libata: allow sata_sil24 to opt-out of tag ordered submission

commit 72dd299d5039a336493993dcc63413cf31d0e662 upstream.

Ronny reports: https://bugzilla.kernel.org/show_bug.cgi?id=87101
    "Since commit 8a4aeec8d "libata/ahci: accommodate tag ordered
    controllers" the access to the harddisk on the first SATA-port is
    failing on its first access. The access to the harddisk on the
    second port is working normal.

    When reverting the above commit, access to both harddisks is working
    fine again."

Maintain tag ordered submission as the default, but allow sata_sil24 to
continue with the old behavior.

Cc: Tejun Heo <tj@kernel.org>
Reported-by: Ronny Hegewald <Ronny.Hegewald@online.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index c5ba15af87d3eccd8553f0daab21a4f5237e8d91..485f7eab0d4b90cc63e2ee070f3aa344f1a89e26 100644 (file)
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4740,7 +4740,10 @@ static struct ata_queued_cmd *ata_qc_new(struct ata_port *ap)
                return NULL;
 
        for (i = 0, tag = ap->last_tag + 1; i < max_queue; i++, tag++) {
-               tag = tag < max_queue ? tag : 0;
+               if (ap->flags & ATA_FLAG_LOWTAG)
+                       tag = i;
+               else
+                       tag = tag < max_queue ? tag : 0;
 
                /* the last tag is reserved for internal command. */
                if (tag == ATA_TAG_INTERNAL)

diff --git a/drivers/ata/sata_sil24.c b/drivers/ata/sata_sil24.c
index d81b20ddb52736de9f9b7e15126382ebdeec2e37..ea655949023f4a6304096a33724ed2d2d8ed56c3 100644 (file)
--- a/drivers/ata/sata_sil24.c
+++ b/drivers/ata/sata_sil24.c
@@ -246,7 +246,7 @@ enum {
        /* host flags */
        SIL24_COMMON_FLAGS      = ATA_FLAG_SATA | ATA_FLAG_PIO_DMA |
                                  ATA_FLAG_NCQ | ATA_FLAG_ACPI_SATA |
-                                 ATA_FLAG_AN | ATA_FLAG_PMP,
+                                 ATA_FLAG_AN | ATA_FLAG_PMP | ATA_FLAG_LOWTAG,
        SIL24_FLAG_PCIX_IRQ_WOC = (1 << 24), /* IRQ loss errata on PCI-X */
 
        IRQ_STAT_4PORTS         = 0xf,

diff --git a/include/linux/libata.h b/include/linux/libata.h
index bd5fefeaf548670d706af4b850121ed28b7091df..fe0bf8dc83bb9ffdae94d017887da318e202d0a8 100644 (file)
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -230,6 +230,7 @@ enum {
        ATA_FLAG_SW_ACTIVITY    = (1 << 22), /* driver supports sw activity
                                              * led */
        ATA_FLAG_NO_DIPM        = (1 << 23), /* host not happy with DIPM */
+       ATA_FLAG_LOWTAG         = (1 << 24), /* host wants lowest available tag */
 
        /* bits 24:31 of ap->flags are reserved for LLD specific flags */