[PATCH v3 10/10] scsi: add support for user-meta interface

[Anuj Gupta <anuj20.g@xxxxxxxxxxx>]

Add support for sending user-meta buffer. Set tags to be checked
using flags specified by user/block-layer user and underlying DIF/DIX
configuration. Introduce BLK_INTEGRITY_APP_TAG to specify apptag.
This provides a way for upper layers to specify apptag checking.

Signed-off-by: Anuj Gupta <anuj20.g@xxxxxxxxxxx>
---
 block/bio-integrity.c         |  2 ++
 drivers/scsi/sd.c             | 25 +++++++++++++++++++++++--
 drivers/scsi/sd_dif.c         |  2 +-
 include/linux/blk-integrity.h |  1 +
 4 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index 02b766c2e57d..ff7de4fe74c4 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -492,6 +492,8 @@ bool bio_integrity_prep(struct bio *bio)
 		bip->bip_flags |= BIP_CHECK_GUARD;
 	if (bi->flags & BLK_INTEGRITY_REF_TAG)
 		bip->bip_flags |= BIP_CHECK_REFTAG;
+	if (bi->flags & BLK_INTEGRITY_APP_TAG)
+		bip->bip_flags |= BIP_CHECK_APPTAG;
 	if (bio_integrity_add_page(bio, virt_to_page(buf), len,
 			offset_in_page(buf)) < len) {
 		printk(KERN_ERR "could not attach integrity payload\n");
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 699f4f9674d9..6ebef140cec2 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -803,6 +803,23 @@ static unsigned int sd_prot_flag_mask(unsigned int prot_op)
 	return flag_mask[prot_op];
 }
 
+/*
+ * Can't check reftag alone or apptag alone
+ */
+static bool sd_prot_flags_valid(struct scsi_cmnd *scmd)
+{
+	struct request *rq = scsi_cmd_to_rq(scmd);
+	struct bio *bio = rq->bio;
+
+	if (bio_integrity_flagged(bio, BIP_CHECK_REFTAG) &&
+	    !bio_integrity_flagged(bio, BIP_CHECK_APPTAG))
+		return false;
+	if (!bio_integrity_flagged(bio, BIP_CHECK_REFTAG) &&
+	    bio_integrity_flagged(bio, BIP_CHECK_APPTAG))
+		return false;
+	return true;
+}
+
 static unsigned char sd_setup_protect_cmnd(struct scsi_cmnd *scmd,
 					   unsigned int dix, unsigned int dif)
 {
@@ -815,14 +832,16 @@ static unsigned char sd_setup_protect_cmnd(struct scsi_cmnd *scmd,
 		if (bio_integrity_flagged(bio, BIP_IP_CHECKSUM))
 			scmd->prot_flags |= SCSI_PROT_IP_CHECKSUM;
 
-		if (bio_integrity_flagged(bio, BIP_CTRL_NOCHECK) == false)
+		if (bio_integrity_flagged(bio, BIP_CTRL_NOCHECK) == false &&
+		    (bio_integrity_flagged(bio, BIP_CHECK_GUARD)))
 			scmd->prot_flags |= SCSI_PROT_GUARD_CHECK;
 	}
 
 	if (dif != T10_PI_TYPE3_PROTECTION) {	/* DIX/DIF Type 0, 1, 2 */
 		scmd->prot_flags |= SCSI_PROT_REF_INCREMENT;
 
-		if (bio_integrity_flagged(bio, BIP_CTRL_NOCHECK) == false)
+		if ((bio_integrity_flagged(bio, BIP_CTRL_NOCHECK) == false) &&
+			(!dix || bio_integrity_flagged(bio, BIP_CHECK_REFTAG)))
 			scmd->prot_flags |= SCSI_PROT_REF_CHECK;
 	}
 
@@ -1374,6 +1393,8 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *cmd)
 	dif = scsi_host_dif_capable(cmd->device->host, sdkp->protection_type);
 	dld = sd_cdl_dld(sdkp, cmd);
 
+	if (!sd_prot_flags_valid(cmd))
+		goto fail;
 	if (dif || dix)
 		protect = sd_setup_protect_cmnd(cmd, dix, dif);
 	else
diff --git a/drivers/scsi/sd_dif.c b/drivers/scsi/sd_dif.c
index ae6ce6f5d622..6c53e3b9d7d7 100644
--- a/drivers/scsi/sd_dif.c
+++ b/drivers/scsi/sd_dif.c
@@ -50,7 +50,7 @@ void sd_dif_config_host(struct scsi_disk *sdkp, struct queue_limits *lim)
 		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 | BLK_INTEGRITY_APP_TAG;
 
 	bi->tuple_size = sizeof(struct t10_pi_tuple);
 
diff --git a/include/linux/blk-integrity.h b/include/linux/blk-integrity.h
index 2ff65c933c50..865e0c4a7255 100644
--- a/include/linux/blk-integrity.h
+++ b/include/linux/blk-integrity.h
@@ -13,6 +13,7 @@ enum blk_integrity_flags {
 	BLK_INTEGRITY_DEVICE_CAPABLE	= 1 << 2,
 	BLK_INTEGRITY_REF_TAG		= 1 << 3,
 	BLK_INTEGRITY_STACKED		= 1 << 4,
+	BLK_INTEGRITY_APP_TAG		= 1 << 5,
 };
 
 const char *blk_integrity_profile_name(struct blk_integrity *bi);
-- 
2.25.1