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>

1 files changed, 17 insertions, 2 deletions

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);