libata: switch to using block layer tagging support

libata currently has a pretty dumb ATA_MAX_QUEUE loop for finding
a free tag to use. Instead of fixing that up, convert libata to
using block layer tagging - gets rid of code in libata, and is also
much faster.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 31 insertions, 65 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index bbb3cae57492..8cb0b360bfd8 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -1713,8 +1713,6 @@ unsigned ata_exec_internal_sg(struct ata_device *dev,
         else
                 tag = 0;
 
-        if (test_and_set_bit(tag, &ap->qc_allocated))
-                BUG();
         qc = __ata_qc_from_tag(ap, tag);
 
         qc->tag = tag;
@@ -4553,37 +4551,6 @@ void swap_buf_le16(u16 *buf, unsigned int buf_words)
 }
 
 /**
- *      ata_qc_new - Request an available ATA command, for queueing
- *      @ap: Port associated with device @dev
- *      @dev: Device from whom we request an available command structure
- *
- *      LOCKING:
- *      None.
- */
-
-static struct ata_queued_cmd *ata_qc_new(struct ata_port *ap)
-{
-        struct ata_queued_cmd *qc = NULL;
-        unsigned int i;
-
-        /* no command while frozen */
-        if (unlikely(ap->pflags & ATA_PFLAG_FROZEN))
-                return NULL;
-
-        /* the last tag is reserved for internal command. */
-        for (i = 0; i < ATA_MAX_QUEUE - 1; i++)
-                if (!test_and_set_bit(i, &ap->qc_allocated)) {
-                        qc = __ata_qc_from_tag(ap, i);
-                        break;
-                }
-
-        if (qc)
-                qc->tag = i;
-
-        return qc;
-}
-
-/**
  *      ata_qc_new_init - Request an available ATA command, and initialize it
  *      @dev: Device from whom we request an available command structure
  *
@@ -4591,16 +4558,20 @@ static struct ata_queued_cmd *ata_qc_new(struct ata_port *ap)
  *      None.
  */
 
-struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev)
+struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev, int tag)
 {
         struct ata_port *ap = dev->link->ap;
         struct ata_queued_cmd *qc;
 
-        qc = ata_qc_new(ap);
+        if (unlikely(ap->pflags & ATA_PFLAG_FROZEN))
+                return NULL;
+
+        qc = __ata_qc_from_tag(ap, tag);
         if (qc) {
                 qc->scsicmd = NULL;
                 qc->ap = ap;
                 qc->dev = dev;
+                qc->tag = tag;
 
                 ata_qc_reinit(qc);
         }
@@ -4608,31 +4579,6 @@ struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev)
         return qc;
 }
 
-/**
- *      ata_qc_free - free unused ata_queued_cmd
- *      @qc: Command to complete
- *
- *      Designed to free unused ata_queued_cmd object
- *      in case something prevents using it.
- *
- *      LOCKING:
- *      spin_lock_irqsave(host lock)
- */
-void ata_qc_free(struct ata_queued_cmd *qc)
-{
-        struct ata_port *ap = qc->ap;
-        unsigned int tag;
-
-        WARN_ON(qc == NULL);    /* ata_qc_from_tag _might_ return NULL */
-
-        qc->flags = 0;
-        tag = qc->tag;
-        if (likely(ata_tag_valid(tag))) {
-                qc->tag = ATA_TAG_POISON;
-                clear_bit(tag, &ap->qc_allocated);
-        }
-}
-
 void __ata_qc_complete(struct ata_queued_cmd *qc)
 {
         struct ata_port *ap = qc->ap;
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 5d312dc9be9f..d5b9b7266c8b 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -708,7 +708,7 @@ static struct ata_queued_cmd *ata_scsi_qc_new(struct ata_device *dev,
 {
         struct ata_queued_cmd *qc;
 
-        qc = ata_qc_new_init(dev);
+        qc = ata_qc_new_init(dev, cmd->request->tag);
         if (qc) {
                 qc->scsicmd = cmd;
                 qc->scsidone = done;
@@ -1103,7 +1103,8 @@ static int ata_scsi_dev_config(struct scsi_device *sdev,
 
                 depth = min(sdev->host->can_queue, ata_id_queue_depth(dev->id));
                 depth = min(ATA_MAX_QUEUE - 1, depth);
-                scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
+                scsi_set_tag_type(sdev, MSG_SIMPLE_TAG);
+                scsi_activate_tcq(sdev, depth);
         }
 
         return 0;
@@ -1943,6 +1944,11 @@ static unsigned int ata_scsiop_inq_std(struct ata_scsi_args *args, u8 *rbuf)
                 hdr[1] |= (1 << 7);
 
         memcpy(rbuf, hdr, sizeof(hdr));
+
+        /* if ncq, set tags supported */
+        if (ata_id_has_ncq(args->id))
+                rbuf[7] |= (1 << 1);
+
         memcpy(&rbuf[8], "ATA     ", 8);
         ata_id_string(args->id, &rbuf[16], ATA_ID_PROD, 16);
         ata_id_string(args->id, &rbuf[32], ATA_ID_FW_REV, 4);
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index fe2839e58774..d3831d39bdaa 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -74,7 +74,7 @@ extern struct ata_link *ata_dev_phys_link(struct ata_device *dev);
 extern void ata_force_cbl(struct ata_port *ap);
 extern u64 ata_tf_to_lba(const struct ata_taskfile *tf);
 extern u64 ata_tf_to_lba48(const struct ata_taskfile *tf);
-extern struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev);
+extern struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev, int tag);
 extern int ata_build_rw_tf(struct ata_taskfile *tf, struct ata_device *dev,
                            u64 block, u32 n_block, unsigned int tf_flags,
                            unsigned int tag);
@@ -103,7 +103,6 @@ extern int ata_dev_configure(struct ata_device *dev);
 extern int sata_down_spd_limit(struct ata_link *link);
 extern int ata_down_xfermask_limit(struct ata_device *dev, unsigned int sel);
 extern void ata_sg_clean(struct ata_queued_cmd *qc);
-extern void ata_qc_free(struct ata_queued_cmd *qc);
 extern void ata_qc_issue(struct ata_queued_cmd *qc);
 extern void __ata_qc_complete(struct ata_queued_cmd *qc);
 extern int atapi_check_dma(struct ata_queued_cmd *qc);
@@ -119,6 +118,22 @@ extern struct ata_port *ata_port_alloc(struct ata_host *host);
 extern void ata_dev_enable_pm(struct ata_device *dev, enum link_pm policy);
 extern void ata_lpm_schedule(struct ata_port *ap, enum link_pm);
 
+/**
+ *      ata_qc_free - free unused ata_queued_cmd
+ *      @qc: Command to complete
+ *
+ *      Designed to free unused ata_queued_cmd object
+ *      in case something prevents using it.
+ *
+ *      LOCKING:
+ *      spin_lock_irqsave(host lock)
+ */
+static inline void ata_qc_free(struct ata_queued_cmd *qc)
+{
+        qc->flags = 0;
+        qc->tag = ATA_TAG_POISON;
+}
+
 /* libata-acpi.c */
 #ifdef CONFIG_ATA_ACPI
 extern void ata_acpi_associate_sata_port(struct ata_port *ap);
diff --git a/include/linux/libata.h b/include/linux/libata.h
index c261aa0584b1..507f53ef8038 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -695,7 +695,6 @@ struct ata_port {
         unsigned int            cbl;    /* cable type; ATA_CBL_xxx */
 
         struct ata_queued_cmd   qcmd[ATA_MAX_QUEUE];
-        unsigned long           qc_allocated;
         unsigned int            qc_active;
         int                     nr_active_links; /* #links with active qcs */