block: remove QUEUE_FLAG_SCSI_PASSTHROUGH

Export scsi_device_from_queue for use with pktcdvd and use that instead
of the otherwise unused QUEUE_FLAG_SCSI_PASSTHROUGH queue flag.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20211021060607.264371-8-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-mq-debugfs.c

@@ -124,7 +124,6 @@ static const char *const blk_queue_flag_name[] = {
 	QUEUE_FLAG_NAME(STATS),
 	QUEUE_FLAG_NAME(POLL_STATS),
 	QUEUE_FLAG_NAME(REGISTERED),
-	QUEUE_FLAG_NAME(SCSI_PASSTHROUGH),
 	QUEUE_FLAG_NAME(QUIESCED),
 	QUEUE_FLAG_NAME(PCI_P2PDMA),
 	QUEUE_FLAG_NAME(ZONE_RESETALL),

drivers/block/pktcdvd.c

@@ -2536,6 +2536,7 @@ static int pkt_new_dev(struct pktcdvd_device *pd, dev_t dev)
 	int i;
 	char b[BDEVNAME_SIZE];
 	struct block_device *bdev;
+	struct scsi_device *sdev;
 
 	if (pd->pkt_dev == dev) {
 		pkt_err(pd, "recursive setup not allowed\n");
@@ -2559,10 +2560,12 @@ static int pkt_new_dev(struct pktcdvd_device *pd, dev_t dev)
 	bdev = blkdev_get_by_dev(dev, FMODE_READ | FMODE_NDELAY, NULL);
 	if (IS_ERR(bdev))
 		return PTR_ERR(bdev);
-	if (!blk_queue_scsi_passthrough(bdev_get_queue(bdev))) {
+	sdev = scsi_device_from_queue(bdev->bd_disk->queue);
+	if (!sdev) {
 		blkdev_put(bdev, FMODE_READ | FMODE_NDELAY);
 		return -EINVAL;
 	}
+	put_device(&sdev->sdev_gendev);
 
 	/* This is safe, since we have a reference from open(). */
 	__module_get(THIS_MODULE);

drivers/scsi/scsi_lib.c

@@ -1967,6 +1967,14 @@ struct scsi_device *scsi_device_from_queue(struct request_queue *q)
 
 	return sdev;
 }
+/*
+ * pktcdvd should have been integrated into the SCSI layers, but for historical
+ * reasons like the old IDE driver it isn't.  This export allows it to safely
+ * probe if a given device is a SCSI one and only attach to that.
+ */
+#ifdef CONFIG_CDROM_PKTCDVD_MODULE
+EXPORT_SYMBOL_GPL(scsi_device_from_queue);
+#endif
 
 /**
  * scsi_block_requests - Utility function used by low-level drivers to prevent

drivers/scsi/scsi_scan.c

@@ -280,7 +280,6 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
 	sdev->request_queue = q;
 	q->queuedata = sdev;
 	__scsi_init_queue(sdev->host, q);
-	blk_queue_flag_set(QUEUE_FLAG_SCSI_PASSTHROUGH, q);
 	WARN_ON_ONCE(!blk_get_queue(q));
 
 	depth = sdev->host->cmd_per_lun ?: 1;

include/linux/blkdev.h

@@ -357,7 +357,6 @@ struct request_queue {
 #define QUEUE_FLAG_STATS	20	/* track IO start and completion times */
 #define QUEUE_FLAG_POLL_STATS	21	/* collecting stats for hybrid polling */
 #define QUEUE_FLAG_REGISTERED	22	/* queue has been registered to a disk */
-#define QUEUE_FLAG_SCSI_PASSTHROUGH 23	/* queue supports SCSI commands */
 #define QUEUE_FLAG_QUIESCED	24	/* queue has been quiesced */
 #define QUEUE_FLAG_PCI_P2PDMA	25	/* device supports PCI p2p requests */
 #define QUEUE_FLAG_ZONE_RESETALL 26	/* supports Zone Reset All */
@@ -391,8 +390,6 @@ bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q);
 #define blk_queue_secure_erase(q) \
 	(test_bit(QUEUE_FLAG_SECERASE, &(q)->queue_flags))
 #define blk_queue_dax(q)	test_bit(QUEUE_FLAG_DAX, &(q)->queue_flags)
-#define blk_queue_scsi_passthrough(q)	\
-	test_bit(QUEUE_FLAG_SCSI_PASSTHROUGH, &(q)->queue_flags)
 #define blk_queue_pci_p2pdma(q)	\
 	test_bit(QUEUE_FLAG_PCI_P2PDMA, &(q)->queue_flags)
 #ifdef CONFIG_BLK_RQ_ALLOC_TIME