scsi: sd: Reorganize DIF/DIX code to avoid calling revalidate twice

During device discovery we ended up calling revalidate twice and thus
requested the same parameters multiple times. This was originally necessary
due to the request_queue and gendisk needing to be instantiated to
configure the block integrity profile.

Since this dependency no longer exists, reorganize the integrity probing
code so it can be run once at the end of discovery and drop the superfluous
revalidate call. Postponing the registration step involves splitting
sd_read_protection() into two functions, one to read the device protection
type and one to configure the mode of operation.

As part of this cleanup, make the printing code a bit less verbose.

Link: https://lore.kernel.org/r/20220302053559.32147-14-martin.petersen@oracle.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/sd.c

@@ -2176,40 +2176,48 @@ static int sd_read_protection_type(struct scsi_disk *sdkp, unsigned char *buffer
 {
 	struct scsi_device *sdp = sdkp->device;
 	u8 type;
-	int ret = 0;
 
 	if (scsi_device_protection(sdp) == 0 || (buffer[12] & 1) == 0) {
 		sdkp->protection_type = 0;
-		return ret;
+		return 0;
 	}
 
 	type = ((buffer[12] >> 1) & 7) + 1; /* P_TYPE 0 = Type 1 */
 
-	if (type > T10_PI_TYPE3_PROTECTION)
-		ret = -ENODEV;
-	else if (scsi_host_dif_capable(sdp->host, type))
-		ret = 1;
-
-	if (sdkp->first_scan || type != sdkp->protection_type)
-		switch (ret) {
-		case -ENODEV:
-			sd_printk(KERN_ERR, sdkp, "formatted with unsupported" \
-				  " protection type %u. Disabling disk!\n",
-				  type);
-			break;
-		case 1:
-			sd_printk(KERN_NOTICE, sdkp,
-				  "Enabling DIF Type %u protection\n", type);
-			break;
-		case 0:
-			sd_printk(KERN_NOTICE, sdkp,
-				  "Disabling DIF Type %u protection\n", type);
-			break;
-		}
+	if (type > T10_PI_TYPE3_PROTECTION) {
+		sd_printk(KERN_ERR, sdkp, "formatted with unsupported"	\
+			  " protection type %u. Disabling disk!\n",
+			  type);
+		sdkp->protection_type = 0;
+		return -ENODEV;
+	}
 
 	sdkp->protection_type = type;
 
-	return ret;
+	return 0;
+}
+
+static void sd_config_protection(struct scsi_disk *sdkp)
+{
+	struct scsi_device *sdp = sdkp->device;
+
+	if (!sdkp->first_scan)
+		return;
+
+	sd_dif_config_host(sdkp);
+
+	if (!sdkp->protection_type)
+		return;
+
+	if (!scsi_host_dif_capable(sdp->host, sdkp->protection_type)) {
+		sd_printk(KERN_NOTICE, sdkp,
+			  "Disabling DIF Type %u protection\n",
+			  sdkp->protection_type);
+		sdkp->protection_type = 0;
+	}
+
+	sd_printk(KERN_NOTICE, sdkp, "Enabling DIF Type %u protection\n",
+		  sdkp->protection_type);
 }
 
 static void read_capacity_error(struct scsi_disk *sdkp, struct scsi_device *sdp,
@@ -3259,6 +3267,7 @@ static int sd_revalidate_disk(struct gendisk *disk)
 		sd_read_app_tag_own(sdkp, buffer);
 		sd_read_write_same(sdkp, buffer);
 		sd_read_security(sdkp, buffer);
+		sd_config_protection(sdkp);
 	}
 
 	/*
@@ -3518,11 +3527,6 @@ static int sd_probe(struct device *dev)
 		goto out;
 	}
 
-	if (sdkp->capacity)
-		sd_dif_config_host(sdkp);
-
-	sd_revalidate_disk(gd);
-
 	if (sdkp->security) {
 		sdkp->opal_dev = init_opal_dev(sdkp, &sd_sec_submit);
 		if (sdkp->opal_dev)

drivers/scsi/sd_dif.c

@@ -59,8 +59,6 @@ void sd_dif_config_host(struct scsi_disk *sdkp)
 			bi.profile = &t10_pi_type1_crc;
 
 	bi.tuple_size = sizeof(struct t10_pi_tuple);
-	sd_printk(KERN_NOTICE, sdkp,
-		  "Enabling DIX %s protection\n", bi.profile->name);
 
 	if (dif && type) {
 		bi.flags |= BLK_INTEGRITY_DEVICE_CAPABLE;
@@ -72,11 +70,11 @@ void sd_dif_config_host(struct scsi_disk *sdkp)
 			bi.tag_size = sizeof(u16) + sizeof(u32);
 		else
 			bi.tag_size = sizeof(u16);
-
-		sd_printk(KERN_NOTICE, sdkp, "DIF application tag size %u\n",
-			  bi.tag_size);
 	}
 
+	sd_printk(KERN_NOTICE, sdkp,
+		  "Enabling DIX %s, application tag size %u bytes\n",
+		  bi.profile->name, bi.tag_size);
 out:
 	blk_integrity_register(disk, &bi);
 }