[PATCH 1/2] libata: switch to using block layer tagging support

[Jens Axboe <jens.axboe@oracle.com>]

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>
---
 drivers/ata/libata-core.c |   65 ++++----------------------------------------
 drivers/ata/libata-scsi.c |   23 ++++++++++++++-
 drivers/ata/libata.h      |   19 ++++++++++++-
 include/linux/libata.h    |    1 -
 4 files changed, 44 insertions(+), 64 deletions(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 8de0081..cc67307 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -1789,8 +1789,6 @@ 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;
@@ -4783,36 +4781,6 @@ void swap_buf_le16(u16 *buf, unsigned int buf_words)
 }
 
 /**
- *	ata_qc_new - Request an available ATA command, for queueing
- *	@ap: target port
- *
- *	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
  *
@@ -4820,16 +4788,20 @@ 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);
 	}
@@ -4837,31 +4809,6 @@ 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_ONCE(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 2733b0c..04f7a8d 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -742,7 +742,11 @@ static struct ata_queued_cmd *ata_scsi_qc_new(struct ata_device *dev,
 {
 	struct ata_queued_cmd *qc;
 
-	qc = ata_qc_new_init(dev);
+	if (cmd->request->tag != -1)
+		qc = ata_qc_new_init(dev, cmd->request->tag);
+	else
+		qc = ata_qc_new_init(dev, 0);
+
 	if (qc) {
 		qc->scsicmd = cmd;
 		qc->scsidone = done;
@@ -1137,7 +1141,17 @@ 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);
+
+		/*
+		 * If this device is behind a port multiplier, we have
+		 * to share the tag map between all devices on that PMP.
+		 * Set up the shared tag map here and we get automatic.
+		 */
+		if (dev->link->ap->pmp_link)
+			scsi_init_shared_tag_map(sdev->host, ATA_MAX_QUEUE - 1);
+
+		scsi_set_tag_type(sdev, MSG_SIMPLE_TAG);
+		scsi_activate_tcq(sdev, depth);
 	}
 
 	return 0;
@@ -1990,6 +2004,11 @@ 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 89a1e00..bad444b 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);
@@ -100,7 +100,6 @@ extern int ata_dev_configure(struct ata_device *dev);
 extern int sata_down_spd_limit(struct ata_link *link, u32 spd_limit);
 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);
@@ -116,6 +115,22 @@ 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 3d501db..cf1e54e 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -716,7 +716,6 @@ 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 */
 
-- 
1.6.3.rc0.1.gf800

-- 
Jens Axboe