ide-pm: don't abuse rq->data

Impact: cleanup rq->data usage

ide-pm uses rq->data to carry pointer to struct request_pm_state
through request queue and rq->special is used to carray pointer to
local struct ide_cmd, which isn't necessary.  Use rq->special for
request_pm_state instead and use local ide_cmd in
ide_start_power_step().
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>

drivers/ide/ide-io.c

@@ -368,7 +368,7 @@ static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq)
 		if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE)
 			return execute_drive_cmd(drive, rq);
 		else if (blk_pm_request(rq)) {
-			struct request_pm_state *pm = rq->data;
+			struct request_pm_state *pm = rq->special;
 #ifdef DEBUG_PM
 			printk("%s: start_power_step(step: %d)\n",
 				drive->name, pm->pm_step);

drivers/ide/ide-pm.c

@@ -7,7 +7,6 @@ int generic_ide_suspend(struct device *dev, pm_message_t mesg)
 	ide_hwif_t *hwif = drive->hwif;
 	struct request *rq;
 	struct request_pm_state rqpm;
-	struct ide_cmd cmd;
 	int ret;
 
 	/* call ACPI _GTM only once */
@@ -15,11 +14,9 @@ int generic_ide_suspend(struct device *dev, pm_message_t mesg)
 		ide_acpi_get_timing(hwif);
 
 	memset(&rqpm, 0, sizeof(rqpm));
-	memset(&cmd, 0, sizeof(cmd));
 	rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
 	rq->cmd_type = REQ_TYPE_PM_SUSPEND;
-	rq->special = &cmd;
-	rq->data = &rqpm;
+	rq->special = &rqpm;
 	rqpm.pm_step = IDE_PM_START_SUSPEND;
 	if (mesg.event == PM_EVENT_PRETHAW)
 		mesg.event = PM_EVENT_FREEZE;
@@ -41,7 +38,6 @@ int generic_ide_resume(struct device *dev)
 	ide_hwif_t *hwif = drive->hwif;
 	struct request *rq;
 	struct request_pm_state rqpm;
-	struct ide_cmd cmd;
 	int err;
 
 	/* call ACPI _PS0 / _STM only once */
@@ -53,12 +49,10 @@ int generic_ide_resume(struct device *dev)
 	ide_acpi_exec_tfs(drive);
 
 	memset(&rqpm, 0, sizeof(rqpm));
-	memset(&cmd, 0, sizeof(cmd));
 	rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
 	rq->cmd_type = REQ_TYPE_PM_RESUME;
 	rq->cmd_flags |= REQ_PREEMPT;
-	rq->special = &cmd;
-	rq->data = &rqpm;
+	rq->special = &rqpm;
 	rqpm.pm_step = IDE_PM_START_RESUME;
 	rqpm.pm_state = PM_EVENT_ON;
 
@@ -77,7 +71,7 @@ int generic_ide_resume(struct device *dev)
 
 void ide_complete_power_step(ide_drive_t *drive, struct request *rq)
 {
-	struct request_pm_state *pm = rq->data;
+	struct request_pm_state *pm = rq->special;
 
 #ifdef DEBUG_PM
 	printk(KERN_INFO "%s: complete_power_step(step: %d)\n",
@@ -107,10 +101,8 @@ void ide_complete_power_step(ide_drive_t *drive, struct request *rq)
 
 ide_startstop_t ide_start_power_step(ide_drive_t *drive, struct request *rq)
 {
-	struct request_pm_state *pm = rq->data;
-	struct ide_cmd *cmd = rq->special;
-
-	memset(cmd, 0, sizeof(*cmd));
+	struct request_pm_state *pm = rq->special;
+	struct ide_cmd cmd = { };
 
 	switch (pm->pm_step) {
 	case IDE_PM_FLUSH_CACHE:	/* Suspend step 1 (flush cache) */
@@ -123,12 +115,12 @@ ide_startstop_t ide_start_power_step(ide_drive_t *drive, struct request *rq)
 			return ide_stopped;
 		}
 		if (ata_id_flush_ext_enabled(drive->id))
-			cmd->tf.command = ATA_CMD_FLUSH_EXT;
+			cmd.tf.command = ATA_CMD_FLUSH_EXT;
 		else
-			cmd->tf.command = ATA_CMD_FLUSH;
+			cmd.tf.command = ATA_CMD_FLUSH;
 		goto out_do_tf;
 	case IDE_PM_STANDBY:		/* Suspend step 2 (standby) */
-		cmd->tf.command = ATA_CMD_STANDBYNOW1;
+		cmd.tf.command = ATA_CMD_STANDBYNOW1;
 		goto out_do_tf;
 	case IDE_PM_RESTORE_PIO:	/* Resume step 1 (restore PIO) */
 		ide_set_max_pio(drive);
@@ -141,7 +133,7 @@ ide_startstop_t ide_start_power_step(ide_drive_t *drive, struct request *rq)
 			ide_complete_power_step(drive, rq);
 		return ide_stopped;
 	case IDE_PM_IDLE:		/* Resume step 2 (idle) */
-		cmd->tf.command = ATA_CMD_IDLEIMMEDIATE;
+		cmd.tf.command = ATA_CMD_IDLEIMMEDIATE;
 		goto out_do_tf;
 	case IDE_PM_RESTORE_DMA:	/* Resume step 3 (restore DMA) */
 		/*
@@ -163,11 +155,11 @@ ide_startstop_t ide_start_power_step(ide_drive_t *drive, struct request *rq)
 	return ide_stopped;
 
 out_do_tf:
-	cmd->valid.out.tf = IDE_VALID_OUT_TF | IDE_VALID_DEVICE;
-	cmd->valid.in.tf  = IDE_VALID_IN_TF  | IDE_VALID_DEVICE;
-	cmd->protocol = ATA_PROT_NODATA;
+	cmd.valid.out.tf = IDE_VALID_OUT_TF | IDE_VALID_DEVICE;
+	cmd.valid.in.tf  = IDE_VALID_IN_TF  | IDE_VALID_DEVICE;
+	cmd.protocol = ATA_PROT_NODATA;
 
-	return do_rw_taskfile(drive, cmd);
+	return do_rw_taskfile(drive, &cmd);
 }
 
 /**
@@ -181,7 +173,7 @@ ide_startstop_t ide_start_power_step(ide_drive_t *drive, struct request *rq)
 void ide_complete_pm_rq(ide_drive_t *drive, struct request *rq)
 {
 	struct request_queue *q = drive->queue;
-	struct request_pm_state *pm = rq->data;
+	struct request_pm_state *pm = rq->special;
 	unsigned long flags;
 
 	ide_complete_power_step(drive, rq);
@@ -207,7 +199,7 @@ void ide_complete_pm_rq(ide_drive_t *drive, struct request *rq)
 
 void ide_check_pm_state(ide_drive_t *drive, struct request *rq)
 {
-	struct request_pm_state *pm = rq->data;
+	struct request_pm_state *pm = rq->special;
 
 	if (blk_pm_suspend_request(rq) &&
 	    pm->pm_step == IDE_PM_START_SUSPEND)