libata: remove libata.spindown_compat

With STANDBYDOWN tracking added, libata.spindown_compat isn't
necessary anymore.  If userspace shutdown(8) issues STANDBYNOW, libata
warns.  If userspace shutdown(8) doesn't issue STANDBYNOW, libata does
the right thing.  Userspace can tell whether kernel supports spindown
by testing whether sysfs node manage_start_stop exists as before.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

Documentation/feature-removal-schedule.txt

@@ -328,21 +328,20 @@ Who:   Adrian Bunk <bunk@stusta.de>
 
 ---------------------------
 
-What: libata.spindown_compat module parameter
+What: libata spindown skipping and warning
 When: Dec 2008
-Why:  halt(8) synchronizes caches for and spins down libata disks
-      because libata didn't use to spin down disk on system halt
-      (only synchronized caches).
-      Spin down on system halt is now implemented and can be tested
-      using sysfs node /sys/class/scsi_disk/h:c:i:l/manage_start_stop.
+Why:  Some halt(8) implementations synchronize caches for and spin
+      down libata disks because libata didn't use to spin down disk on
+      system halt (only synchronized caches).
+      Spin down on system halt is now implemented.  sysfs node
+      /sys/class/scsi_disk/h:c:i:l/manage_start_stop is present if
+      spin down support is available.
       Because issuing spin down command to an already spun down disk
-      makes some disks spin up just to spin down again, the old
-      behavior needs to be maintained till userspace tool is updated
-      to check the sysfs node and not to spin down disks with the
-      node set to one.
-      This module parameter is to give userspace tool the time to
-      get updated and should be removed after userspace is
-      reasonably updated.
+      makes some disks spin up just to spin down again, libata tracks
+      device spindown status to skip the extra spindown command and
+      warn about it.
+      This is to give userspace tools the time to get updated and will
+      be removed after userspace is reasonably updated.
 Who:  Tejun Heo <htejun@gmail.com>
 
 ---------------------------

drivers/ata/libata-core.c

@@ -101,12 +101,6 @@ int libata_noacpi = 1;
 module_param_named(noacpi, libata_noacpi, int, 0444);
 MODULE_PARM_DESC(noacpi, "Disables the use of ACPI in suspend/resume when set");
 
-int ata_spindown_compat = 1;
-module_param_named(spindown_compat, ata_spindown_compat, int, 0644);
-MODULE_PARM_DESC(spindown_compat, "Enable backward compatible spindown "
-		 "behavior.  Will be removed.  More info can be found in "
-		 "Documentation/feature-removal-schedule.txt\n");
-
 MODULE_AUTHOR("Jeff Garzik");
 MODULE_DESCRIPTION("Library module for ATA devices");
 MODULE_LICENSE("GPL");

drivers/ata/libata-scsi.c

@@ -893,7 +893,7 @@ int ata_scsi_change_queue_depth(struct scsi_device *sdev, int queue_depth)
 	return queue_depth;
 }
 
-/* XXX: for ata_spindown_compat */
+/* XXX: for spindown warning */
 static void ata_delayed_done_timerfn(unsigned long arg)
 {
 	struct scsi_cmnd *scmd = (void *)arg;
@@ -901,7 +901,7 @@ static void ata_delayed_done_timerfn(unsigned long arg)
 	scmd->scsi_done(scmd);
 }
 
-/* XXX: for ata_spindown_compat */
+/* XXX: for spindown warning */
 static void ata_delayed_done(struct scsi_cmnd *scmd)
 {
 	static struct timer_list timer;
@@ -966,8 +966,7 @@ static unsigned int ata_scsi_start_stop_xlat(struct ata_queued_cmd *qc)
 		 * removed.  Read Documentation/feature-removal-schedule.txt
 		 * for more info.
 		 */
-		if (ata_spindown_compat &&
-		    (qc->dev->flags & ATA_DFLAG_SPUNDOWN) &&
+		if ((qc->dev->flags & ATA_DFLAG_SPUNDOWN) &&
 		    (system_state == SYSTEM_HALT ||
 		     system_state == SYSTEM_POWER_OFF)) {
 			static unsigned long warned = 0;
@@ -1395,7 +1394,7 @@ static void ata_scsi_qc_complete(struct ata_queued_cmd *qc)
 		}
 	}
 
-	/* XXX: track spindown state for spindown_compat */
+	/* XXX: track spindown state for spindown skipping and warning */
 	if (unlikely(qc->tf.command == ATA_CMD_STANDBY ||
 		     qc->tf.command == ATA_CMD_STANDBYNOW1))
 		qc->dev->flags |= ATA_DFLAG_SPUNDOWN;

drivers/ata/libata.h

@@ -58,7 +58,6 @@ extern int atapi_enabled;
 extern int atapi_dmadir;
 extern int libata_fua;
 extern int libata_noacpi;
-extern int ata_spindown_compat;
 extern struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev);
 extern int ata_build_rw_tf(struct ata_taskfile *tf, struct ata_device *dev,
 			   u64 block, u32 n_block, unsigned int tf_flags,