sr: convert to the atomic queue limits API

Assign all queue limits through a local queue_limits variable and
queue_limits_commit_update so that we can't race updating them from
multiple places, and free the queue when updating them so that
in-progress I/O submissions don't see half-updated limits.

Also use the chance to clean up variable names to standard ones.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20240531074837.1648501-13-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: Christoph Hellwig

drivers/scsi/sr.c

@@ -111,7 +111,7 @@ static struct lock_class_key sr_bio_compl_lkclass;
 static int sr_open(struct cdrom_device_info *, int);
 static void sr_release(struct cdrom_device_info *);
 
-static void get_sectorsize(struct scsi_cd *);
+static int get_sectorsize(struct scsi_cd *);
 static int get_capabilities(struct scsi_cd *);
 
 static unsigned int sr_check_events(struct cdrom_device_info *cdi,
@@ -473,15 +473,15 @@ static blk_status_t sr_init_command(struct scsi_cmnd *SCpnt)
 	return BLK_STS_IOERR;
 }
 
-static void sr_revalidate_disk(struct scsi_cd *cd)
+static int sr_revalidate_disk(struct scsi_cd *cd)
 {
 	struct scsi_sense_hdr sshdr;
 
 	/* if the unit is not ready, nothing more to do */
 	if (scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr))
-		return;
+		return 0;
 	sr_cd_check(&cd->cdi);
-	get_sectorsize(cd);
+	return get_sectorsize(cd);
 }
 
 static int sr_block_open(struct gendisk *disk, blk_mode_t mode)
@@ -494,13 +494,16 @@ static int sr_block_open(struct gendisk *disk, blk_mode_t mode)
 		return -ENXIO;
 
 	scsi_autopm_get_device(sdev);
-	if (disk_check_media_change(disk))
-		sr_revalidate_disk(cd);
+	if (disk_check_media_change(disk)) {
+		ret = sr_revalidate_disk(cd);
+		if (ret)
+			goto out;
+	}
 
 	mutex_lock(&cd->lock);
 	ret = cdrom_open(&cd->cdi, mode);
 	mutex_unlock(&cd->lock);
-
+out:
 	scsi_autopm_put_device(sdev);
 	if (ret)
 		scsi_device_put(cd->device);
@@ -685,7 +688,9 @@ static int sr_probe(struct device *dev)
 	blk_pm_runtime_init(sdev->request_queue, dev);
 
 	dev_set_drvdata(dev, cd);
-	sr_revalidate_disk(cd);
+	error = sr_revalidate_disk(cd);
+	if (error)
+		goto unregister_cdrom;
 
 	error = device_add_disk(&sdev->sdev_gendev, disk, NULL);
 	if (error)
@@ -714,13 +719,14 @@ static int sr_probe(struct device *dev)
 }
 
 
-static void get_sectorsize(struct scsi_cd *cd)
+static int get_sectorsize(struct scsi_cd *cd)
 {
+	struct request_queue *q = cd->device->request_queue;
 	static const u8 cmd[10] = { READ_CAPACITY };
 	unsigned char buffer[8] = { };
-	int the_result;
+	struct queue_limits lim;
+	int err;
 	int sector_size;
-	struct request_queue *queue;
 	struct scsi_failure failure_defs[] = {
 		{
 			.result = SCMD_FAILURE_RESULT_ANY,
@@ -736,10 +742,10 @@ static void get_sectorsize(struct scsi_cd *cd)
 	};
 
 	/* Do the command and wait.. */
-	the_result = scsi_execute_cmd(cd->device, cmd, REQ_OP_DRV_IN, buffer,
+	err = scsi_execute_cmd(cd->device, cmd, REQ_OP_DRV_IN, buffer,
 				      sizeof(buffer), SR_TIMEOUT, MAX_RETRIES,
 				      &exec_args);
-	if (the_result) {
+	if (err) {
 		cd->capacity = 0x1fffff;
 		sector_size = 2048;	/* A guess, just in case */
 	} else {
@@ -789,10 +795,12 @@ static void get_sectorsize(struct scsi_cd *cd)
 		set_capacity(cd->disk, cd->capacity);
 	}
 
-	queue = cd->device->request_queue;
-	blk_queue_logical_block_size(queue, sector_size);
-
-	return;
+	lim = queue_limits_start_update(q);
+	lim.logical_block_size = sector_size;
+	blk_mq_freeze_queue(q);
+	err = queue_limits_commit_update(q, &lim);
+	blk_mq_unfreeze_queue(q);
+	return err;
 }
 
 static int get_capabilities(struct scsi_cd *cd)