[SCSI] libsas: remove ata_port.lock management duties from lldds
Each libsas driver (mvsas, pm8001, and isci) has invented a different
method for managing the ap->lock. The lock is held by the ata
->queuecommand() path. mvsas drops it prior to acquiring any internal
locks which allows it to hold its internal lock across calls to
task->task_done(). This capability is important as it is the only way
the driver can flush task->task_done() instances to guarantee that it no
longer has any in-flight references to a domain_device at
->lldd_dev_gone() time.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
index 83118d0..81ce39d 100644
--- a/drivers/scsi/libsas/sas_ata.c
+++ b/drivers/scsi/libsas/sas_ata.c
@@ -166,23 +166,30 @@
static unsigned int sas_ata_qc_issue(struct ata_queued_cmd *qc)
{
- int res;
+ unsigned long flags;
struct sas_task *task;
- struct domain_device *dev = qc->ap->private_data;
+ struct scatterlist *sg;
+ int ret = AC_ERR_SYSTEM;
+ unsigned int si, xfer = 0;
+ struct ata_port *ap = qc->ap;
+ struct domain_device *dev = ap->private_data;
struct sas_ha_struct *sas_ha = dev->port->ha;
struct Scsi_Host *host = sas_ha->core.shost;
struct sas_internal *i = to_sas_internal(host->transportt);
- struct scatterlist *sg;
- unsigned int xfer = 0;
- unsigned int si;
+
+ /* TODO: audit callers to ensure they are ready for qc_issue to
+ * unconditionally re-enable interrupts
+ */
+ local_irq_save(flags);
+ spin_unlock(ap->lock);
/* If the device fell off, no sense in issuing commands */
if (dev->gone)
- return AC_ERR_SYSTEM;
+ goto out;
task = sas_alloc_task(GFP_ATOMIC);
if (!task)
- return AC_ERR_SYSTEM;
+ goto out;
task->dev = dev;
task->task_proto = SAS_PROTOCOL_STP;
task->task_done = sas_ata_task_done;
@@ -227,21 +234,24 @@
ASSIGN_SAS_TASK(qc->scsicmd, task);
if (sas_ha->lldd_max_execute_num < 2)
- res = i->dft->lldd_execute_task(task, 1, GFP_ATOMIC);
+ ret = i->dft->lldd_execute_task(task, 1, GFP_ATOMIC);
else
- res = sas_queue_up(task);
+ ret = sas_queue_up(task);
/* Examine */
- if (res) {
- SAS_DPRINTK("lldd_execute_task returned: %d\n", res);
+ if (ret) {
+ SAS_DPRINTK("lldd_execute_task returned: %d\n", ret);
if (qc->scsicmd)
ASSIGN_SAS_TASK(qc->scsicmd, NULL);
sas_free_task(task);
- return AC_ERR_SYSTEM;
+ ret = AC_ERR_SYSTEM;
}
- return 0;
+ out:
+ spin_lock(ap->lock);
+ local_irq_restore(flags);
+ return ret;
}
static bool sas_ata_qc_fill_rtf(struct ata_queued_cmd *qc)