New EH may issue internal commands to recover from error while failed
qc's are still hanging around. To allow such usage, reserve tag
ATA_MAX_QUEUE-1 for internal command. This also makes it easy to tell
whether a qc is for internal command or not. ata_tag_internal() test
implements this test.
To avoid breaking existing drivers, ata_exec_internal() uses
ATA_TAG_INTERNAL only for drivers which implement ->error_handler.
For drivers on old EH, tag 0 is used as before. Note that this makes
ata_tag_internal() test valid only when ->error_handler is
implemented. This is okay as drivers on old EH should not and does
not have any reason to use ata_tag_internal().
Signed-off-by: Tejun Heo <htejun@xxxxxxxxx>
---
drivers/scsi/libata-core.c | 33 +++++++++++++++++++++++++++++----
include/linux/libata.h | 9 ++++++++-
2 files changed, 37 insertions(+), 5 deletions(-)
42932fc5ad9150819871b9fa01cae6dceaf6886c
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 7907f9a..7a7297d 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -978,22 +978,45 @@ void ata_qc_complete_internal(struct ata
* LOCKING:
* None. Should be called with kernel context, might sleep.
*/
-
unsigned ata_exec_internal(struct ata_port *ap, struct ata_device *dev,
struct ata_taskfile *tf, const u8 *cdb,
int dma_dir, void *buf, unsigned int buflen)
{
u8 command = tf->command;
struct ata_queued_cmd *qc;
+ unsigned int tag, preempted_tag;
DECLARE_COMPLETION(wait);
unsigned long flags;
unsigned int err_mask;
spin_lock_irqsave(&ap->host_set->lock, flags);
- qc = ata_qc_new_init(ap, dev);
- BUG_ON(qc == NULL);
+ /* initialize internal qc */
+
+ /* XXX: Tag 0 is used for drivers with legacy EH as some
+ * drivers choke if any other tag is given. This breaks
+ * ata_tag_internal() test for those drivers. Don't use new
+ * EH stuff without converting to it.
+ */
+ if (ap->ops->error_handler)
+ tag = ATA_TAG_INTERNAL;
+ else
+ tag = 0;
+
+ if (test_and_set_bit(tag, &ap->qactive))
+ BUG();
+ qc = ata_qc_from_tag(ap, tag);
+
+ qc->tag = tag;
+ qc->scsicmd = NULL;
+ qc->ap = ap;
+ qc->dev = dev;
+ ata_qc_reinit(qc);
+
+ preempted_tag = ap->active_tag;
+ ap->active_tag = ATA_TAG_POISON;
+ /* prepare & issue qc */
qc->tf = *tf;
if (cdb)
memcpy(qc->cdb, cdb, ATAPI_CDB_LEN);
@@ -1037,6 +1060,7 @@ unsigned ata_exec_internal(struct ata_po
err_mask = qc->err_mask;
ata_qc_free(qc);
+ ap->active_tag = preempted_tag;
/* XXX - Some LLDDs (sata_mv) disable port on command failure.
* Until those drivers are fixed, we detect the condition
@@ -4032,7 +4056,8 @@ static struct ata_queued_cmd *ata_qc_new
struct ata_queued_cmd *qc = NULL;
unsigned int i;
- for (i = 0; i < ATA_MAX_QUEUE; i++)
+ /* the last tag is reserved for internal command. */
+ for (i = 0; i < ATA_MAX_QUEUE - 1; i++)
if (!test_and_set_bit(i, &ap->qactive)) {
qc = ata_qc_from_tag(ap, i);
break;
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 111bae9..e814f38 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -107,7 +107,9 @@ enum {
LIBATA_MAX_PRD = ATA_MAX_PRD / 2,
ATA_MAX_PORTS = 8,
ATA_DEF_QUEUE = 1,
- ATA_MAX_QUEUE = 1,
+ /* tag ATA_MAX_QUEUE - 1 is reserved for internal commands */
+ ATA_MAX_QUEUE = 2,
+ ATA_TAG_INTERNAL = ATA_MAX_QUEUE - 1,
ATA_MAX_SECTORS = 200, /* FIXME */
ATA_MAX_BUS = 2,
ATA_DEF_BUSY_WAIT = 10000,
@@ -697,6 +699,11 @@ static inline unsigned int ata_tag_valid
return (tag < ATA_MAX_QUEUE) ? 1 : 0;
}
+static inline unsigned int ata_tag_internal(unsigned int tag)
+{
+ return tag == ATA_MAX_QUEUE - 1;
+}
+
static inline unsigned int ata_class_enabled(unsigned int class)
{
return class == ATA_DEV_ATA || class == ATA_DEV_ATAPI;
--
1.2.4
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