Merge branch 'for-3.18/core' of git://git.kernel.dk/linux-block

Pull core block layer changes from Jens Axboe:
 "This is the core block IO pull request for 3.18.  Apart from the new
  and improved flush machinery for blk-mq, this is all mostly bug fixes
  and cleanups.

   - blk-mq timeout updates and fixes from Christoph.

   - Removal of REQ_END, also from Christoph.  We pass it through the
     ->queue_rq() hook for blk-mq instead, freeing up one of the request
     bits.  The space was overly tight on 32-bit, so Martin also killed
     REQ_KERNEL since it's no longer used.

   - blk integrity updates and fixes from Martin and Gu Zheng.

   - Update to the flush machinery for blk-mq from Ming Lei.  Now we
     have a per hardware context flush request, which both cleans up the
     code should scale better for flush intensive workloads on blk-mq.

   - Improve the error printing, from Rob Elliott.

   - Backing device improvements and cleanups from Tejun.

   - Fixup of a misplaced rq_complete() tracepoint from Hannes.

   - Make blk_get_request() return error pointers, fixing up issues
     where we NULL deref when a device goes bad or missing.  From Joe
     Lawrence.

   - Prep work for drastically reducing the memory consumption of dm
     devices from Junichi Nomura.  This allows creating clone bio sets
     without preallocating a lot of memory.

   - Fix a blk-mq hang on certain combinations of queue depths and
     hardware queues from me.

   - Limit memory consumption for blk-mq devices for crash dump
     scenarios and drivers that use crazy high depths (certain SCSI
     shared tag setups).  We now just use a single queue and limited
     depth for that"

* 'for-3.18/core' of git://git.kernel.dk/linux-block: (58 commits)
  block: Remove REQ_KERNEL
  blk-mq: allocate cpumask on the home node
  bio-integrity: remove the needless fail handle of bip_slab creating
  block: include func name in __get_request prints
  block: make blk_update_request print prefix match ratelimited prefix
  blk-merge: don't compute bi_phys_segments from bi_vcnt for cloned bio
  block: fix alignment_offset math that assumes io_min is a power-of-2
  blk-mq: Make bt_clear_tag() easier to read
  blk-mq: fix potential hang if rolling wakeup depth is too high
  block: add bioset_create_nobvec()
  block: use bio_clone_fast() in blk_rq_prep_clone()
  block: misplaced rq_complete tracepoint
  sd: Honor block layer integrity handling flags
  block: Replace strnicmp with strncasecmp
  block: Add T10 Protection Information functions
  block: Don't merge requests if integrity flags differ
  block: Integrity checksum flag
  block: Relocate bio integrity flags
  block: Add a disk flag to block integrity profile
  block: Add prefix to block integrity profile flags
  ...

23 files changed, 212 insertions, 367 deletions

diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
index 5c8e7fe07745..6b7e8d0fba99 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -247,7 +247,7 @@ static void mtip_async_complete(struct mtip_port *port,
 	if (unlikely(cmd->unaligned))
 		up(&port->cmd_slot_unal);
 
-	blk_mq_end_io(rq, status ? -EIO : 0);
+	blk_mq_end_request(rq, status ? -EIO : 0);
 }
 
 /*
@@ -3739,7 +3739,7 @@ static int mtip_submit_request(struct blk_mq_hw_ctx *hctx, struct request *rq)
 		int err;
 
 		err = mtip_send_trim(dd, blk_rq_pos(rq), blk_rq_sectors(rq));
-		blk_mq_end_io(rq, err);
+		blk_mq_end_request(rq, err);
 		return 0;
 	}
 
@@ -3775,13 +3775,16 @@ static bool mtip_check_unal_depth(struct blk_mq_hw_ctx *hctx,
 	return false;
 }
 
-static int mtip_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *rq)
+static int mtip_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *rq,
+		bool last)
 {
 	int ret;
 
 	if (unlikely(mtip_check_unal_depth(hctx, rq)))
 		return BLK_MQ_RQ_QUEUE_BUSY;
 
+	blk_mq_start_request(rq);
+
 	ret = mtip_submit_request(hctx, rq);
 	if (likely(!ret))
 		return BLK_MQ_RQ_QUEUE_OK;
diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
index 00d469c7f9f7..ac50a2931044 100644
--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -177,7 +177,7 @@ static void end_cmd(struct nullb_cmd *cmd)
 {
 	switch (queue_mode)  {
 	case NULL_Q_MQ:
-		blk_mq_end_io(cmd->rq, 0);
+		blk_mq_end_request(cmd->rq, 0);
 		return;
 	case NULL_Q_RQ:
 		INIT_LIST_HEAD(&cmd->rq->queuelist);
@@ -313,13 +313,16 @@ static void null_request_fn(struct request_queue *q)
 	}
 }
 
-static int null_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *rq)
+static int null_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *rq,
+		bool last)
 {
 	struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
 
 	cmd->rq = rq;
 	cmd->nq = hctx->driver_data;
 
+	blk_mq_start_request(rq);
+
 	null_handle_cmd(cmd);
 	return BLK_MQ_RQ_QUEUE_OK;
 }
diff --git a/drivers/block/paride/pd.c b/drivers/block/paride/pd.c
index fea7e76a00de..d48715b287e6 100644
--- a/drivers/block/paride/pd.c
+++ b/drivers/block/paride/pd.c
@@ -722,6 +722,8 @@ static int pd_special_command(struct pd_unit *disk,
 	int err = 0;
 
 	rq = blk_get_request(disk->gd->queue, READ, __GFP_WAIT);
+	if (IS_ERR(rq))
+		return PTR_ERR(rq);
 
 	rq->cmd_type = REQ_TYPE_SPECIAL;
 	rq->special = func;
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 758ac442c5b5..09e628dafd9d 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -704,6 +704,8 @@ static int pkt_generic_packet(struct pktcdvd_device *pd, struct packet_command *
 
 	rq = blk_get_request(q, (cgc->data_direction == CGC_DATA_WRITE) ?
 			     WRITE : READ, __GFP_WAIT);
+	if (IS_ERR(rq))
+		return PTR_ERR(rq);
 	blk_rq_set_block_pc(rq);
 
 	if (cgc->buflen) {
diff --git a/drivers/block/sx8.c b/drivers/block/sx8.c
index d5e2d12b9d9e..5d552857de41 100644
--- a/drivers/block/sx8.c
+++ b/drivers/block/sx8.c
@@ -568,7 +568,7 @@ static struct carm_request *carm_get_special(struct carm_host *host)
 		return NULL;
 
 	rq = blk_get_request(host->oob_q, WRITE /* bogus */, GFP_KERNEL);
-	if (!rq) {
+	if (IS_ERR(rq)) {
 		spin_lock_irqsave(&host->lock, flags);
 		carm_put_request(host, crq);
 		spin_unlock_irqrestore(&host->lock, flags);
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 930fee886917..c6a27d54ad62 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -129,7 +129,7 @@ static inline void virtblk_request_done(struct request *req)
 		req->errors = (error != 0);
 	}
 
-	blk_mq_end_io(req, error);
+	blk_mq_end_request(req, error);
 }
 
 static void virtblk_done(struct virtqueue *vq)
@@ -158,14 +158,14 @@ static void virtblk_done(struct virtqueue *vq)
 	spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
 }
 
-static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req)
+static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req,
+		bool last)
 {
 	struct virtio_blk *vblk = hctx->queue->queuedata;
 	struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
 	unsigned long flags;
 	unsigned int num;
 	int qid = hctx->queue_num;
-	const bool last = (req->cmd_flags & REQ_END) != 0;
 	int err;
 	bool notify = false;
 
@@ -199,6 +199,8 @@ static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req)
 		}
 	}
 
+	blk_mq_start_request(req);
+
 	num = blk_rq_map_sg(hctx->queue, vbr->req, vbr->sg);
 	if (num) {
 		if (rq_data_dir(vbr->req) == WRITE)
diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index 898b84bba28a..5d28a45d2960 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -2180,8 +2180,8 @@ static int cdrom_read_cdda_bpc(struct cdrom_device_info *cdi, __u8 __user *ubuf,
 		len = nr * CD_FRAMESIZE_RAW;
 
 		rq = blk_get_request(q, READ, GFP_KERNEL);
-		if (!rq) {
-			ret = -ENOMEM;
+		if (IS_ERR(rq)) {
+			ret = PTR_ERR(rq);
 			break;
 		}
 		blk_rq_set_block_pc(rq);
diff --git a/drivers/ide/ide-park.c b/drivers/ide/ide-park.c
index f41558a0bcd1..ca958604cda2 100644
--- a/drivers/ide/ide-park.c
+++ b/drivers/ide/ide-park.c
@@ -46,7 +46,7 @@ static void issue_park_cmd(ide_drive_t *drive, unsigned long timeout)
 	 * timeout has expired, so power management will be reenabled.
 	 */
 	rq = blk_get_request(q, READ, GFP_NOWAIT);
-	if (unlikely(!rq))
+	if (IS_ERR(rq))
 		goto out;
 
 	rq->cmd[0] = REQ_UNPARK_HEADS;
diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig
index 296619b7426c..3a820f61ce65 100644
--- a/drivers/scsi/Kconfig
+++ b/drivers/scsi/Kconfig
@@ -73,7 +73,6 @@ comment "SCSI support type (disk, tape, CD-ROM)"
 config BLK_DEV_SD
 	tristate "SCSI disk support"
 	depends on SCSI
-	select CRC_T10DIF if BLK_DEV_INTEGRITY
 	---help---
 	  If you want to use SCSI hard disks, Fibre Channel disks,
 	  Serial ATA (SATA) or Parallel ATA (PATA) hard disks,
diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 7bcf67eec921..e99507ed0e3c 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -115,7 +115,7 @@ static struct request *get_alua_req(struct scsi_device *sdev,
 
 	rq = blk_get_request(q, rw, GFP_NOIO);
 
-	if (!rq) {
+	if (IS_ERR(rq)) {
 		sdev_printk(KERN_INFO, sdev,
 			    "%s: blk_get_request failed\n", __func__);
 		return NULL;
diff --git a/drivers/scsi/device_handler/scsi_dh_emc.c b/drivers/scsi/device_handler/scsi_dh_emc.c
index 6f07f7fe3aa1..84765384c47c 100644
--- a/drivers/scsi/device_handler/scsi_dh_emc.c
+++ b/drivers/scsi/device_handler/scsi_dh_emc.c
@@ -275,7 +275,7 @@ static struct request *get_req(struct scsi_device *sdev, int cmd,
 
 	rq = blk_get_request(sdev->request_queue,
 			(cmd != INQUIRY) ? WRITE : READ, GFP_NOIO);
-	if (!rq) {
+	if (IS_ERR(rq)) {
 		sdev_printk(KERN_INFO, sdev, "get_req: blk_get_request failed");
 		return NULL;
 	}
diff --git a/drivers/scsi/device_handler/scsi_dh_hp_sw.c b/drivers/scsi/device_handler/scsi_dh_hp_sw.c
index e9d9fea9e272..4ee2759f5299 100644
--- a/drivers/scsi/device_handler/scsi_dh_hp_sw.c
+++ b/drivers/scsi/device_handler/scsi_dh_hp_sw.c
@@ -117,7 +117,7 @@ static int hp_sw_tur(struct scsi_device *sdev, struct hp_sw_dh_data *h)
 
 retry:
 	req = blk_get_request(sdev->request_queue, WRITE, GFP_NOIO);
-	if (!req)
+	if (IS_ERR(req))
 		return SCSI_DH_RES_TEMP_UNAVAIL;
 
 	blk_rq_set_block_pc(req);
@@ -247,7 +247,7 @@ static int hp_sw_start_stop(struct hp_sw_dh_data *h)
 	struct request *req;
 
 	req = blk_get_request(h->sdev->request_queue, WRITE, GFP_ATOMIC);
-	if (!req)
+	if (IS_ERR(req))
 		return SCSI_DH_RES_TEMP_UNAVAIL;
 
 	blk_rq_set_block_pc(req);
diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c b/drivers/scsi/device_handler/scsi_dh_rdac.c
index 826069db9848..1b5bc9293e37 100644
--- a/drivers/scsi/device_handler/scsi_dh_rdac.c
+++ b/drivers/scsi/device_handler/scsi_dh_rdac.c
@@ -274,7 +274,7 @@ static struct request *get_rdac_req(struct scsi_device *sdev,
 
 	rq = blk_get_request(q, rw, GFP_NOIO);
 
-	if (!rq) {
+	if (IS_ERR(rq)) {
 		sdev_printk(KERN_INFO, sdev,
 				"get_rdac_req: blk_get_request failed.\n");
 		return NULL;
diff --git a/drivers/scsi/osd/osd_initiator.c b/drivers/scsi/osd/osd_initiator.c
index 5f4cbf0c4759..fd19fd8468ac 100644
--- a/drivers/scsi/osd/osd_initiator.c
+++ b/drivers/scsi/osd/osd_initiator.c
@@ -1567,8 +1567,8 @@ static struct request *_make_request(struct request_queue *q, bool has_write,
 		struct request *req;
 
 		req = blk_get_request(q, has_write ? WRITE : READ, flags);
-		if (unlikely(!req))
-			return ERR_PTR(-ENOMEM);
+		if (IS_ERR(req))
+			return req;
 
 		blk_rq_set_block_pc(req);
 		return req;
diff --git a/drivers/scsi/osst.c b/drivers/scsi/osst.c
index 0727ea7cc387..dff37a250d79 100644
--- a/drivers/scsi/osst.c
+++ b/drivers/scsi/osst.c
@@ -362,7 +362,7 @@ static int osst_execute(struct osst_request *SRpnt, const unsigned char *cmd,
 	int write = (data_direction == DMA_TO_DEVICE);
 
 	req = blk_get_request(SRpnt->stp->device->request_queue, write, GFP_KERNEL);
-	if (!req)
+	if (IS_ERR(req))
 		return DRIVER_ERROR << 24;
 
 	blk_rq_set_block_pc(req);
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 6b20ef3fee54..9a6f8468225f 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -1961,6 +1961,8 @@ static void scsi_eh_lock_door(struct scsi_device *sdev)
 	 * request becomes available
 	 */
 	req = blk_get_request(sdev->request_queue, READ, GFP_KERNEL);
+	if (IS_ERR(req))
+		return;
 
 	blk_rq_set_block_pc(req);
 
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index db8c449282f9..9eff8a375132 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -221,7 +221,7 @@ int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
 	int ret = DRIVER_ERROR << 24;
 
 	req = blk_get_request(sdev->request_queue, write, __GFP_WAIT);
-	if (!req)
+	if (IS_ERR(req))
 		return ret;
 	blk_rq_set_block_pc(req);
 
@@ -715,7 +715,7 @@ static bool scsi_end_request(struct request *req, int error,
 
 	if (req->mq_ctx) {
 		/*
-		 * In the MQ case the command gets freed by __blk_mq_end_io,
+		 * In the MQ case the command gets freed by __blk_mq_end_request,
 		 * so we have to do all cleanup that depends on it earlier.
 		 *
 		 * We also can't kick the queues from irq context, so we
@@ -723,7 +723,7 @@ static bool scsi_end_request(struct request *req, int error,
 		 */
 		scsi_mq_uninit_cmd(cmd);
 
-		__blk_mq_end_io(req, error);
+		__blk_mq_end_request(req, error);
 
 		if (scsi_target(sdev)->single_lun ||
 		    !list_empty(&sdev->host->starved_list))
@@ -1847,6 +1847,8 @@ static int scsi_mq_prep_fn(struct request *req)
 		next_rq->special = bidi_sdb;
 	}
 
+	blk_mq_start_request(req);
+
 	return scsi_setup_cmnd(sdev, req);
 }
 
@@ -1856,7 +1858,8 @@ static void scsi_mq_done(struct scsi_cmnd *cmd)
 	blk_mq_complete_request(cmd->request);
 }
 
-static int scsi_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req)
+static int scsi_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req,
+		bool last)
 {
 	struct request_queue *q = req->q;
 	struct scsi_device *sdev = q->queuedata;
@@ -1880,11 +1883,14 @@ static int scsi_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req)
 	if (!scsi_host_queue_ready(q, shost, sdev))
 		goto out_dec_target_busy;
 
+
 	if (!(req->cmd_flags & REQ_DONTPREP)) {
 		ret = prep_to_mq(scsi_mq_prep_fn(req));
 		if (ret)
 			goto out_dec_host_busy;
 		req->cmd_flags |= REQ_DONTPREP;
+	} else {
+		blk_mq_start_request(req);
 	}
 
 	scsi_init_cmd_errh(cmd);
@@ -1931,6 +1937,14 @@ out:
 	return ret;
 }
 
+static enum blk_eh_timer_return scsi_timeout(struct request *req,
+		bool reserved)
+{
+	if (reserved)
+		return BLK_EH_RESET_TIMER;
+	return scsi_times_out(req);
+}
+
 static int scsi_init_request(void *data, struct request *rq,
 		unsigned int hctx_idx, unsigned int request_idx,
 		unsigned int numa_node)
@@ -2042,7 +2056,7 @@ static struct blk_mq_ops scsi_mq_ops = {
 	.map_queue	= blk_mq_map_queue,
 	.queue_rq	= scsi_queue_rq,
 	.complete	= scsi_softirq_done,
-	.timeout	= scsi_times_out,
+	.timeout	= scsi_timeout,
 	.init_request	= scsi_init_request,
 	.exit_request	= scsi_exit_request,
 };
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 0cb5c9f0c743..7ee86028a535 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -610,29 +610,44 @@ static void scsi_disk_put(struct scsi_disk *sdkp)
 	mutex_unlock(&sd_ref_mutex);
 }
 
-static void sd_prot_op(struct scsi_cmnd *scmd, unsigned int dif)
-{
-	unsigned int prot_op = SCSI_PROT_NORMAL;
-	unsigned int dix = scsi_prot_sg_count(scmd);
-
-	if (scmd->sc_data_direction == DMA_FROM_DEVICE) {
-		if (dif && dix)
-			prot_op = SCSI_PROT_READ_PASS;
-		else if (dif && !dix)
-			prot_op = SCSI_PROT_READ_STRIP;
-		else if (!dif && dix)
-			prot_op = SCSI_PROT_READ_INSERT;
-	} else {
-		if (dif && dix)
-			prot_op = SCSI_PROT_WRITE_PASS;
-		else if (dif && !dix)
-			prot_op = SCSI_PROT_WRITE_INSERT;
-		else if (!dif && dix)
-			prot_op = SCSI_PROT_WRITE_STRIP;
+
+
+static unsigned char sd_setup_protect_cmnd(struct scsi_cmnd *scmd,
+					   unsigned int dix, unsigned int dif)
+{
+	struct bio *bio = scmd->request->bio;
+	unsigned int prot_op = sd_prot_op(rq_data_dir(scmd->request), dix, dif);
+	unsigned int protect = 0;
+
+	if (dix) {				/* DIX Type 0, 1, 2, 3 */
+		if (bio_integrity_flagged(bio, BIP_IP_CHECKSUM))
+			scmd->prot_flags |= SCSI_PROT_IP_CHECKSUM;
+
+		if (bio_integrity_flagged(bio, BIP_CTRL_NOCHECK) == false)
+			scmd->prot_flags |= SCSI_PROT_GUARD_CHECK;
+	}
+
+	if (dif != SD_DIF_TYPE3_PROTECTION) {	/* DIX/DIF Type 0, 1, 2 */
+		scmd->prot_flags |= SCSI_PROT_REF_INCREMENT;
+
+		if (bio_integrity_flagged(bio, BIP_CTRL_NOCHECK) == false)
+			scmd->prot_flags |= SCSI_PROT_REF_CHECK;
+	}
+
+	if (dif) {				/* DIX/DIF Type 1, 2, 3 */
+		scmd->prot_flags |= SCSI_PROT_TRANSFER_PI;
+
+		if (bio_integrity_flagged(bio, BIP_DISK_NOCHECK))
+			protect = 3 << 5;	/* Disable target PI checking */
+		else
+			protect = 1 << 5;	/* Enable target PI checking */
 	}
 
 	scsi_set_prot_op(scmd, prot_op);
 	scsi_set_prot_type(scmd, dif);
+	scmd->prot_flags &= sd_prot_flag_mask(prot_op);
+
+	return protect;
 }
 
 static void sd_config_discard(struct scsi_disk *sdkp, unsigned int mode)
@@ -893,7 +908,8 @@ static int sd_setup_read_write_cmnd(struct scsi_cmnd *SCpnt)
 	sector_t block = blk_rq_pos(rq);
 	sector_t threshold;
 	unsigned int this_count = blk_rq_sectors(rq);
-	int ret, host_dif;
+	unsigned int dif, dix;
+	int ret;
 	unsigned char protect;
 
 	ret = scsi_init_io(SCpnt, GFP_ATOMIC);
@@ -995,7 +1011,7 @@ static int sd_setup_read_write_cmnd(struct scsi_cmnd *SCpnt)
 		SCpnt->cmnd[0] = WRITE_6;
 
 		if (blk_integrity_rq(rq))
-			sd_dif_prepare(rq, block, sdp->sector_size);
+			sd_dif_prepare(SCpnt);
 
 	} else if (rq_data_dir(rq) == READ) {
 		SCpnt->cmnd[0] = READ_6;
@@ -1010,14 +1026,15 @@ static int sd_setup_read_write_cmnd(struct scsi_cmnd *SCpnt)
 					"writing" : "reading", this_count,
 					blk_rq_sectors(rq)));
 
-	/* Set RDPROTECT/WRPROTECT if disk is formatted with DIF */
-	host_dif = scsi_host_dif_capable(sdp->host, sdkp->protection_type);
-	if (host_dif)
-		protect = 1 << 5;
+	dix = scsi_prot_sg_count(SCpnt);
+	dif = scsi_host_dif_capable(SCpnt->device->host, sdkp->protection_type);
+
+	if (dif || dix)
+		protect = sd_setup_protect_cmnd(SCpnt, dix, dif);
 	else
 		protect = 0;
 
-	if (host_dif == SD_DIF_TYPE2_PROTECTION) {
+	if (protect && sdkp->protection_type == SD_DIF_TYPE2_PROTECTION) {
 		SCpnt->cmnd = mempool_alloc(sd_cdb_pool, GFP_ATOMIC);
 
 		if (unlikely(SCpnt->cmnd == NULL)) {
@@ -1102,10 +1119,6 @@ static int sd_setup_read_write_cmnd(struct scsi_cmnd *SCpnt)
 	}
 	SCpnt->sdb.length = this_count * sdp->sector_size;
 
-	/* If DIF or DIX is enabled, tell HBA how to handle request */
-	if (host_dif || scsi_prot_sg_count(SCpnt))
-		sd_prot_op(SCpnt, host_dif);
-
 	/*
 	 * We shouldn't disconnect in the middle of a sector, so with a dumb
 	 * host adapter, it's safe to assume that we can at least transfer
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 4c3ab8377fd3..467377884b63 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -167,6 +167,68 @@ enum sd_dif_target_protection_types {
 };
 
 /*
+ * Look up the DIX operation based on whether the command is read or
+ * write and whether dix and dif are enabled.
+ */
+static inline unsigned int sd_prot_op(bool write, bool dix, bool dif)
+{
+	/* Lookup table: bit 2 (write), bit 1 (dix), bit 0 (dif) */
+	const unsigned int ops[] = {	/* wrt dix dif */
+		SCSI_PROT_NORMAL,	/*  0	0   0  */
+		SCSI_PROT_READ_STRIP,	/*  0	0   1  */
+		SCSI_PROT_READ_INSERT,	/*  0	1   0  */
+		SCSI_PROT_READ_PASS,	/*  0	1   1  */
+		SCSI_PROT_NORMAL,	/*  1	0   0  */
+		SCSI_PROT_WRITE_INSERT, /*  1	0   1  */
+		SCSI_PROT_WRITE_STRIP,	/*  1	1   0  */
+		SCSI_PROT_WRITE_PASS,	/*  1	1   1  */
+	};
+
+	return ops[write << 2 | dix << 1 | dif];
+}
+
+/*
+ * Returns a mask of the protection flags that are valid for a given DIX
+ * operation.
+ */
+static inline unsigned int sd_prot_flag_mask(unsigned int prot_op)
+{
+	const unsigned int flag_mask[] = {
+		[SCSI_PROT_NORMAL]		= 0,
+
+		[SCSI_PROT_READ_STRIP]		= SCSI_PROT_TRANSFER_PI |
+						  SCSI_PROT_GUARD_CHECK |
+						  SCSI_PROT_REF_CHECK |
+						  SCSI_PROT_REF_INCREMENT,
+
+		[SCSI_PROT_READ_INSERT]		= SCSI_PROT_REF_INCREMENT |
+						  SCSI_PROT_IP_CHECKSUM,
+
+		[SCSI_PROT_READ_PASS]		= SCSI_PROT_TRANSFER_PI |
+						  SCSI_PROT_GUARD_CHECK |
+						  SCSI_PROT_REF_CHECK |
+						  SCSI_PROT_REF_INCREMENT |
+						  SCSI_PROT_IP_CHECKSUM,
+
+		[SCSI_PROT_WRITE_INSERT]	= SCSI_PROT_TRANSFER_PI |
+						  SCSI_PROT_REF_INCREMENT,
+
+		[SCSI_PROT_WRITE_STRIP]		= SCSI_PROT_GUARD_CHECK |
+						  SCSI_PROT_REF_CHECK |
+						  SCSI_PROT_REF_INCREMENT |
+						  SCSI_PROT_IP_CHECKSUM,
+
+		[SCSI_PROT_WRITE_PASS]		= SCSI_PROT_TRANSFER_PI |
+						  SCSI_PROT_GUARD_CHECK |
+						  SCSI_PROT_REF_CHECK |
+						  SCSI_PROT_REF_INCREMENT |
+						  SCSI_PROT_IP_CHECKSUM,
+	};
+
+	return flag_mask[prot_op];
+}
+
+/*
  * Data Integrity Field tuple.
  */
 struct sd_dif_tuple {
@@ -178,7 +240,7 @@ struct sd_dif_tuple {
 #ifdef CONFIG_BLK_DEV_INTEGRITY
 
 extern void sd_dif_config_host(struct scsi_disk *);
-extern void sd_dif_prepare(struct request *rq, sector_t, unsigned int);
+extern void sd_dif_prepare(struct scsi_cmnd *scmd);
 extern void sd_dif_complete(struct scsi_cmnd *, unsigned int);
 
 #else /* CONFIG_BLK_DEV_INTEGRITY */
@@ -186,7 +248,7 @@ extern void sd_dif_complete(struct scsi_cmnd *, unsigned int);
 static inline void sd_dif_config_host(struct scsi_disk *disk)
 {
 }
-static inline int sd_dif_prepare(struct request *rq, sector_t s, unsigned int a)
+static inline int sd_dif_prepare(struct scsi_cmnd *scmd)
 {
 	return 0;
 }
diff --git a/drivers/scsi/sd_dif.c b/drivers/scsi/sd_dif.c
index a7a691d0af7d..14c7d42a11c2 100644
--- a/drivers/scsi/sd_dif.c
+++ b/drivers/scsi/sd_dif.c
@@ -21,7 +21,7 @@
  */
 
 #include <linux/blkdev.h>
-#include <linux/crc-t10dif.h>
+#include <linux/t10-pi.h>
 
 #include <scsi/scsi.h>
 #include <scsi/scsi_cmnd.h>
@@ -33,268 +33,8 @@
 #include <scsi/scsi_ioctl.h>
 #include <scsi/scsicam.h>
 
-#include <net/checksum.h>
-
 #include "sd.h"
 
-typedef __u16 (csum_fn) (void *, unsigned int);
-
-static __u16 sd_dif_crc_fn(void *data, unsigned int len)
-{
-	return cpu_to_be16(crc_t10dif(data, len));
-}
-
-static __u16 sd_dif_ip_fn(void *data, unsigned int len)
-{
-	return ip_compute_csum(data, len);
-}
-
-/*
- * Type 1 and Type 2 protection use the same format: 16 bit guard tag,
- * 16 bit app tag, 32 bit reference tag.
- */
-static void sd_dif_type1_generate(struct blk_integrity_exchg *bix, csum_fn *fn)
-{
-	void *buf = bix->data_buf;
-	struct sd_dif_tuple *sdt = bix->prot_buf;
-	sector_t sector = bix->sector;
-	unsigned int i;
-
-	for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
-		sdt->guard_tag = fn(buf, bix->sector_size);
-		sdt->ref_tag = cpu_to_be32(sector & 0xffffffff);
-		sdt->app_tag = 0;
-
-		buf += bix->sector_size;
-		sector++;
-	}
-}
-
-static void sd_dif_type1_generate_crc(struct blk_integrity_exchg *bix)
-{
-	sd_dif_type1_generate(bix, sd_dif_crc_fn);
-}
-
-static void sd_dif_type1_generate_ip(struct blk_integrity_exchg *bix)
-{
-	sd_dif_type1_generate(bix, sd_dif_ip_fn);
-}
-
-static int sd_dif_type1_verify(struct blk_integrity_exchg *bix, csum_fn *fn)
-{
-	void *buf = bix->data_buf;
-	struct sd_dif_tuple *sdt = bix->prot_buf;
-	sector_t sector = bix->sector;
-	unsigned int i;
-	__u16 csum;
-
-	for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
-		/* Unwritten sectors */
-		if (sdt->app_tag == 0xffff)
-			return 0;
-
-		if (be32_to_cpu(sdt->ref_tag) != (sector & 0xffffffff)) {
-			printk(KERN_ERR
-			       "%s: ref tag error on sector %lu (rcvd %u)\n",
-			       bix->disk_name, (unsigned long)sector,
-			       be32_to_cpu(sdt->ref_tag));
-			return -EIO;
-		}
-
-		csum = fn(buf, bix->sector_size);
-
-		if (sdt->guard_tag != csum) {
-			printk(KERN_ERR "%s: guard tag error on sector %lu " \
-			       "(rcvd %04x, data %04x)\n", bix->disk_name,
-			       (unsigned long)sector,
-			       be16_to_cpu(sdt->guard_tag), be16_to_cpu(csum));
-			return -EIO;
-		}
-
-		buf += bix->sector_size;
-		sector++;
-	}
-
-	return 0;
-}
-
-static int sd_dif_type1_verify_crc(struct blk_integrity_exchg *bix)
-{
-	return sd_dif_type1_verify(bix, sd_dif_crc_fn);
-}
-
-static int sd_dif_type1_verify_ip(struct blk_integrity_exchg *bix)
-{
-	return sd_dif_type1_verify(bix, sd_dif_ip_fn);
-}
-
-/*
- * Functions for interleaving and deinterleaving application tags
- */
-static void sd_dif_type1_set_tag(void *prot, void *tag_buf, unsigned int sectors)
-{
-	struct sd_dif_tuple *sdt = prot;
-	u8 *tag = tag_buf;
-	unsigned int i, j;
-
-	for (i = 0, j = 0 ; i < sectors ; i++, j += 2, sdt++) {
-		sdt->app_tag = tag[j] << 8 | tag[j+1];
-		BUG_ON(sdt->app_tag == 0xffff);
-	}
-}
-
-static void sd_dif_type1_get_tag(void *prot, void *tag_buf, unsigned int sectors)
-{
-	struct sd_dif_tuple *sdt = prot;
-	u8 *tag = tag_buf;
-	unsigned int i, j;
-
-	for (i = 0, j = 0 ; i < sectors ; i++, j += 2, sdt++) {
-		tag[j] = (sdt->app_tag & 0xff00) >> 8;
-		tag[j+1] = sdt->app_tag & 0xff;
-	}
-}
-
-static struct blk_integrity dif_type1_integrity_crc = {
-	.name			= "T10-DIF-TYPE1-CRC",
-	.generate_fn		= sd_dif_type1_generate_crc,
-	.verify_fn		= sd_dif_type1_verify_crc,
-	.get_tag_fn		= sd_dif_type1_get_tag,
-	.set_tag_fn		= sd_dif_type1_set_tag,
-	.tuple_size		= sizeof(struct sd_dif_tuple),
-	.tag_size		= 0,
-};
-
-static struct blk_integrity dif_type1_integrity_ip = {
-	.name			= "T10-DIF-TYPE1-IP",
-	.generate_fn		= sd_dif_type1_generate_ip,
-	.verify_fn		= sd_dif_type1_verify_ip,
-	.get_tag_fn		= sd_dif_type1_get_tag,
-	.set_tag_fn		= sd_dif_type1_set_tag,
-	.tuple_size		= sizeof(struct sd_dif_tuple),
-	.tag_size		= 0,
-};
-
-
-/*
- * Type 3 protection has a 16-bit guard tag and 16 + 32 bits of opaque
- * tag space.
- */
-static void sd_dif_type3_generate(struct blk_integrity_exchg *bix, csum_fn *fn)
-{
-	void *buf = bix->data_buf;
-	struct sd_dif_tuple *sdt = bix->prot_buf;
-	unsigned int i;
-
-	for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
-		sdt->guard_tag = fn(buf, bix->sector_size);
-		sdt->ref_tag = 0;
-		sdt->app_tag = 0;
-
-		buf += bix->sector_size;
-	}
-}
-
-static void sd_dif_type3_generate_crc(struct blk_integrity_exchg *bix)
-{
-	sd_dif_type3_generate(bix, sd_dif_crc_fn);
-}
-
-static void sd_dif_type3_generate_ip(struct blk_integrity_exchg *bix)
-{
-	sd_dif_type3_generate(bix, sd_dif_ip_fn);
-}
-
-static int sd_dif_type3_verify(struct blk_integrity_exchg *bix, csum_fn *fn)
-{
-	void *buf = bix->data_buf;
-	struct sd_dif_tuple *sdt = bix->prot_buf;
-	sector_t sector = bix->sector;
-	unsigned int i;
-	__u16 csum;
-
-	for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
-		/* Unwritten sectors */
-		if (sdt->app_tag == 0xffff && sdt->ref_tag == 0xffffffff)
-			return 0;
-
-		csum = fn(buf, bix->sector_size);
-
-		if (sdt->guard_tag != csum) {
-			printk(KERN_ERR "%s: guard tag error on sector %lu " \
-			       "(rcvd %04x, data %04x)\n", bix->disk_name,
-			       (unsigned long)sector,
-			       be16_to_cpu(sdt->guard_tag), be16_to_cpu(csum));
-			return -EIO;
-		}
-
-		buf += bix->sector_size;
-		sector++;
-	}
-
-	return 0;
-}
-
-static int sd_dif_type3_verify_crc(struct blk_integrity_exchg *bix)
-{
-	return sd_dif_type3_verify(bix, sd_dif_crc_fn);
-}
-
-static int sd_dif_type3_verify_ip(struct blk_integrity_exchg *bix)
-{
-	return sd_dif_type3_verify(bix, sd_dif_ip_fn);
-}
-
-static void sd_dif_type3_set_tag(void *prot, void *tag_buf, unsigned int sectors)
-{
-	struct sd_dif_tuple *sdt = prot;
-	u8 *tag = tag_buf;
-	unsigned int i, j;
-
-	for (i = 0, j = 0 ; i < sectors ; i++, j += 6, sdt++) {
-		sdt->app_tag = tag[j] << 8 | tag[j+1];
-		sdt->ref_tag = tag[j+2] << 24 | tag[j+3] << 16 |
-			tag[j+4] << 8 | tag[j+5];
-	}
-}
-
-static void sd_dif_type3_get_tag(void *prot, void *tag_buf, unsigned int sectors)
-{
-	struct sd_dif_tuple *sdt = prot;
-	u8 *tag = tag_buf;
-	unsigned int i, j;
-
-	for (i = 0, j = 0 ; i < sectors ; i++, j += 2, sdt++) {
-		tag[j] = (sdt->app_tag & 0xff00) >> 8;
-		tag[j+1] = sdt->app_tag & 0xff;
-		tag[j+2] = (sdt->ref_tag & 0xff000000) >> 24;
-		tag[j+3] = (sdt->ref_tag & 0xff0000) >> 16;
-		tag[j+4] = (sdt->ref_tag & 0xff00) >> 8;
-		tag[j+5] = sdt->ref_tag & 0xff;
-		BUG_ON(sdt->app_tag == 0xffff || sdt->ref_tag == 0xffffffff);
-	}
-}
-
-static struct blk_integrity dif_type3_integrity_crc = {
-	.name			= "T10-DIF-TYPE3-CRC",
-	.generate_fn		= sd_dif_type3_generate_crc,
-	.verify_fn		= sd_dif_type3_verify_crc,
-	.get_tag_fn		= sd_dif_type3_get_tag,
-	.set_tag_fn		= sd_dif_type3_set_tag,
-	.tuple_size		= sizeof(struct sd_dif_tuple),
-	.tag_size		= 0,
-};
-
-static struct blk_integrity dif_type3_integrity_ip = {
-	.name			= "T10-DIF-TYPE3-IP",
-	.generate_fn		= sd_dif_type3_generate_ip,
-	.verify_fn		= sd_dif_type3_verify_ip,
-	.get_tag_fn		= sd_dif_type3_get_tag,
-	.set_tag_fn		= sd_dif_type3_set_tag,
-	.tuple_size		= sizeof(struct sd_dif_tuple),
-	.tag_size		= 0,
-};
-
 /*
  * Configure exchange of protection information between OS and HBA.
  */
@@ -316,22 +56,30 @@ void sd_dif_config_host(struct scsi_disk *sdkp)
 		return;
 
 	/* Enable DMA of protection information */
-	if (scsi_host_get_guard(sdkp->device->host) & SHOST_DIX_GUARD_IP)
+	if (scsi_host_get_guard(sdkp->device->host) & SHOST_DIX_GUARD_IP) {
 		if (type == SD_DIF_TYPE3_PROTECTION)
-			blk_integrity_register(disk, &dif_type3_integrity_ip);
+			blk_integrity_register(disk, &t10_pi_type3_ip);
 		else
-			blk_integrity_register(disk, &dif_type1_integrity_ip);
-	else
+			blk_integrity_register(disk, &t10_pi_type1_ip);
+
+		disk->integrity->flags |= BLK_INTEGRITY_IP_CHECKSUM;
+	} else
 		if (type == SD_DIF_TYPE3_PROTECTION)
-			blk_integrity_register(disk, &dif_type3_integrity_crc);
+			blk_integrity_register(disk, &t10_pi_type3_crc);
 		else
-			blk_integrity_register(disk, &dif_type1_integrity_crc);
+			blk_integrity_register(disk, &t10_pi_type1_crc);
 
 	sd_printk(KERN_NOTICE, sdkp,
 		  "Enabling DIX %s protection\n", disk->integrity->name);
 
 	/* Signal to block layer that we support sector tagging */
-	if (dif && type && sdkp->ATO) {
+	if (dif && type) {
+
+		disk->integrity->flags |= BLK_INTEGRITY_DEVICE_CAPABLE;
+
+		if (!sdkp)
+			return;
+
 		if (type == SD_DIF_TYPE3_PROTECTION)
 			disk->integrity->tag_size = sizeof(u16) + sizeof(u32);
 		else
@@ -358,50 +106,49 @@ void sd_dif_config_host(struct scsi_disk *sdkp)
  *
  * Type 3 does not have a reference tag so no remapping is required.
  */
-void sd_dif_prepare(struct request *rq, sector_t hw_sector,
-		    unsigned int sector_sz)
+void sd_dif_prepare(struct scsi_cmnd *scmd)
 {
-	const int tuple_sz = sizeof(struct sd_dif_tuple);
+	const int tuple_sz = sizeof(struct t10_pi_tuple);
 	struct bio *bio;
 	struct scsi_disk *sdkp;
-	struct sd_dif_tuple *sdt;
+	struct t10_pi_tuple *pi;
 	u32 phys, virt;
 
-	sdkp = rq->bio->bi_bdev->bd_disk->private_data;
+	sdkp = scsi_disk(scmd->request->rq_disk);
 
 	if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION)
 		return;
 
-	phys = hw_sector & 0xffffffff;
+	phys = scsi_prot_ref_tag(scmd);
 
-	__rq_for_each_bio(bio, rq) {
+	__rq_for_each_bio(bio, scmd->request) {
+		struct bio_integrity_payload *bip = bio_integrity(bio);
 		struct bio_vec iv;
 		struct bvec_iter iter;
 		unsigned int j;
 
 		/* Already remapped? */
-		if (bio_flagged(bio, BIO_MAPPED_INTEGRITY))
+		if (bip->bip_flags & BIP_MAPPED_INTEGRITY)
 			break;
 
-		virt = bio->bi_integrity->bip_iter.bi_sector & 0xffffffff;
+		virt = bip_get_seed(bip) & 0xffffffff;
 
-		bip_for_each_vec(iv, bio->bi_integrity, iter) {
-			sdt = kmap_atomic(iv.bv_page)
-				+ iv.bv_offset;
+		bip_for_each_vec(iv, bip, iter) {
+			pi = kmap_atomic(iv.bv_page) + iv.bv_offset;
 
-			for (j = 0; j < iv.bv_len; j += tuple_sz, sdt++) {
+			for (j = 0; j < iv.bv_len; j += tuple_sz, pi++) {
 
-				if (be32_to_cpu(sdt->ref_tag) == virt)
-					sdt->ref_tag = cpu_to_be32(phys);
+				if (be32_to_cpu(pi->ref_tag) == virt)
+					pi->ref_tag = cpu_to_be32(phys);
 
 				virt++;
 				phys++;
 			}
 
-			kunmap_atomic(sdt);
+			kunmap_atomic(pi);
 		}
 
-		bio->bi_flags |= (1 << BIO_MAPPED_INTEGRITY);
+		bip->bip_flags |= BIP_MAPPED_INTEGRITY;
 	}
 }
 
@@ -411,11 +158,11 @@ void sd_dif_prepare(struct request *rq, sector_t hw_sector,
  */
 void sd_dif_complete(struct scsi_cmnd *scmd, unsigned int good_bytes)
 {
-	const int tuple_sz = sizeof(struct sd_dif_tuple);
+	const int tuple_sz = sizeof(struct t10_pi_tuple);
 	struct scsi_disk *sdkp;
 	struct bio *bio;
-	struct sd_dif_tuple *sdt;
-	unsigned int j, sectors, sector_sz;
+	struct t10_pi_tuple *pi;
+	unsigned int j, intervals;
 	u32 phys, virt;
 
 	sdkp = scsi_disk(scmd->request->rq_disk);
@@ -423,39 +170,35 @@ void sd_dif_complete(struct scsi_cmnd *scmd, unsigned int good_bytes)
 	if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION || good_bytes == 0)
 		return;
 
-	sector_sz = scmd->device->sector_size;
-	sectors = good_bytes / sector_sz;
-
-	phys = blk_rq_pos(scmd->request) & 0xffffffff;
-	if (sector_sz == 4096)
-		phys >>= 3;
+	intervals = good_bytes / scsi_prot_interval(scmd);
+	phys = scsi_prot_ref_tag(scmd);
 
 	__rq_for_each_bio(bio, scmd->request) {
+		struct bio_integrity_payload *bip = bio_integrity(bio);
 		struct bio_vec iv;
 		struct bvec_iter iter;
 
-		virt = bio->bi_integrity->bip_iter.bi_sector & 0xffffffff;
+		virt = bip_get_seed(bip) & 0xffffffff;
 
-		bip_for_each_vec(iv, bio->bi_integrity, iter) {
-			sdt = kmap_atomic(iv.bv_page)
-				+ iv.bv_offset;
+		bip_for_each_vec(iv, bip, iter) {
+			pi = kmap_atomic(iv.bv_page) + iv.bv_offset;
 
-			for (j = 0; j < iv.bv_len; j += tuple_sz, sdt++) {
+			for (j = 0; j < iv.bv_len; j += tuple_sz, pi++) {
 
-				if (sectors == 0) {
-					kunmap_atomic(sdt);
+				if (intervals == 0) {
+					kunmap_atomic(pi);
 					return;
 				}
 
-				if (be32_to_cpu(sdt->ref_tag) == phys)
-					sdt->ref_tag = cpu_to_be32(virt);
+				if (be32_to_cpu(pi->ref_tag) == phys)
+					pi->ref_tag = cpu_to_be32(virt);
 
 				virt++;
 				phys++;
-				sectors--;
+				intervals--;
 			}
 
-			kunmap_atomic(sdt);
+			kunmap_atomic(pi);
 		}
 	}
 }
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 01cf88888797..60354449d9ed 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -1711,9 +1711,9 @@ sg_start_req(Sg_request *srp, unsigned char *cmd)
 	}
 
 	rq = blk_get_request(q, rw, GFP_ATOMIC);
-	if (!rq) {
+	if (IS_ERR(rq)) {
 		kfree(long_cmdp);
-		return -ENOMEM;
+		return PTR_ERR(rq);
 	}
 
 	blk_rq_set_block_pc(rq);
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index d3fd6e8fb378..4daa372ed381 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -490,7 +490,7 @@ static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd,
 
 	req = blk_get_request(SRpnt->stp->device->request_queue, write,
 			      GFP_KERNEL);
-	if (!req)
+	if (IS_ERR(req))
 		return DRIVER_ERROR << 24;
 
 	blk_rq_set_block_pc(req);
diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c
index 943b1dbe859a..70d9f6dabba0 100644
--- a/drivers/target/target_core_pscsi.c
+++ b/drivers/target/target_core_pscsi.c
@@ -1050,7 +1050,7 @@ pscsi_execute_cmd(struct se_cmd *cmd)
 		req = blk_get_request(pdv->pdv_sd->request_queue,
 				(data_direction == DMA_TO_DEVICE),
 				GFP_KERNEL);
-		if (!req) {
+		if (IS_ERR(req)) {
 			pr_err("PSCSI: blk_get_request() failed\n");
 			ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 			goto fail;