libata: use blk taging

libata uses its own tag management which is duplication and the
implementation is poor. And if we switch to blk-mq, tag is build-in.
It's time to switch to generic taging.

The SAS driver has its own tag management, and looks we can't directly
map the host controler tag to SATA tag. So I just bypassed the SAS case.

I changed the code/variable name for the tag management of libata to
make it self contained. Only sas will use it. Later if libsas implements
its tag management, the tag management code in libata can be deleted
easily.

Cc: Jens Axboe <axboe@fb.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 2d182413b1db..f23454762717 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -821,10 +821,10 @@ struct ata_port {
         unsigned int            cbl;    /* cable type; ATA_CBL_xxx */
 
         struct ata_queued_cmd   qcmd[ATA_MAX_QUEUE];
-        unsigned long           qc_allocated;
+        unsigned long           sas_tag_allocated; /* for sas tag allocation only */
         unsigned int            qc_active;
         int                     nr_active_links; /* #links with active qcs */
-        unsigned int            last_tag;       /* track next tag hw expects */
+        unsigned int            sas_last_tag;   /* track next tag hw expects */
 
         struct ata_link         link;           /* host default link */
         struct ata_link         *slave_link;    /* see ata_slave_link_init() */
@@ -1344,6 +1344,7 @@ extern struct device_attribute *ata_common_sdev_attrs[];
         .ioctl                  = ata_scsi_ioctl,               \
         .queuecommand           = ata_scsi_queuecmd,            \
         .can_queue              = ATA_DEF_QUEUE,                \
+        .tag_alloc_policy       = BLK_TAG_ALLOC_RR,             \
         .this_id                = ATA_SHT_THIS_ID,              \
         .cmd_per_lun            = ATA_SHT_CMD_PER_LUN,          \
         .emulated               = ATA_SHT_EMULATED,             \