From: Tejun Heo Date: Sat, 11 Nov 2006 11:10:45 +0000 (+0900) Subject: [PATCH] libata: use FLUSH_EXT only when driver is larger than LBA28 limit X-Git-Tag: v2.6.20-rc1~34^2~40^2~9^2~53 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6fc49adb9417b9c793e8f88d485387bb89ceb733;p=linux-2.6 [PATCH] libata: use FLUSH_EXT only when driver is larger than LBA28 limit 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 Cc: Danny Kukawka Cc: Stefan Seyfried Signed-off-by: Jeff Garzik --- diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index f531a89c26..d94b8a02c3 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -1457,6 +1457,10 @@ int ata_dev_configure(struct ata_device *dev) 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 *dev) 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 f13dd07a53..7a55c2e4ea 100644 --- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -1027,8 +1027,7 @@ static unsigned int ata_scsi_flush_xlat(struct ata_queued_cmd *qc, const u8 *scs 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 0d0ddeaee7..36e233cc38 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 */