[PATCH 09/23] scsi: use the atomic queue limits API in scsi_add_lun

[Christoph Hellwig <hch@lst.de>]

Switch scsi_add_lun to use the atomic queue limits API to update the
max_hw_sectors for devices with quirks.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/scsi_scan.c | 28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 205ab3b3ea89be..1ec4b309af726d 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -874,6 +874,7 @@ static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result,
 static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
 		blist_flags_t *bflags, int async)
 {
+	struct queue_limits lim;
 	int ret;
 
 	/*
@@ -1004,19 +1005,6 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
 	if (*bflags & BLIST_SELECT_NO_ATN)
 		sdev->select_no_atn = 1;
 
-	/*
-	 * Maximum 512 sector transfer length
-	 * broken RA4x00 Compaq Disk Array
-	 */
-	if (*bflags & BLIST_MAX_512)
-		blk_queue_max_hw_sectors(sdev->request_queue, 512);
-	/*
-	 * Max 1024 sector transfer length for targets that report incorrect
-	 * max/optimal lengths and relied on the old block layer safe default
-	 */
-	else if (*bflags & BLIST_MAX_1024)
-		blk_queue_max_hw_sectors(sdev->request_queue, 1024);
-
 	/*
 	 * Some devices may not want to have a start command automatically
 	 * issued when a device is added.
@@ -1077,6 +1065,20 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
 
 	transport_configure_device(&sdev->sdev_gendev);
 
+	/*
+	 * No need to freeze the queue as it isn't reachable to anyone else yet.
+	 */
+	lim = queue_limits_start_update(sdev->request_queue);
+	if (*bflags & BLIST_MAX_512)
+		lim.max_hw_sectors = 512;
+	else if (*bflags & BLIST_MAX_1024)
+		lim.max_hw_sectors = 1024;
+	ret = queue_limits_commit_update(sdev->request_queue, &lim);
+	if (ret) {
+		sdev_printk(KERN_ERR, sdev, "failed to apply queue limits.\n");
+		return SCSI_SCAN_NO_RESPONSE;
+	}
+
 	if (sdev->host->hostt->slave_configure) {
 		ret = sdev->host->hostt->slave_configure(sdev);
 		if (ret) {
-- 
2.39.2