block: move integrity information into queue_limits

Move the integrity information into the queue limits so that it can be
set atomically with other queue limits, and that the sysfs changes to
the read_verify and write_generate flags are properly synchronized.
This also allows to provide a more useful helper to stack the integrity
fields, although it still is separate from the main stacking function
as not all stackable devices want to inherit the integrity settings.
Even with that it greatly simplifies the code in md and dm.

Note that the integrity field is moved as-is into the queue limits.
While there are good arguments for removing the separate blk_integrity
structure, this would cause a lot of churn and might better be done at a
later time if desired.  However the integrity field in the queue_limits
structure is now unconditional so that various ifdefs can be avoided or
replaced with IS_ENABLED().  Given that tiny size of it that seems like
a worthwhile trade off.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20240613084839.1044015-13-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 14 insertions, 20 deletions

diff --git a/drivers/scsi/sd_dif.c b/drivers/scsi/sd_dif.c
index 6f0921c7db78..ae6ce6f5d622 100644
--- a/drivers/scsi/sd_dif.c
+++ b/drivers/scsi/sd_dif.c
@@ -24,14 +24,15 @@
 /*
  * Configure exchange of protection information between OS and HBA.
  */
-void sd_dif_config_host(struct scsi_disk *sdkp)
+void sd_dif_config_host(struct scsi_disk *sdkp, struct queue_limits *lim)
 {
 	struct scsi_device *sdp = sdkp->device;
-	struct gendisk *disk = sdkp->disk;
 	u8 type = sdkp->protection_type;
-	struct blk_integrity bi;
+	struct blk_integrity *bi = &lim->integrity;
 	int dif, dix;
 
+	memset(bi, 0, sizeof(*bi));
+
 	dif = scsi_host_dif_capable(sdp->host, type);
 	dix = scsi_host_dix_capable(sdp->host, type);
 
@@ -39,40 +40,33 @@ void sd_dif_config_host(struct scsi_disk *sdkp)
 		dif = 0; dix = 1;
 	}
 
-	if (!dix) {
-		blk_integrity_unregister(disk);
+	if (!dix)
 		return;
-	}
-
-	memset(&bi, 0, sizeof(bi));
 
 	/* Enable DMA of protection information */
 	if (scsi_host_get_guard(sdkp->device->host) & SHOST_DIX_GUARD_IP)
-		bi.csum_type = BLK_INTEGRITY_CSUM_IP;
+		bi->csum_type = BLK_INTEGRITY_CSUM_IP;
 	else
-		bi.csum_type = BLK_INTEGRITY_CSUM_CRC;
+		bi->csum_type = BLK_INTEGRITY_CSUM_CRC;
 
 	if (type != T10_PI_TYPE3_PROTECTION)
-		bi.flags |= BLK_INTEGRITY_REF_TAG;
+		bi->flags |= BLK_INTEGRITY_REF_TAG;
 
-	bi.tuple_size = sizeof(struct t10_pi_tuple);
+	bi->tuple_size = sizeof(struct t10_pi_tuple);
 
 	if (dif && type) {
-		bi.flags |= BLK_INTEGRITY_DEVICE_CAPABLE;
+		bi->flags |= BLK_INTEGRITY_DEVICE_CAPABLE;
 
 		if (!sdkp->ATO)
-			goto out;
+			return;
 
 		if (type == T10_PI_TYPE3_PROTECTION)
-			bi.tag_size = sizeof(u16) + sizeof(u32);
+			bi->tag_size = sizeof(u16) + sizeof(u32);
 		else
-			bi.tag_size = sizeof(u16);
+			bi->tag_size = sizeof(u16);
 	}
 
 	sd_first_printk(KERN_NOTICE, sdkp,
 			"Enabling DIX %s, application tag size %u bytes\n",
-			blk_integrity_profile_name(&bi), bi.tag_size);
-out:
-	blk_integrity_register(disk, &bi);
+			blk_integrity_profile_name(bi), bi->tag_size);
 }
-