Many drives support LBA48 even when its capacity is smaller than
1<<28, as LBA48 is required for many functionalities. FLUSH_EXT is
mandatory for drives w/ LBA48 support.
Interestingly, at least one of such drives (ST960812A) has problems
dealing with FLUSH_EXT. It eventually completes the command but takes
around 7 seconds to finish in many cases thus drastically slowing down
IO transactions. This seems to be a firmware bug which sneaked into
production probably because no other ATA driver including linux IDE
issues FLUSH_EXT to drives which report support for LBA48 & FLUSH_EXT
but is smaller than 1<<28 blocks.
This patch adds ATA_DFLAG_FLUSH_EXT which is set iff the drive
supports LBA48 & FLUSH_EXT and is larger than LBA28 limit. Both cache
flush paths are updated to issue FLUSH_EXT only when the flag is set.
Note that the changed behavior is more inline with the rest of libata.
libata prefers shorter commands whenever possible.
Signed-off-by: Tejun Heo <htejun@xxxxxxxxx>
Cc: Danny Kukawka <dkukawka@xxxxxxxxxx>
Cc: Stefan Seyfried <seife@xxxxxxxxxx>
---
* In ata_dev_configure(), use dev->n_sectors instead of reading it
directly from id.
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 9fdb266..e161036 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -1457,6 +1457,10 @@ int ata_dev_configure(struct ata_device
if (ata_id_has_lba48(id)) {
dev->flags |= ATA_DFLAG_LBA48;
lba_desc = "LBA48";
+
+ if (dev->n_sectors >= (1UL << 28) &&
+ ata_id_has_flush_ext(id))
+ dev->flags |= ATA_DFLAG_FLUSH_EXT;
}
/* config NCQ */
@@ -5128,7 +5132,7 @@ int ata_flush_cache(struct ata_device *d
if (!ata_try_flush_cache(dev))
return 0;
- if (ata_id_has_flush_ext(dev->id))
+ if (dev->flags & ATA_DFLAG_FLUSH_EXT)
cmd = ATA_CMD_FLUSH_EXT;
else
cmd = ATA_CMD_FLUSH;
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index a0b6ee1..2be51c6 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -1027,8 +1027,7 @@ static unsigned int ata_scsi_flush_xlat(
tf->flags |= ATA_TFLAG_DEVICE;
tf->protocol = ATA_PROT_NODATA;
- if ((qc->dev->flags & ATA_DFLAG_LBA48) &&
- (ata_id_has_flush_ext(qc->dev->id)))
+ if (qc->dev->flags & ATA_DFLAG_FLUSH_EXT)
tf->command = ATA_CMD_FLUSH_EXT;
else
tf->command = ATA_CMD_FLUSH;
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 0d0ddea..36e233c 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -140,6 +140,7 @@ enum {
ATA_DFLAG_LBA48 = (1 << 1), /* device supports LBA48 */
ATA_DFLAG_CDB_INTR = (1 << 2), /* device asserts INTRQ when ready for CDB */
ATA_DFLAG_NCQ = (1 << 3), /* device supports NCQ */
+ ATA_DFLAG_FLUSH_EXT = (1 << 4), /* do FLUSH_EXT instead of FLUSH */
ATA_DFLAG_CFG_MASK = (1 << 8) - 1,
ATA_DFLAG_PIO = (1 << 8), /* device limited to PIO mode */
-
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