libata: remove ATA_FLAG_LOWTAG

sata_sil24 for some reason pukes when tags are allocated round-robin
which helps tag ordered controllers.  To work around the issue,
72dd299d5039 ("libata: allow sata_sil24 to opt-out of tag ordered
submission") introduced ATA_FLAG_LOWTAG which tells libata tag
allocation to do lowest-first.

However, with the recent switch to blk-mq tag allocation, the liata
tag allocation code path is no longer used and the workaround is now
implemented in the block layer and selected by setting
scsi_host_template->tag_alloc_policy to BLK_TAG_ALLOC_FIFO.  See
9269e23496dd ("libata: make sata_sil24 use fifo tag allocator").

This leaves ATA_FLAG_LOWTAG withoout any actual user.  Remove it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Shaohua Li <shli@fb.com>
Cc: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index b061ba2c31d8f51408a15f2e019a3c328e882815..fd9be1756f0d10dc48866cf727221135b94efc47 100644 (file)
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -4240,10 +4240,7 @@ int ata_sas_allocate_tag(struct ata_port *ap)
        unsigned int i, tag;
 
        for (i = 0, tag = ap->sas_last_tag + 1; i < max_queue; i++, tag++) {
-               if (ap->flags & ATA_FLAG_LOWTAG)
-                       tag = 1;
-               else
-                       tag = tag < max_queue ? tag : 0;
+               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 ba2667fa0528ff1f2138c438bfe72d10c6757c87..52428971ba9468e98da6db30b5b60f2ca6f74fde 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_LOWTAG,
+                                 ATA_FLAG_AN | ATA_FLAG_PMP,
        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 fc03efa64ffe58ae9aa81e77bf60e5d7b4acc6c7..ebe132a4873cb28ae2596e7064789b06ce85eb98 100644 (file)
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -231,7 +231,6 @@ 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 */