort_task()
+ * failures. TODO: lldds need to unconditionally forget about
+ * aborted ata tasks, otherwise we (likely) leak the sas task
+ * here
+ */
+ SAS_DPRINTK("%s: Task %p leaked.\n", __func__, task);
+
+ if (!(task->task_state_flags & SAS_TASK_STATE_DONE))
+ task->task_state_flags &= ~SAS_TASK_STATE_ABORTED;
+ spin_unlock_irqrestore(&task->task_state_lock, flags);
+
+ return;
+ out:
+ list_del_init(&task->list);
+ sas_free_task(task);
+}
+
static void sas_ata_post_internal(struct ata_queued_cmd *qc)
{
if (qc->flags & ATA_QCFLAG_FAILED)
@@ -327,10 +392,12 @@ static void sas_ata_post_internal(struct ata_queued_cmd *qc)
if (qc->err_mask) {
/*
- * Find the sas_task and kill it. By this point,
- * libata has decided to kill the qc, so we needn't
- * bother with sas_ata_task_done. But we still
- * ought to abort the task.
+ * Find the sas_task and kill it. By this point, libata
+ * has decided to kill the qc and has frozen the port.
+ * In this state sas_ata_task_done() will no longer free
+ * the sas_task, so we need to notify the lldd (via
+ * ->lldd_abort_task) that the task is dead and free it
+ * ourselves.
*/
struct sas_task *task = qc->lldd_task;
unsigned long flags;
@@ -343,7 +410,7 @@ static void sas_ata_post_internal(struct ata_queued_cmd *qc)
spin_unlock_irqrestore(&task->task_state_lock, flags);
task->uldd_task = NULL;
- __sas_task_abort(task);
+ sas_ata_internal_abort(task);
}
}
}
diff --git a/drivers/scsi/libsas/sas_scsi_host.c b/drivers/scsi/libsas/sas_scsi_host.c
index 8c91afa..f32c628 100644
--- a/drivers/scsi/libsas/sas_scsi_host.c
+++ b/drivers/scsi/libsas/sas_scsi_host.c
@@ -963,49 +963,6 @@ void sas_shutdown_queue(struct sas_ha_struct *sas_ha)
}
/*
- * Call the LLDD task abort routine directly. This function is intended for
- * use by upper layers that need to tell the LLDD to abort a task.
- */
-int __sas_task_abort(struct sas_task *task)
-{
- struct sas_internal *si =
- to_sas_internal(task->dev->port->ha->core.shost->transportt);
- unsigned long flags;
- int res;
-
- spin_lock_irqsave(&task->task_state_lock, flags);
- if (task->task_state_flags & SAS_TASK_STATE_ABORTED ||
- task->task_state_flags & SAS_TASK_STATE_DONE) {
- spin_unlock_irqrestore(&task->task_state_lock, flags);
- SAS_DPRINTK("%s: Task %p already finished.\n", __func__,
- task);
- return 0;
- }
- task->task_state_flags |= SAS_TASK_STATE_ABORTED;
- spin_unlock_irqrestore(&task->task_state_lock, flags);
-
- if (!si->dft->lldd_abort_task)
- return -ENODEV;
-
- res = si->dft->lldd_abort_task(task);
-
- spin_lock_irqsave(&task->task_state_lock, flags);
- if ((task->task_state_flags & SAS_TASK_STATE_DONE) ||
- (res == TMF_RESP_FUNC_COMPLETE))
- {
- spin_unlock_irqrestore(&task->task_state_lock, flags);
- task->task_done(task);
- return 0;
- }
-
- if (!(task->task_state_flags & SAS_TASK_STATE_DONE))
- task->task_state_flags &= ~SAS_TASK_STATE_ABORTED;
- spin_unlock_irqrestore(&task->task_state_lock, flags);
-
- return -EAGAIN;
-}
-
-/*
* Tell an upper layer that it needs to initiate an abort for a given task.
* This should only ever be called by an LLDD.
*/
@@ -1103,7 +1060,6 @@ EXPORT_SYMBOL_GPL(sas_slave_configure);
EXPORT_SYMBOL_GPL(sas_change_queue_depth);
EXPORT_SYMBOL_GPL(sas_change_queue_type);
EXPORT_SYMBOL_GPL(sas_bios_param);
-EXPORT_SYMBOL_GPL(__sas_task_abort);
EXPORT_SYMBOL_GPL(sas_task_abort);
EXPORT_SYMBOL_GPL(sas_phy_reset);
EXPORT_SYMBOL_GPL(sas_phy_enable);
diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
index 2ff089b..6064f82 100644
--- a/include/scsi/libsas.h
+++ b/include/scsi/libsas.h
@@ -653,7 +653,6 @@ void sas_unregister_dev(struct asd_sas_port *port, struct domain_device *);
void sas_init_dev(struct domain_device *);
void sas_task_abort(struct sas_task *);
-int __sas_task_abort(struct sas_task *);
int sas_eh_device_reset_handler(struct scsi_cmnd *cmd);
int sas_eh_bus_reset_handler(struct scsi_cmnd *cmd);
--
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