dedicated error codes for the block layer

dedicated error codes for the block layer

[Christoph Hellwig]

This series introduces a new blk_status_t error code type for the block
layer so that we can have tigher control and explicit semantics for
block layer errors.

All but the last three patches are cleanups that lead to the new type.

The series it mostly limited to the block layer and drivers, and touching
file systems a little bit.  The only major exception is btrfs, which
does funny things with bios and thus sees a larger amount of propagation
of the new blk_status_t.

[PATCH 01/15] nvme-lightnvm: use blk_execute_rq in nvme_nvm_submit_user_cmd

[Christoph Hellwig]

Instead of reinventing it poorly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Javier González <javier@cnexlabs.com>
---
 drivers/nvme/host/lightnvm.c | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/drivers/nvme/host/lightnvm.c b/drivers/nvme/host/lightnvm.c
index f5df78ed1e10..f3885b5e56bd 100644
--- a/drivers/nvme/host/lightnvm.c
+++ b/drivers/nvme/host/lightnvm.c
@@ -571,13 +571,6 @@ static struct nvm_dev_ops nvme_nvm_dev_ops = {
 	.max_phys_sect		= 64,
 };
 
-static void nvme_nvm_end_user_vio(struct request *rq, int error)
-{
-	struct completion *waiting = rq->end_io_data;
-
-	complete(waiting);
-}
-
 static int nvme_nvm_submit_user_cmd(struct request_queue *q,
 				struct nvme_ns *ns,
 				struct nvme_nvm_command *vcmd,
@@ -608,7 +601,6 @@ static int nvme_nvm_submit_user_cmd(struct request_queue *q,
 	rq->timeout = timeout ? timeout : ADMIN_TIMEOUT;
 
 	rq->cmd_flags &= ~REQ_FAILFAST_DRIVER;
-	rq->end_io_data = &wait;
 
 	if (ppa_buf && ppa_len) {
 		ppa_list = dma_pool_alloc(dev->dma_pool, GFP_KERNEL, &ppa_dma);
@@ -662,9 +654,7 @@ static int nvme_nvm_submit_user_cmd(struct request_queue *q,
 	}
 
 submit:
-	blk_execute_rq_nowait(q, NULL, rq, 0, nvme_nvm_end_user_vio);
-
-	wait_for_completion_io(&wait);
+	blk_execute_rq(q, NULL, rq, 0);
 
 	if (nvme_req(rq)->flags & NVME_REQ_CANCELLED)
 		ret = -EINTR;
-- 
2.11.0

Re: [PATCH 01/15] nvme-lightnvm: use blk_execute_rq in nvme_nvm_submit_user_cmd

[Bart Van Assche]

On Thu, 2017-05-18 at 15:17 +0200, Christoph Hellwig wrote:
> Instead of reinventing it poorly.

Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com>

[PATCH 02/15] scsi/osd: don't save block errors into req_results

[Christoph Hellwig]

We will only have sense data if the command exectured and got a SCSI
result, so this is pointless.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/osd/osd_initiator.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/osd/osd_initiator.c b/drivers/scsi/osd/osd_initiator.c
index 8a1b94816419..14785177ce7b 100644
--- a/drivers/scsi/osd/osd_initiator.c
+++ b/drivers/scsi/osd/osd_initiator.c
@@ -477,7 +477,7 @@ static void _set_error_resid(struct osd_request *or, struct request *req,
 			     int error)
 {
 	or->async_error = error;
-	or->req_errors = scsi_req(req)->result ? : error;
+	or->req_errors = scsi_req(req)->result;
 	or->sense_len = scsi_req(req)->sense_len;
 	if (or->sense_len)
 		memcpy(or->sense, scsi_req(req)->sense, or->sense_len);
-- 
2.11.0

Re: [PATCH 02/15] scsi/osd: don't save block errors into req_results

[Bart Van Assche]

On Thu, 2017-05-18 at 15:17 +0200, Christoph Hellwig wrote:
> We will only have sense data if the command exectured and got a SCSI
> result, so this is pointless.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  drivers/scsi/osd/osd_initiator.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/osd/osd_initiator.c b/drivers/scsi/osd/osd_initiator.c
> index 8a1b94816419..14785177ce7b 100644
> --- a/drivers/scsi/osd/osd_initiator.c
> +++ b/drivers/scsi/osd/osd_initiator.c
> @@ -477,7 +477,7 @@ static void _set_error_resid(struct osd_request *or, struct request *req,
>  			     int error)
>  {
>  	or->async_error = error;
> -	or->req_errors = scsi_req(req)->result ? : error;
> +	or->req_errors = scsi_req(req)->result;
>  	or->sense_len = scsi_req(req)->sense_len;
>  	if (or->sense_len)
>  		memcpy(or->sense, scsi_req(req)->sense, or->sense_len);

Hello Christoph,

Are you sure that that code is not necessary? From osd_initiator.c:

static void _put_request(struct request *rq)
{
	/*
	 * If osd_finalize_request() was called but the request was not
	 * executed through the block layer, then we must release BIOs.
	 * TODO: Keep error code in or->async_error. Need to audit all
	 *       code paths.
	 */
	if (unlikely(rq->bio))
		blk_end_request(rq, -ENOMEM, blk_rq_bytes(rq));
	else
		blk_put_request(rq);
}

Bart.

Re: [PATCH 02/15] scsi/osd: don't save block errors into req_results

[hch]

On Wed, May 24, 2017 at 04:04:40PM +0000, Bart Van Assche wrote:
> Are you sure that that code is not necessary? From osd_initiator.c:
> 
> static void _put_request(struct request *rq)
> {
> 	/*
> 	 * If osd_finalize_request() was called but the request was not
> 	 * executed through the block layer, then we must release BIOs.
> 	 * TODO: Keep error code in or->async_error. Need to audit all
> 	 *       code paths.
> 	 */
> 	if (unlikely(rq->bio))
> 		blk_end_request(rq, -ENOMEM, blk_rq_bytes(rq));
> 	else
> 		blk_put_request(rq);
> }

Which isn't using it at all.  It has a ten year old comment to pass
on some error, but even then ORing two different error types together
would no be very helpful.

> 
> Bart.---end quoted text---

[PATCH 03/15] gfs2: remove the unused sd_log_error field

[Christoph Hellwig]

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/gfs2/incore.h | 1 -
 fs/gfs2/lops.c   | 4 +---
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index b7cf65d13561..aa3d44527fa2 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -815,7 +815,6 @@ struct gfs2_sbd {
 	atomic_t sd_log_in_flight;
 	struct bio *sd_log_bio;
 	wait_queue_head_t sd_log_flush_wait;
-	int sd_log_error;
 
 	atomic_t sd_reserving_log;
 	wait_queue_head_t sd_reserving_log_wait;
diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c
index b1f9144b42c7..13ebf15a4db0 100644
--- a/fs/gfs2/lops.c
+++ b/fs/gfs2/lops.c
@@ -209,10 +209,8 @@ static void gfs2_end_log_write(struct bio *bio)
 	struct page *page;
 	int i;
 
-	if (bio->bi_error) {
-		sdp->sd_log_error = bio->bi_error;
+	if (bio->bi_error)
 		fs_err(sdp, "Error %d writing to log\n", bio->bi_error);
-	}
 
 	bio_for_each_segment_all(bvec, bio, i) {
 		page = bvec->bv_page;
-- 
2.11.0

Re: [PATCH 03/15] gfs2: remove the unused sd_log_error field

[Bart Van Assche]

On Thu, 2017-05-18 at 15:18 +0200, Christoph Hellwig wrote:
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com>

[PATCH 04/15] dm: fix REQ_RAHEAD handling

[Christoph Hellwig]

A few (but not all) dm targets use a special EWOULDBLOCK error code for
failing REQ_RAHEAD requests that fail due to a lack of available resources.
But no one else knows about this magic code, and lower level drivers also
don't generate it when failing read-ahead requests for similar reasons.

So remove this special casing and ignore all additional error handling for
REQ_RAHEAD - if this was a real underlying error we'd get a normal read
once the real read comes in.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/md/dm-raid1.c  | 4 ++--
 drivers/md/dm-stripe.c | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index a95cbb80fb34..5e30b08b91d9 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -1214,7 +1214,7 @@ static int mirror_map(struct dm_target *ti, struct bio *bio)
 	 */
 	if (!r || (r == -EWOULDBLOCK)) {
 		if (bio->bi_opf & REQ_RAHEAD)
-			return -EWOULDBLOCK;
+			return -EIO;
 
 		queue_bio(ms, bio, rw);
 		return DM_MAPIO_SUBMITTED;
@@ -1258,7 +1258,7 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio, int error)
 	if (error == -EOPNOTSUPP)
 		return error;
 
-	if ((error == -EWOULDBLOCK) && (bio->bi_opf & REQ_RAHEAD))
+	if (bio->bi_opf & REQ_RAHEAD)
 		return error;
 
 	if (unlikely(error)) {
diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
index 75152482f3ad..780e95889a7c 100644
--- a/drivers/md/dm-stripe.c
+++ b/drivers/md/dm-stripe.c
@@ -384,7 +384,7 @@ static int stripe_end_io(struct dm_target *ti, struct bio *bio, int error)
 	if (!error)
 		return 0; /* I/O complete */
 
-	if ((error == -EWOULDBLOCK) && (bio->bi_opf & REQ_RAHEAD))
+	if (bio->bi_opf & REQ_RAHEAD)
 		return error;
 
 	if (error == -EOPNOTSUPP)
-- 
2.11.0

Re: [PATCH 04/15] dm: fix REQ_RAHEAD handling

[Bart Van Assche]

On Thu, 2017-05-18 at 15:18 +0200, Christoph Hellwig wrote:
> A few (but not all) dm targets use a special EWOULDBLOCK error code for
> failing REQ_RAHEAD requests that fail due to a lack of available resources.
> But no one else knows about this magic code, and lower level drivers also
> don't generate it when failing read-ahead requests for similar reasons.
> 
> So remove this special casing and ignore all additional error handling for
> REQ_RAHEAD - if this was a real underlying error we'd get a normal read
> once the real read comes in.

Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com>

[PATCH 05/15] fs: remove the unused error argument to dio_end_io()

[Christoph Hellwig]

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/btrfs/inode.c   | 6 +++---
 fs/direct-io.c     | 3 +--
 include/linux/fs.h | 2 +-
 3 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 17cbe9306faf..758b2666885e 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -8244,7 +8244,7 @@ static void btrfs_endio_direct_read(struct bio *bio)
 	kfree(dip);
 
 	dio_bio->bi_error = bio->bi_error;
-	dio_end_io(dio_bio, bio->bi_error);
+	dio_end_io(dio_bio);
 
 	if (io_bio->end_io)
 		io_bio->end_io(io_bio, err);
@@ -8304,7 +8304,7 @@ static void btrfs_endio_direct_write(struct bio *bio)
 	kfree(dip);
 
 	dio_bio->bi_error = bio->bi_error;
-	dio_end_io(dio_bio, bio->bi_error);
+	dio_end_io(dio_bio);
 	bio_put(bio);
 }
 
@@ -8673,7 +8673,7 @@ static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode,
 		 * Releases and cleans up our dio_bio, no need to bio_put()
 		 * nor bio_endio()/bio_io_error() against dio_bio.
 		 */
-		dio_end_io(dio_bio, ret);
+		dio_end_io(dio_bio);
 	}
 	if (io_bio)
 		bio_put(io_bio);
diff --git a/fs/direct-io.c b/fs/direct-io.c
index a04ebea77de8..04247a6c3f73 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -348,13 +348,12 @@ static void dio_bio_end_io(struct bio *bio)
 /**
  * dio_end_io - handle the end io action for the given bio
  * @bio: The direct io bio thats being completed
- * @error: Error if there was one
  *
  * This is meant to be called by any filesystem that uses their own dio_submit_t
  * so that the DIO specific endio actions are dealt with after the filesystem
  * has done it's completion work.
  */
-void dio_end_io(struct bio *bio, int error)
+void dio_end_io(struct bio *bio)
 {
 	struct dio *dio = bio->bi_private;
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 803e5a9b2654..4388ab58843d 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2843,7 +2843,7 @@ enum {
 	DIO_SKIP_DIO_COUNT = 0x08,
 };
 
-void dio_end_io(struct bio *bio, int error);
+void dio_end_io(struct bio *bio);
 
 ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
 			     struct block_device *bdev, struct iov_iter *iter,
-- 
2.11.0

Re: [PATCH 05/15] fs: remove the unused error argument to dio_end_io()

[Bart Van Assche]

On Thu, 2017-05-18 at 15:18 +0200, Christoph Hellwig wrote:
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com>

[PATCH 06/15] fs: simplify dio_bio_complete

[Christoph Hellwig]

Only read bio->bi_error once in the common path.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/direct-io.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/direct-io.c b/fs/direct-io.c
index 04247a6c3f73..bb711e4b86c2 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -477,13 +477,12 @@ static int dio_bio_complete(struct dio *dio, struct bio *bio)
 {
 	struct bio_vec *bvec;
 	unsigned i;
-	int err;
+	int err = bio->bi_error;
 
-	if (bio->bi_error)
+	if (err)
 		dio->io_error = -EIO;
 
 	if (dio->is_async && dio->op == REQ_OP_READ && dio->should_dirty) {
-		err = bio->bi_error;
 		bio_check_pages_dirty(bio);	/* transfers ownership */
 	} else {
 		bio_for_each_segment_all(bvec, bio, i) {
@@ -494,7 +493,6 @@ static int dio_bio_complete(struct dio *dio, struct bio *bio)
 				set_page_dirty_lock(page);
 			put_page(page);
 		}
-		err = bio->bi_error;
 		bio_put(bio);
 	}
 	return err;
-- 
2.11.0

Re: [PATCH 06/15] fs: simplify dio_bio_complete

[Bart Van Assche]

On Thu, 2017-05-18 at 15:18 +0200, Christoph Hellwig wrote:
> Only read bio->bi_error once in the common path.

Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com>

[PATCH 07/15] block_dev: propagate bio_iov_iter_get_pages error in __blkdev_direct_IO

[Christoph Hellwig]

Once we move the block layer to its own status code we'll still want to
propagate the bio_iov_iter_get_pages, so restructure __blkdev_direct_IO
to take ret into account when returning the errno.
---
 fs/block_dev.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 519599dddd36..c1dc393ad6b9 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -334,7 +334,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
 	bool is_read = (iov_iter_rw(iter) == READ), is_sync;
 	loff_t pos = iocb->ki_pos;
 	blk_qc_t qc = BLK_QC_T_NONE;
-	int ret;
+	int ret = 0;
 
 	if ((pos | iov_iter_alignment(iter)) &
 	    (bdev_logical_block_size(bdev) - 1))
@@ -363,7 +363,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
 
 		ret = bio_iov_iter_get_pages(bio, iter);
 		if (unlikely(ret)) {
-			bio->bi_error = ret;
+			bio->bi_error = -EIO;
 			bio_endio(bio);
 			break;
 		}
@@ -412,7 +412,8 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
 	}
 	__set_current_state(TASK_RUNNING);
 
-	ret = dio->bio.bi_error;
+	if (!ret)
+		ret = dio->bio.bi_error;
 	if (likely(!ret))
 		ret = dio->size;
 
-- 
2.11.0

[PATCH 08/15] dm mpath: merge do_end_io_bio into multipath_end_io_bio

[Christoph Hellwig]

This simplifies the code and especially the error passing a bit and
will help with the next patch.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/md/dm-mpath.c | 42 ++++++++++++++++--------------------------
 1 file changed, 16 insertions(+), 26 deletions(-)

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 3df056b73b66..b1cb0273b081 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -1510,24 +1510,26 @@ static int multipath_end_io(struct dm_target *ti, struct request *clone,
 	return r;
 }
 
-static int do_end_io_bio(struct multipath *m, struct bio *clone,
-			 int error, struct dm_mpath_io *mpio)
+static int multipath_end_io_bio(struct dm_target *ti, struct bio *clone, int error)
 {
+	struct multipath *m = ti->private;
+	struct dm_mpath_io *mpio = get_mpio_from_bio(clone);
+	struct pgpath *pgpath = mpio->pgpath;
 	unsigned long flags;
 
-	if (!error)
-		return 0;	/* I/O complete */
+	BUG_ON(!mpio);
 
-	if (noretry_error(error))
-		return error;
+	if (!error || noretry_error(error))
+		goto done;
 
-	if (mpio->pgpath)
-		fail_path(mpio->pgpath);
+	if (pgpath)
+		fail_path(pgpath);
 
 	if (atomic_read(&m->nr_valid_paths) == 0 &&
 	    !test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) {
 		dm_report_EIO(m);
-		return -EIO;
+		error = -EIO;
+		goto done;
 	}
 
 	/* Queue for the daemon to resubmit */
@@ -1539,28 +1541,16 @@ static int do_end_io_bio(struct multipath *m, struct bio *clone,
 	if (!test_bit(MPATHF_QUEUE_IO, &m->flags))
 		queue_work(kmultipathd, &m->process_queued_bios);
 
-	return DM_ENDIO_INCOMPLETE;
-}
-
-static int multipath_end_io_bio(struct dm_target *ti, struct bio *clone, int error)
-{
-	struct multipath *m = ti->private;
-	struct dm_mpath_io *mpio = get_mpio_from_bio(clone);
-	struct pgpath *pgpath;
-	struct path_selector *ps;
-	int r;
-
-	BUG_ON(!mpio);
-
-	r = do_end_io_bio(m, clone, error, mpio);
-	pgpath = mpio->pgpath;
+	error = DM_ENDIO_INCOMPLETE;
+done:
 	if (pgpath) {
-		ps = &pgpath->pg->ps;
+		struct path_selector *ps = &pgpath->pg->ps;
+
 		if (ps->type->end_io)
 			ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes);
 	}
 
-	return r;
+	return error;
 }
 
 /*
-- 
2.11.0

Re: [dm-devel] [PATCH 08/15] dm mpath: merge do_end_io_bio into multipath_end_io_bio

[Martin Wilck]

On Thu, 2017-05-18 at 15:18 +0200, Christoph Hellwig wrote:
> This simplifies the code and especially the error passing a bit and
> will help with the next patch.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  drivers/md/dm-mpath.c | 42 ++++++++++++++++-------------------------
> -
>  1 file changed, 16 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
> index 3df056b73b66..b1cb0273b081 100644
> --- a/drivers/md/dm-mpath.c
> +++ b/drivers/md/dm-mpath.c
> @@ -1510,24 +1510,26 @@ static int multipath_end_io(struct dm_target
> *ti, struct request *clone,
>  	return r;
>  }
>  
> -static int do_end_io_bio(struct multipath *m, struct bio *clone,
> -			 int error, struct dm_mpath_io *mpio)
> +static int multipath_end_io_bio(struct dm_target *ti, struct bio
> *clone, int error)
>  {
> +	struct multipath *m = ti->private;
> +	struct dm_mpath_io *mpio = get_mpio_from_bio(clone);
> +	struct pgpath *pgpath = mpio->pgpath;
>  	unsigned long flags;
>  
> -	if (!error)
> -		return 0;	/* I/O complete */
> +	BUG_ON(!mpio);

You dereferenced mpio already above.

Regards,
Martin

>  
> -	if (noretry_error(error))
> -		return error;
> +	if (!error || noretry_error(error))
> +		goto done;
>  
> -	if (mpio->pgpath)
> -		fail_path(mpio->pgpath);
> +	if (pgpath)
> +		fail_path(pgpath);
>  
>  	if (atomic_read(&m->nr_valid_paths) == 0 &&
>  	    !test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) {
>  		dm_report_EIO(m);
> -		return -EIO;
> +		error = -EIO;
> +		goto done;
>  	}
>  
>  	/* Queue for the daemon to resubmit */
> @@ -1539,28 +1541,16 @@ static int do_end_io_bio(struct multipath *m,
> struct bio *clone,
>  	if (!test_bit(MPATHF_QUEUE_IO, &m->flags))
>  		queue_work(kmultipathd, &m->process_queued_bios);
>  
> -	return DM_ENDIO_INCOMPLETE;
> -}
> -
> -static int multipath_end_io_bio(struct dm_target *ti, struct bio
> *clone, int error)
> -{
> -	struct multipath *m = ti->private;
> -	struct dm_mpath_io *mpio = get_mpio_from_bio(clone);
> -	struct pgpath *pgpath;
> -	struct path_selector *ps;
> -	int r;
> -
> -	BUG_ON(!mpio);
> -
> -	r = do_end_io_bio(m, clone, error, mpio);
> -	pgpath = mpio->pgpath;
> +	error = DM_ENDIO_INCOMPLETE;
> +done:
>  	if (pgpath) {
> -		ps = &pgpath->pg->ps;
> +		struct path_selector *ps = &pgpath->pg->ps;
> +
>  		if (ps->type->end_io)
>  			ps->type->end_io(ps, &pgpath->path, mpio-
> >nr_bytes);
>  	}
>  
> -	return r;
> +	return error;
>  }
>  
>  /*

-- 
Dr. Martin Wilck <mwilck@suse.com>, Tel. +49 (0)911 74053 2107
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)

Re: [dm-devel] [PATCH 08/15] dm mpath: merge do_end_io_bio into multipath_end_io_bio

[Christoph Hellwig]

On Mon, May 22, 2017 at 08:51:20PM +0200, Martin Wilck wrote:
> >  
> > -	if (!error)
> > -		return 0;	/* I/O complete */
> > +	BUG_ON(!mpio);
> 
> You dereferenced mpio already above.

Indeed.  I removed the BUG_ON for the next version.

[PATCH 09/15] dm: don't return errnos from ->map

[Christoph Hellwig]

Instead use the special DM_MAPIO_KILL return value to return -EIO just
like we do for the request based path.  Note that dm-log-writes returned
-ENOMEM in a few places, which now becomes -EIO instead.  No consumer
treats -ENOMEM special so this shouldn't be an issue (and it should
use a mempool to start with to make guaranteed progress).

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/md/dm-crypt.c         |  4 ++--
 drivers/md/dm-flakey.c        |  4 ++--
 drivers/md/dm-integrity.c     | 12 ++++++------
 drivers/md/dm-log-writes.c    |  4 ++--
 drivers/md/dm-mpath.c         | 13 ++++++++++---
 drivers/md/dm-raid1.c         |  6 +++---
 drivers/md/dm-snap.c          |  8 ++++----
 drivers/md/dm-target.c        |  2 +-
 drivers/md/dm-verity-target.c |  6 +++---
 drivers/md/dm-zero.c          |  4 ++--
 drivers/md/dm.c               | 16 +++++++++++-----
 11 files changed, 46 insertions(+), 33 deletions(-)

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index ebf9e72d479b..f4b51809db21 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -2795,10 +2795,10 @@ static int crypt_map(struct dm_target *ti, struct bio *bio)
 	 * and is aligned to this size as defined in IO hints.
 	 */
 	if (unlikely((bio->bi_iter.bi_sector & ((cc->sector_size >> SECTOR_SHIFT) - 1)) != 0))
-		return -EIO;
+		return DM_MAPIO_KILL;
 
 	if (unlikely(bio->bi_iter.bi_size & (cc->sector_size - 1)))
-		return -EIO;
+		return DM_MAPIO_KILL;
 
 	io = dm_per_bio_data(bio, cc->per_bio_data_size);
 	crypt_io_init(io, cc, bio, dm_target_offset(ti, bio->bi_iter.bi_sector));
diff --git a/drivers/md/dm-flakey.c b/drivers/md/dm-flakey.c
index 13305a182611..e8f093b323ce 100644
--- a/drivers/md/dm-flakey.c
+++ b/drivers/md/dm-flakey.c
@@ -321,7 +321,7 @@ static int flakey_map(struct dm_target *ti, struct bio *bio)
 		if (bio_data_dir(bio) == READ) {
 			if (!fc->corrupt_bio_byte && !test_bit(DROP_WRITES, &fc->flags) &&
 			    !test_bit(ERROR_WRITES, &fc->flags))
-				return -EIO;
+				return DM_MAPIO_KILL;
 			goto map_bio;
 		}
 
@@ -349,7 +349,7 @@ static int flakey_map(struct dm_target *ti, struct bio *bio)
 		/*
 		 * By default, error all I/O.
 		 */
-		return -EIO;
+		return DM_MAPIO_KILL;
 	}
 
 map_bio:
diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index c7f7c8d76576..ee78fb471229 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -1352,13 +1352,13 @@ static int dm_integrity_map(struct dm_target *ti, struct bio *bio)
 		DMERR("Too big sector number: 0x%llx + 0x%x > 0x%llx",
 		      (unsigned long long)dio->range.logical_sector, bio_sectors(bio),
 		      (unsigned long long)ic->provided_data_sectors);
-		return -EIO;
+		return DM_MAPIO_KILL;
 	}
 	if (unlikely((dio->range.logical_sector | bio_sectors(bio)) & (unsigned)(ic->sectors_per_block - 1))) {
 		DMERR("Bio not aligned on %u sectors: 0x%llx, 0x%x",
 		      ic->sectors_per_block,
 		      (unsigned long long)dio->range.logical_sector, bio_sectors(bio));
-		return -EIO;
+		return DM_MAPIO_KILL;
 	}
 
 	if (ic->sectors_per_block > 1) {
@@ -1368,7 +1368,7 @@ static int dm_integrity_map(struct dm_target *ti, struct bio *bio)
 			if (unlikely((bv.bv_offset | bv.bv_len) & ((ic->sectors_per_block << SECTOR_SHIFT) - 1))) {
 				DMERR("Bio vector (%u,%u) is not aligned on %u-sector boundary",
 					bv.bv_offset, bv.bv_len, ic->sectors_per_block);
-				return -EIO;
+				return DM_MAPIO_KILL;
 			}
 		}
 	}
@@ -1383,18 +1383,18 @@ static int dm_integrity_map(struct dm_target *ti, struct bio *bio)
 				wanted_tag_size *= ic->tag_size;
 			if (unlikely(wanted_tag_size != bip->bip_iter.bi_size)) {
 				DMERR("Invalid integrity data size %u, expected %u", bip->bip_iter.bi_size, wanted_tag_size);
-				return -EIO;
+				return DM_MAPIO_KILL;
 			}
 		}
 	} else {
 		if (unlikely(bip != NULL)) {
 			DMERR("Unexpected integrity data when using internal hash");
-			return -EIO;
+			return DM_MAPIO_KILL;
 		}
 	}
 
 	if (unlikely(ic->mode == 'R') && unlikely(dio->write))
-		return -EIO;
+		return DM_MAPIO_KILL;
 
 	get_area_and_offset(ic, dio->range.logical_sector, &area, &offset);
 	dio->metadata_block = get_metadata_sector_and_offset(ic, area, offset, &dio->metadata_offset);
diff --git a/drivers/md/dm-log-writes.c b/drivers/md/dm-log-writes.c
index 4dfe38655a49..e42264706c59 100644
--- a/drivers/md/dm-log-writes.c
+++ b/drivers/md/dm-log-writes.c
@@ -586,7 +586,7 @@ static int log_writes_map(struct dm_target *ti, struct bio *bio)
 		spin_lock_irq(&lc->blocks_lock);
 		lc->logging_enabled = false;
 		spin_unlock_irq(&lc->blocks_lock);
-		return -ENOMEM;
+		return DM_MAPIO_KILL;
 	}
 	INIT_LIST_HEAD(&block->list);
 	pb->block = block;
@@ -639,7 +639,7 @@ static int log_writes_map(struct dm_target *ti, struct bio *bio)
 			spin_lock_irq(&lc->blocks_lock);
 			lc->logging_enabled = false;
 			spin_unlock_irq(&lc->blocks_lock);
-			return -ENOMEM;
+			return DM_MAPIO_KILL;
 		}
 
 		src = kmap_atomic(bv.bv_page);
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index b1cb0273b081..94b1aa917fcb 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -559,7 +559,7 @@ static int __multipath_map_bio(struct multipath *m, struct bio *bio, struct dm_m
 		if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))
 			return DM_MAPIO_REQUEUE;
 		dm_report_EIO(m);
-		return -EIO;
+		return DM_MAPIO_KILL;
 	}
 
 	mpio->pgpath = pgpath;
@@ -621,11 +621,18 @@ static void process_queued_bios(struct work_struct *work)
 	blk_start_plug(&plug);
 	while ((bio = bio_list_pop(&bios))) {
 		r = __multipath_map_bio(m, bio, get_mpio_from_bio(bio));
-		if (r < 0 || r == DM_MAPIO_REQUEUE) {
+		switch (r) {
+		case DM_MAPIO_KILL:
+			r = -EIO;
+			/*FALLTHRU*/
+		case DM_MAPIO_REQUEUE:
 			bio->bi_error = r;
 			bio_endio(bio);
-		} else if (r == DM_MAPIO_REMAPPED)
+			break;
+		case DM_MAPIO_REMAPPED:
 			generic_make_request(bio);
+			break;
+		}
 	}
 	blk_finish_plug(&plug);
 }
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index 5e30b08b91d9..d9c0c6a77eb5 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -1207,14 +1207,14 @@ static int mirror_map(struct dm_target *ti, struct bio *bio)
 
 	r = log->type->in_sync(log, dm_rh_bio_to_region(ms->rh, bio), 0);
 	if (r < 0 && r != -EWOULDBLOCK)
-		return r;
+		return DM_MAPIO_KILL;
 
 	/*
 	 * If region is not in-sync queue the bio.
 	 */
 	if (!r || (r == -EWOULDBLOCK)) {
 		if (bio->bi_opf & REQ_RAHEAD)
-			return -EIO;
+			return DM_MAPIO_KILL;
 
 		queue_bio(ms, bio, rw);
 		return DM_MAPIO_SUBMITTED;
@@ -1226,7 +1226,7 @@ static int mirror_map(struct dm_target *ti, struct bio *bio)
 	 */
 	m = choose_mirror(ms, bio->bi_iter.bi_sector);
 	if (unlikely(!m))
-		return -EIO;
+		return DM_MAPIO_KILL;
 
 	dm_bio_record(&bio_record->details, bio);
 	bio_record->m = m;
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index e152d9817c81..5a7f73f9a6fb 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -1690,7 +1690,7 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio)
 	/* Full snapshots are not usable */
 	/* To get here the table must be live so s->active is always set. */
 	if (!s->valid)
-		return -EIO;
+		return DM_MAPIO_KILL;
 
 	/* FIXME: should only take write lock if we need
 	 * to copy an exception */
@@ -1698,7 +1698,7 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio)
 
 	if (!s->valid || (unlikely(s->snapshot_overflowed) &&
 	    bio_data_dir(bio) == WRITE)) {
-		r = -EIO;
+		r = DM_MAPIO_KILL;
 		goto out_unlock;
 	}
 
@@ -1723,7 +1723,7 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio)
 
 			if (!s->valid || s->snapshot_overflowed) {
 				free_pending_exception(pe);
-				r = -EIO;
+				r = DM_MAPIO_KILL;
 				goto out_unlock;
 			}
 
@@ -1741,7 +1741,7 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio)
 					DMERR("Snapshot overflowed: Unable to allocate exception.");
 				} else
 					__invalidate_snapshot(s, -ENOMEM);
-				r = -EIO;
+				r = DM_MAPIO_KILL;
 				goto out_unlock;
 			}
 		}
diff --git a/drivers/md/dm-target.c b/drivers/md/dm-target.c
index b242b750542f..c0d7e60820c4 100644
--- a/drivers/md/dm-target.c
+++ b/drivers/md/dm-target.c
@@ -128,7 +128,7 @@ static void io_err_dtr(struct dm_target *tt)
 
 static int io_err_map(struct dm_target *tt, struct bio *bio)
 {
-	return -EIO;
+	return DM_MAPIO_KILL;
 }
 
 static int io_err_clone_and_map_rq(struct dm_target *ti, struct request *rq,
diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
index 97de961a3bfc..9ed55468b98b 100644
--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -643,17 +643,17 @@ static int verity_map(struct dm_target *ti, struct bio *bio)
 	if (((unsigned)bio->bi_iter.bi_sector | bio_sectors(bio)) &
 	    ((1 << (v->data_dev_block_bits - SECTOR_SHIFT)) - 1)) {
 		DMERR_LIMIT("unaligned io");
-		return -EIO;
+		return DM_MAPIO_KILL;
 	}
 
 	if (bio_end_sector(bio) >>
 	    (v->data_dev_block_bits - SECTOR_SHIFT) > v->data_blocks) {
 		DMERR_LIMIT("io out of range");
-		return -EIO;
+		return DM_MAPIO_KILL;
 	}
 
 	if (bio_data_dir(bio) == WRITE)
-		return -EIO;
+		return DM_MAPIO_KILL;
 
 	io = dm_per_bio_data(bio, ti->per_io_data_size);
 	io->v = v;
diff --git a/drivers/md/dm-zero.c b/drivers/md/dm-zero.c
index b616f11d8473..b65ca8dcfbdc 100644
--- a/drivers/md/dm-zero.c
+++ b/drivers/md/dm-zero.c
@@ -39,7 +39,7 @@ static int zero_map(struct dm_target *ti, struct bio *bio)
 	case REQ_OP_READ:
 		if (bio->bi_opf & REQ_RAHEAD) {
 			/* readahead of null bytes only wastes buffer cache */
-			return -EIO;
+			return DM_MAPIO_KILL;
 		}
 		zero_fill_bio(bio);
 		break;
@@ -47,7 +47,7 @@ static int zero_map(struct dm_target *ti, struct bio *bio)
 		/* writes get silently dropped */
 		break;
 	default:
-		return -EIO;
+		return DM_MAPIO_KILL;
 	}
 
 	bio_endio(bio);
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 6ef9500226c0..499f8209bacf 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1084,18 +1084,24 @@ static void __map_bio(struct dm_target_io *tio)
 	r = ti->type->map(ti, clone);
 	dm_offload_end(&o);
 
-	if (r == DM_MAPIO_REMAPPED) {
+	switch (r) {
+	case DM_MAPIO_SUBMITTED:
+		break;
+	case DM_MAPIO_REMAPPED:
 		/* the bio has been remapped so dispatch it */
-
 		trace_block_bio_remap(bdev_get_queue(clone->bi_bdev), clone,
 				      tio->io->bio->bi_bdev->bd_dev, sector);
-
 		generic_make_request(clone);
-	} else if (r < 0 || r == DM_MAPIO_REQUEUE) {
+		break;
+	case DM_MAPIO_KILL:
+		r = -EIO;
+		/*FALLTHRU*/
+	case DM_MAPIO_REQUEUE:
 		/* error the io and bail out, or requeue it if needed */
 		dec_pending(tio->io, r);
 		free_tio(tio);
-	} else if (r != DM_MAPIO_SUBMITTED) {
+		break;
+	default:
 		DMWARN("unimplemented target map return value: %d", r);
 		BUG();
 	}
-- 
2.11.0

[PATCH 10/15] dm: change ->end_io calling convention

[Christoph Hellwig]

Turn the error paramter into a pointer so that target drivers can change
the value, and make sure only DM_ENDIO_* values are returned from the
methods.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/md/dm-cache-target.c  |  4 ++--
 drivers/md/dm-flakey.c        |  8 ++++----
 drivers/md/dm-log-writes.c    |  4 ++--
 drivers/md/dm-mpath.c         | 11 ++++++-----
 drivers/md/dm-raid1.c         | 14 +++++++-------
 drivers/md/dm-snap.c          |  4 ++--
 drivers/md/dm-stripe.c        | 14 +++++++-------
 drivers/md/dm-thin.c          |  4 ++--
 drivers/md/dm.c               | 36 ++++++++++++++++++------------------
 include/linux/device-mapper.h |  2 +-
 10 files changed, 51 insertions(+), 50 deletions(-)

diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index d682a0511381..c48612e6d525 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -2820,7 +2820,7 @@ static int cache_map(struct dm_target *ti, struct bio *bio)
 	return r;
 }
 
-static int cache_end_io(struct dm_target *ti, struct bio *bio, int error)
+static int cache_end_io(struct dm_target *ti, struct bio *bio, int *error)
 {
 	struct cache *cache = ti->private;
 	unsigned long flags;
@@ -2838,7 +2838,7 @@ static int cache_end_io(struct dm_target *ti, struct bio *bio, int error)
 	bio_drop_shared_lock(cache, bio);
 	accounted_complete(cache, bio);
 
-	return 0;
+	return DM_ENDIO_DONE;
 }
 
 static int write_dirty_bitset(struct cache *cache)
diff --git a/drivers/md/dm-flakey.c b/drivers/md/dm-flakey.c
index e8f093b323ce..c9539917a59b 100644
--- a/drivers/md/dm-flakey.c
+++ b/drivers/md/dm-flakey.c
@@ -358,12 +358,12 @@ static int flakey_map(struct dm_target *ti, struct bio *bio)
 	return DM_MAPIO_REMAPPED;
 }
 
-static int flakey_end_io(struct dm_target *ti, struct bio *bio, int error)
+static int flakey_end_io(struct dm_target *ti, struct bio *bio, int *error)
 {
 	struct flakey_c *fc = ti->private;
 	struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
 
-	if (!error && pb->bio_submitted && (bio_data_dir(bio) == READ)) {
+	if (!*error && pb->bio_submitted && (bio_data_dir(bio) == READ)) {
 		if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == READ) &&
 		    all_corrupt_bio_flags_match(bio, fc)) {
 			/*
@@ -377,11 +377,11 @@ static int flakey_end_io(struct dm_target *ti, struct bio *bio, int error)
 			 * Error read during the down_interval if drop_writes
 			 * and error_writes were not configured.
 			 */
-			return -EIO;
+			*error = -EIO;
 		}
 	}
 
-	return error;
+	return DM_ENDIO_DONE;
 }
 
 static void flakey_status(struct dm_target *ti, status_type_t type,
diff --git a/drivers/md/dm-log-writes.c b/drivers/md/dm-log-writes.c
index e42264706c59..cc57c7fa1268 100644
--- a/drivers/md/dm-log-writes.c
+++ b/drivers/md/dm-log-writes.c
@@ -664,7 +664,7 @@ static int log_writes_map(struct dm_target *ti, struct bio *bio)
 	return DM_MAPIO_REMAPPED;
 }
 
-static int normal_end_io(struct dm_target *ti, struct bio *bio, int error)
+static int normal_end_io(struct dm_target *ti, struct bio *bio, int *error)
 {
 	struct log_writes_c *lc = ti->private;
 	struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
@@ -686,7 +686,7 @@ static int normal_end_io(struct dm_target *ti, struct bio *bio, int error)
 		spin_unlock_irqrestore(&lc->blocks_lock, flags);
 	}
 
-	return error;
+	return DM_ENDIO_DONE;
 }
 
 /*
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 94b1aa917fcb..14f5b0d4ecce 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -1517,16 +1517,17 @@ static int multipath_end_io(struct dm_target *ti, struct request *clone,
 	return r;
 }
 
-static int multipath_end_io_bio(struct dm_target *ti, struct bio *clone, int error)
+static int multipath_end_io_bio(struct dm_target *ti, struct bio *clone, int *error)
 {
 	struct multipath *m = ti->private;
 	struct dm_mpath_io *mpio = get_mpio_from_bio(clone);
 	struct pgpath *pgpath = mpio->pgpath;
 	unsigned long flags;
+	int r = DM_ENDIO_DONE;
 
 	BUG_ON(!mpio);
 
-	if (!error || noretry_error(error))
+	if (!*error || noretry_error(*error))
 		goto done;
 
 	if (pgpath)
@@ -1535,7 +1536,7 @@ static int multipath_end_io_bio(struct dm_target *ti, struct bio *clone, int err
 	if (atomic_read(&m->nr_valid_paths) == 0 &&
 	    !test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) {
 		dm_report_EIO(m);
-		error = -EIO;
+		*error = -EIO;
 		goto done;
 	}
 
@@ -1548,7 +1549,7 @@ static int multipath_end_io_bio(struct dm_target *ti, struct bio *clone, int err
 	if (!test_bit(MPATHF_QUEUE_IO, &m->flags))
 		queue_work(kmultipathd, &m->process_queued_bios);
 
-	error = DM_ENDIO_INCOMPLETE;
+	r = DM_ENDIO_INCOMPLETE;
 done:
 	if (pgpath) {
 		struct path_selector *ps = &pgpath->pg->ps;
@@ -1557,7 +1558,7 @@ static int multipath_end_io_bio(struct dm_target *ti, struct bio *clone, int err
 			ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes);
 	}
 
-	return error;
+	return r;
 }
 
 /*
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index d9c0c6a77eb5..77bcf50ce75f 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -1236,7 +1236,7 @@ static int mirror_map(struct dm_target *ti, struct bio *bio)
 	return DM_MAPIO_REMAPPED;
 }
 
-static int mirror_end_io(struct dm_target *ti, struct bio *bio, int error)
+static int mirror_end_io(struct dm_target *ti, struct bio *bio, int *error)
 {
 	int rw = bio_data_dir(bio);
 	struct mirror_set *ms = (struct mirror_set *) ti->private;
@@ -1252,16 +1252,16 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio, int error)
 		if (!(bio->bi_opf & REQ_PREFLUSH) &&
 		    bio_op(bio) != REQ_OP_DISCARD)
 			dm_rh_dec(ms->rh, bio_record->write_region);
-		return error;
+		return DM_ENDIO_DONE;
 	}
 
-	if (error == -EOPNOTSUPP)
-		return error;
+	if (*error == -EOPNOTSUPP)
+		return DM_ENDIO_DONE;
 
 	if (bio->bi_opf & REQ_RAHEAD)
-		return error;
+		return DM_ENDIO_DONE;
 
-	if (unlikely(error)) {
+	if (unlikely(*error)) {
 		m = bio_record->m;
 
 		DMERR("Mirror read failed from %s. Trying alternative device.",
@@ -1285,7 +1285,7 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio, int error)
 		DMERR("All replicated volumes dead, failing I/O");
 	}
 
-	return error;
+	return DM_ENDIO_DONE;
 }
 
 static void mirror_presuspend(struct dm_target *ti)
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 5a7f73f9a6fb..79a845798e2f 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -1851,14 +1851,14 @@ static int snapshot_merge_map(struct dm_target *ti, struct bio *bio)
 	return r;
 }
 
-static int snapshot_end_io(struct dm_target *ti, struct bio *bio, int error)
+static int snapshot_end_io(struct dm_target *ti, struct bio *bio, int *error)
 {
 	struct dm_snapshot *s = ti->private;
 
 	if (is_bio_tracked(bio))
 		stop_tracking_chunk(s, bio);
 
-	return 0;
+	return DM_ENDIO_DONE;
 }
 
 static void snapshot_merge_presuspend(struct dm_target *ti)
diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
index 780e95889a7c..49888bc2c909 100644
--- a/drivers/md/dm-stripe.c
+++ b/drivers/md/dm-stripe.c
@@ -375,20 +375,20 @@ static void stripe_status(struct dm_target *ti, status_type_t type,
 	}
 }
 
-static int stripe_end_io(struct dm_target *ti, struct bio *bio, int error)
+static int stripe_end_io(struct dm_target *ti, struct bio *bio, int *error)
 {
 	unsigned i;
 	char major_minor[16];
 	struct stripe_c *sc = ti->private;
 
-	if (!error)
-		return 0; /* I/O complete */
+	if (!*error)
+		return DM_ENDIO_DONE; /* I/O complete */
 
 	if (bio->bi_opf & REQ_RAHEAD)
-		return error;
+		return DM_ENDIO_DONE;
 
-	if (error == -EOPNOTSUPP)
-		return error;
+	if (*error == -EOPNOTSUPP)
+		return DM_ENDIO_DONE;
 
 	memset(major_minor, 0, sizeof(major_minor));
 	sprintf(major_minor, "%d:%d",
@@ -409,7 +409,7 @@ static int stripe_end_io(struct dm_target *ti, struct bio *bio, int error)
 				schedule_work(&sc->trigger_event);
 		}
 
-	return error;
+	return DM_ENDIO_DONE;
 }
 
 static int stripe_iterate_devices(struct dm_target *ti,
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 17ad50daed08..22b1a64c44b7 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -4177,7 +4177,7 @@ static int thin_map(struct dm_target *ti, struct bio *bio)
 	return thin_bio_map(ti, bio);
 }
 
-static int thin_endio(struct dm_target *ti, struct bio *bio, int err)
+static int thin_endio(struct dm_target *ti, struct bio *bio, int *err)
 {
 	unsigned long flags;
 	struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
@@ -4212,7 +4212,7 @@ static int thin_endio(struct dm_target *ti, struct bio *bio, int err)
 	if (h->cell)
 		cell_defer_no_holder(h->tc, h->cell);
 
-	return 0;
+	return DM_ENDIO_DONE;
 }
 
 static void thin_presuspend(struct dm_target *ti)
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 499f8209bacf..7a7047211c64 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -845,24 +845,7 @@ static void clone_endio(struct bio *bio)
 	struct mapped_device *md = tio->io->md;
 	dm_endio_fn endio = tio->ti->type->end_io;
 
-	if (endio) {
-		r = endio(tio->ti, bio, error);
-		if (r < 0 || r == DM_ENDIO_REQUEUE)
-			/*
-			 * error and requeue request are handled
-			 * in dec_pending().
-			 */
-			error = r;
-		else if (r == DM_ENDIO_INCOMPLETE)
-			/* The target will handle the io */
-			return;
-		else if (r) {
-			DMWARN("unimplemented target endio return value: %d", r);
-			BUG();
-		}
-	}
-
-	if (unlikely(r == -EREMOTEIO)) {
+	if (unlikely(error == -EREMOTEIO)) {
 		if (bio_op(bio) == REQ_OP_WRITE_SAME &&
 		    !bdev_get_queue(bio->bi_bdev)->limits.max_write_same_sectors)
 			disable_write_same(md);
@@ -871,6 +854,23 @@ static void clone_endio(struct bio *bio)
 			disable_write_zeroes(md);
 	}
 
+	if (endio) {
+		r = endio(tio->ti, bio, &error);
+		switch (r) {
+		case DM_ENDIO_REQUEUE:
+			error = DM_ENDIO_REQUEUE;
+			/*FALLTHRU*/
+		case DM_ENDIO_DONE:
+			break;
+		case DM_ENDIO_INCOMPLETE:
+			/* The target will handle the io */
+			return;
+		default:
+			DMWARN("unimplemented target endio return value: %d", r);
+			BUG();
+		}
+	}
+
 	free_tio(tio);
 	dec_pending(io, error);
 }
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index f4c639c0c362..dec227acc13b 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -72,7 +72,7 @@ typedef void (*dm_release_clone_request_fn) (struct request *clone);
  * 2   : The target wants to push back the io
  */
 typedef int (*dm_endio_fn) (struct dm_target *ti,
-			    struct bio *bio, int error);
+			    struct bio *bio, int *error);
 typedef int (*dm_request_endio_fn) (struct dm_target *ti,
 				    struct request *clone, int error,
 				    union map_info *map_context);
-- 
2.11.0

[PATCH 11/15] fs-writeback: move wbc_to_write_flags out of line

[Christoph Hellwig]

This way writeback.h doesn't need to pull in blk_types.h.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/fs-writeback.c         | 13 +++++++++++++
 include/linux/writeback.h | 11 +----------
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 63ee2940775c..51b65591afe1 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -59,6 +59,19 @@ struct wb_writeback_work {
 	struct wb_completion *done;	/* set if the caller waits */
 };
 
+#ifdef CONFIG_BLOCK
+int wbc_to_write_flags(struct writeback_control *wbc)
+{
+	if (wbc->sync_mode == WB_SYNC_ALL)
+		return REQ_SYNC;
+	else if (wbc->for_kupdate || wbc->for_background)
+		return REQ_BACKGROUND;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(wbc_to_write_flags);
+#endif
+
 /*
  * If one wants to wait for one or more wb_writeback_works, each work's
  * ->done should be set to a wb_completion defined using the following
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index d5815794416c..c5ae6ef9b317 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -9,7 +9,6 @@
 #include <linux/fs.h>
 #include <linux/flex_proportions.h>
 #include <linux/backing-dev-defs.h>
-#include <linux/blk_types.h>
 
 struct bio;
 
@@ -103,15 +102,7 @@ struct writeback_control {
 #endif
 };
 
-static inline int wbc_to_write_flags(struct writeback_control *wbc)
-{
-	if (wbc->sync_mode == WB_SYNC_ALL)
-		return REQ_SYNC;
-	else if (wbc->for_kupdate || wbc->for_background)
-		return REQ_BACKGROUND;
-
-	return 0;
-}
+int wbc_to_write_flags(struct writeback_control *wbc);
 
 /*
  * A wb_domain represents a domain that wb's (bdi_writeback's) belong to
-- 
2.11.0

[PATCH 12/15] block: merge blk_types.h into bio.h

[Christoph Hellwig]

We've cleaned up our headers sufficiently that we don't need this split
anymore.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-wbt.c                    |   2 +-
 drivers/target/target_core_pscsi.c |   2 +-
 include/linux/bio.h                | 307 +++++++++++++++++++++++++++++++++++-
 include/linux/blk_types.h          | 315 -------------------------------------
 include/linux/swap.h               |   2 +-
 5 files changed, 308 insertions(+), 320 deletions(-)
 delete mode 100644 include/linux/blk_types.h

diff --git a/block/blk-wbt.c b/block/blk-wbt.c
index 17676f4d7fd1..ad355fcda96c 100644
--- a/block/blk-wbt.c
+++ b/block/blk-wbt.c
@@ -19,7 +19,7 @@
  *
  */
 #include <linux/kernel.h>
-#include <linux/blk_types.h>
+#include <linux/bio.h>
 #include <linux/slab.h>
 #include <linux/backing-dev.h>
 #include <linux/swap.h>
diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c
index 3e4abb13f8ea..1fd365ed83d6 100644
--- a/drivers/target/target_core_pscsi.c
+++ b/drivers/target/target_core_pscsi.c
@@ -27,7 +27,7 @@
 #include <linux/parser.h>
 #include <linux/timer.h>
 #include <linux/blkdev.h>
-#include <linux/blk_types.h>
+#include <linux/bio.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/genhd.h>
diff --git a/include/linux/bio.h b/include/linux/bio.h
index d1b04b0e99cf..f6a7c9e65ea0 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -25,10 +25,18 @@
 
 #ifdef CONFIG_BLOCK
 
+#include <linux/types.h>
+#include <linux/bvec.h>
 #include <asm/io.h>
 
-/* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
-#include <linux/blk_types.h>
+struct bio_set;
+struct bio;
+struct bio_integrity_payload;
+struct page;
+struct block_device;
+struct io_context;
+struct cgroup_subsys_state;
+typedef void (bio_end_io_t) (struct bio *);
 
 #define BIO_DEBUG
 
@@ -40,6 +48,301 @@
 
 #define BIO_MAX_PAGES		256
 
+struct blk_issue_stat {
+	u64 stat;
+};
+
+/*
+ * main unit of I/O for the block layer and lower layers (ie drivers and
+ * stacking drivers)
+ */
+struct bio {
+	struct bio		*bi_next;	/* request queue link */
+	struct block_device	*bi_bdev;
+	int			bi_error;
+	unsigned int		bi_opf;		/* bottom bits req flags,
+						 * top bits REQ_OP. Use
+						 * accessors.
+						 */
+	unsigned short		bi_flags;	/* status, etc and bvec pool number */
+	unsigned short		bi_ioprio;
+
+	struct bvec_iter	bi_iter;
+
+	/* Number of segments in this BIO after
+	 * physical address coalescing is performed.
+	 */
+	unsigned int		bi_phys_segments;
+
+	/*
+	 * To keep track of the max segment size, we account for the
+	 * sizes of the first and last mergeable segments in this bio.
+	 */
+	unsigned int		bi_seg_front_size;
+	unsigned int		bi_seg_back_size;
+
+	atomic_t		__bi_remaining;
+
+	bio_end_io_t		*bi_end_io;
+
+	void			*bi_private;
+#ifdef CONFIG_BLK_CGROUP
+	/*
+	 * Optional ioc and css associated with this bio.  Put on bio
+	 * release.  Read comment on top of bio_associate_current().
+	 */
+	struct io_context	*bi_ioc;
+	struct cgroup_subsys_state *bi_css;
+#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
+	void			*bi_cg_private;
+	struct blk_issue_stat	bi_issue_stat;
+#endif
+#endif
+	union {
+#if defined(CONFIG_BLK_DEV_INTEGRITY)
+		struct bio_integrity_payload *bi_integrity; /* data integrity */
+#endif
+	};
+
+	unsigned short		bi_vcnt;	/* how many bio_vec's */
+
+	/*
+	 * Everything starting with bi_max_vecs will be preserved by bio_reset()
+	 */
+
+	unsigned short		bi_max_vecs;	/* max bvl_vecs we can hold */
+
+	atomic_t		__bi_cnt;	/* pin count */
+
+	struct bio_vec		*bi_io_vec;	/* the actual vec list */
+
+	struct bio_set		*bi_pool;
+
+	/*
+	 * We can inline a number of vecs at the end of the bio, to avoid
+	 * double allocations for a small number of bio_vecs. This member
+	 * MUST obviously be kept at the very end of the bio.
+	 */
+	struct bio_vec		bi_inline_vecs[0];
+};
+
+#define BIO_RESET_BYTES		offsetof(struct bio, bi_max_vecs)
+
+/*
+ * bio flags
+ */
+#define BIO_SEG_VALID	1	/* bi_phys_segments valid */
+#define BIO_CLONED	2	/* doesn't own data */
+#define BIO_BOUNCED	3	/* bio is a bounce bio */
+#define BIO_USER_MAPPED 4	/* contains user pages */
+#define BIO_NULL_MAPPED 5	/* contains invalid user pages */
+#define BIO_QUIET	6	/* Make BIO Quiet */
+#define BIO_CHAIN	7	/* chained bio, ->bi_remaining in effect */
+#define BIO_REFFED	8	/* bio has elevated ->bi_cnt */
+#define BIO_THROTTLED	9	/* This bio has already been subjected to
+				 * throttling rules. Don't do it again. */
+#define BIO_TRACE_COMPLETION 10	/* bio_endio() should trace the final completion
+				 * of this bio. */
+/* See BVEC_POOL_OFFSET below before adding new flags */
+
+/*
+ * We support 6 different bvec pools, the last one is magic in that it
+ * is backed by a mempool.
+ */
+#define BVEC_POOL_NR		6
+#define BVEC_POOL_MAX		(BVEC_POOL_NR - 1)
+
+/*
+ * Top 3 bits of bio flags indicate the pool the bvecs came from.  We add
+ * 1 to the actual index so that 0 indicates that there are no bvecs to be
+ * freed.
+ */
+#define BVEC_POOL_BITS		(3)
+#define BVEC_POOL_OFFSET	(16 - BVEC_POOL_BITS)
+#define BVEC_POOL_IDX(bio)	((bio)->bi_flags >> BVEC_POOL_OFFSET)
+#if (1<< BVEC_POOL_BITS) < (BVEC_POOL_NR+1)
+# error "BVEC_POOL_BITS is too small"
+#endif
+
+/*
+ * Flags starting here get preserved by bio_reset() - this includes
+ * only BVEC_POOL_IDX()
+ */
+#define BIO_RESET_BITS	BVEC_POOL_OFFSET
+
+/*
+ * Operations and flags common to the bio and request structures.
+ * We use 8 bits for encoding the operation, and the remaining 24 for flags.
+ *
+ * The least significant bit of the operation number indicates the data
+ * transfer direction:
+ *
+ *   - if the least significant bit is set transfers are TO the device
+ *   - if the least significant bit is not set transfers are FROM the device
+ *
+ * If a operation does not transfer data the least significant bit has no
+ * meaning.
+ */
+#define REQ_OP_BITS	8
+#define REQ_OP_MASK	((1 << REQ_OP_BITS) - 1)
+#define REQ_FLAG_BITS	24
+
+enum req_opf {
+	/* read sectors from the device */
+	REQ_OP_READ		= 0,
+	/* write sectors to the device */
+	REQ_OP_WRITE		= 1,
+	/* flush the volatile write cache */
+	REQ_OP_FLUSH		= 2,
+	/* discard sectors */
+	REQ_OP_DISCARD		= 3,
+	/* get zone information */
+	REQ_OP_ZONE_REPORT	= 4,
+	/* securely erase sectors */
+	REQ_OP_SECURE_ERASE	= 5,
+	/* seset a zone write pointer */
+	REQ_OP_ZONE_RESET	= 6,
+	/* write the same sector many times */
+	REQ_OP_WRITE_SAME	= 7,
+	/* write the zero filled sector many times */
+	REQ_OP_WRITE_ZEROES	= 9,
+
+	/* SCSI passthrough using struct scsi_request */
+	REQ_OP_SCSI_IN		= 32,
+	REQ_OP_SCSI_OUT		= 33,
+	/* Driver private requests */
+	REQ_OP_DRV_IN		= 34,
+	REQ_OP_DRV_OUT		= 35,
+
+	REQ_OP_LAST,
+};
+
+enum req_flag_bits {
+	__REQ_FAILFAST_DEV =	/* no driver retries of device errors */
+		REQ_OP_BITS,
+	__REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
+	__REQ_FAILFAST_DRIVER,	/* no driver retries of driver errors */
+	__REQ_SYNC,		/* request is sync (sync write or read) */
+	__REQ_META,		/* metadata io request */
+	__REQ_PRIO,		/* boost priority in cfq */
+	__REQ_NOMERGE,		/* don't touch this for merging */
+	__REQ_IDLE,		/* anticipate more IO after this one */
+	__REQ_INTEGRITY,	/* I/O includes block integrity payload */
+	__REQ_FUA,		/* forced unit access */
+	__REQ_PREFLUSH,		/* request for cache flush */
+	__REQ_RAHEAD,		/* read ahead, can fail anytime */
+	__REQ_BACKGROUND,	/* background IO */
+
+	/* command specific flags for REQ_OP_WRITE_ZEROES: */
+	__REQ_NOUNMAP,		/* do not free blocks when zeroing */
+
+	__REQ_NR_BITS,		/* stops here */
+};
+
+#define REQ_FAILFAST_DEV	(1ULL << __REQ_FAILFAST_DEV)
+#define REQ_FAILFAST_TRANSPORT	(1ULL << __REQ_FAILFAST_TRANSPORT)
+#define REQ_FAILFAST_DRIVER	(1ULL << __REQ_FAILFAST_DRIVER)
+#define REQ_SYNC		(1ULL << __REQ_SYNC)
+#define REQ_META		(1ULL << __REQ_META)
+#define REQ_PRIO		(1ULL << __REQ_PRIO)
+#define REQ_NOMERGE		(1ULL << __REQ_NOMERGE)
+#define REQ_IDLE		(1ULL << __REQ_IDLE)
+#define REQ_INTEGRITY		(1ULL << __REQ_INTEGRITY)
+#define REQ_FUA			(1ULL << __REQ_FUA)
+#define REQ_PREFLUSH		(1ULL << __REQ_PREFLUSH)
+#define REQ_RAHEAD		(1ULL << __REQ_RAHEAD)
+#define REQ_BACKGROUND		(1ULL << __REQ_BACKGROUND)
+
+#define REQ_NOUNMAP		(1ULL << __REQ_NOUNMAP)
+
+#define REQ_FAILFAST_MASK \
+	(REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
+
+#define REQ_NOMERGE_FLAGS \
+	(REQ_NOMERGE | REQ_PREFLUSH | REQ_FUA)
+
+#define bio_op(bio) \
+	((bio)->bi_opf & REQ_OP_MASK)
+#define req_op(req) \
+	((req)->cmd_flags & REQ_OP_MASK)
+
+/* obsolete, don't use in new code */
+static inline void bio_set_op_attrs(struct bio *bio, unsigned op,
+		unsigned op_flags)
+{
+	bio->bi_opf = op | op_flags;
+}
+
+static inline bool op_is_write(unsigned int op)
+{
+	return (op & 1);
+}
+
+/*
+ * Check if the bio or request is one that needs special treatment in the
+ * flush state machine.
+ */
+static inline bool op_is_flush(unsigned int op)
+{
+	return op & (REQ_FUA | REQ_PREFLUSH);
+}
+
+/*
+ * Reads are always treated as synchronous, as are requests with the FUA or
+ * PREFLUSH flag.  Other operations may be marked as synchronous using the
+ * REQ_SYNC flag.
+ */
+static inline bool op_is_sync(unsigned int op)
+{
+	return (op & REQ_OP_MASK) == REQ_OP_READ ||
+		(op & (REQ_SYNC | REQ_FUA | REQ_PREFLUSH));
+}
+
+typedef unsigned int blk_qc_t;
+#define BLK_QC_T_NONE		-1U
+#define BLK_QC_T_SHIFT		16
+#define BLK_QC_T_INTERNAL	(1U << 31)
+
+static inline bool blk_qc_t_valid(blk_qc_t cookie)
+{
+	return cookie != BLK_QC_T_NONE;
+}
+
+static inline blk_qc_t blk_tag_to_qc_t(unsigned int tag, unsigned int queue_num,
+				       bool internal)
+{
+	blk_qc_t ret = tag | (queue_num << BLK_QC_T_SHIFT);
+
+	if (internal)
+		ret |= BLK_QC_T_INTERNAL;
+
+	return ret;
+}
+
+static inline unsigned int blk_qc_t_to_queue_num(blk_qc_t cookie)
+{
+	return (cookie & ~BLK_QC_T_INTERNAL) >> BLK_QC_T_SHIFT;
+}
+
+static inline unsigned int blk_qc_t_to_tag(blk_qc_t cookie)
+{
+	return cookie & ((1u << BLK_QC_T_SHIFT) - 1);
+}
+
+static inline bool blk_qc_t_is_internal(blk_qc_t cookie)
+{
+	return (cookie & BLK_QC_T_INTERNAL) != 0;
+}
+
+struct blk_rq_stat {
+	s64 mean;
+	u64 min;
+	u64 max;
+	s32 nr_samples;
+	s32 nr_batch;
+	u64 batch;
+};
+
 #define bio_prio(bio)			(bio)->bi_ioprio
 #define bio_set_prio(bio, prio)		((bio)->bi_ioprio = prio)
 
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
deleted file mode 100644
index 61339bc44400..000000000000
--- a/include/linux/blk_types.h
+++ /dev/null
@@ -1,315 +0,0 @@
-/*
- * Block data types and constants.  Directly include this file only to
- * break include dependency loop.
- */
-#ifndef __LINUX_BLK_TYPES_H
-#define __LINUX_BLK_TYPES_H
-
-#include <linux/types.h>
-#include <linux/bvec.h>
-
-struct bio_set;
-struct bio;
-struct bio_integrity_payload;
-struct page;
-struct block_device;
-struct io_context;
-struct cgroup_subsys_state;
-typedef void (bio_end_io_t) (struct bio *);
-
-struct blk_issue_stat {
-	u64 stat;
-};
-
-/*
- * main unit of I/O for the block layer and lower layers (ie drivers and
- * stacking drivers)
- */
-struct bio {
-	struct bio		*bi_next;	/* request queue link */
-	struct block_device	*bi_bdev;
-	int			bi_error;
-	unsigned int		bi_opf;		/* bottom bits req flags,
-						 * top bits REQ_OP. Use
-						 * accessors.
-						 */
-	unsigned short		bi_flags;	/* status, etc and bvec pool number */
-	unsigned short		bi_ioprio;
-
-	struct bvec_iter	bi_iter;
-
-	/* Number of segments in this BIO after
-	 * physical address coalescing is performed.
-	 */
-	unsigned int		bi_phys_segments;
-
-	/*
-	 * To keep track of the max segment size, we account for the
-	 * sizes of the first and last mergeable segments in this bio.
-	 */
-	unsigned int		bi_seg_front_size;
-	unsigned int		bi_seg_back_size;
-
-	atomic_t		__bi_remaining;
-
-	bio_end_io_t		*bi_end_io;
-
-	void			*bi_private;
-#ifdef CONFIG_BLK_CGROUP
-	/*
-	 * Optional ioc and css associated with this bio.  Put on bio
-	 * release.  Read comment on top of bio_associate_current().
-	 */
-	struct io_context	*bi_ioc;
-	struct cgroup_subsys_state *bi_css;
-#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
-	void			*bi_cg_private;
-	struct blk_issue_stat	bi_issue_stat;
-#endif
-#endif
-	union {
-#if defined(CONFIG_BLK_DEV_INTEGRITY)
-		struct bio_integrity_payload *bi_integrity; /* data integrity */
-#endif
-	};
-
-	unsigned short		bi_vcnt;	/* how many bio_vec's */
-
-	/*
-	 * Everything starting with bi_max_vecs will be preserved by bio_reset()
-	 */
-
-	unsigned short		bi_max_vecs;	/* max bvl_vecs we can hold */
-
-	atomic_t		__bi_cnt;	/* pin count */
-
-	struct bio_vec		*bi_io_vec;	/* the actual vec list */
-
-	struct bio_set		*bi_pool;
-
-	/*
-	 * We can inline a number of vecs at the end of the bio, to avoid
-	 * double allocations for a small number of bio_vecs. This member
-	 * MUST obviously be kept at the very end of the bio.
-	 */
-	struct bio_vec		bi_inline_vecs[0];
-};
-
-#define BIO_RESET_BYTES		offsetof(struct bio, bi_max_vecs)
-
-/*
- * bio flags
- */
-#define BIO_SEG_VALID	1	/* bi_phys_segments valid */
-#define BIO_CLONED	2	/* doesn't own data */
-#define BIO_BOUNCED	3	/* bio is a bounce bio */
-#define BIO_USER_MAPPED 4	/* contains user pages */
-#define BIO_NULL_MAPPED 5	/* contains invalid user pages */
-#define BIO_QUIET	6	/* Make BIO Quiet */
-#define BIO_CHAIN	7	/* chained bio, ->bi_remaining in effect */
-#define BIO_REFFED	8	/* bio has elevated ->bi_cnt */
-#define BIO_THROTTLED	9	/* This bio has already been subjected to
-				 * throttling rules. Don't do it again. */
-#define BIO_TRACE_COMPLETION 10	/* bio_endio() should trace the final completion
-				 * of this bio. */
-/* See BVEC_POOL_OFFSET below before adding new flags */
-
-/*
- * We support 6 different bvec pools, the last one is magic in that it
- * is backed by a mempool.
- */
-#define BVEC_POOL_NR		6
-#define BVEC_POOL_MAX		(BVEC_POOL_NR - 1)
-
-/*
- * Top 3 bits of bio flags indicate the pool the bvecs came from.  We add
- * 1 to the actual index so that 0 indicates that there are no bvecs to be
- * freed.
- */
-#define BVEC_POOL_BITS		(3)
-#define BVEC_POOL_OFFSET	(16 - BVEC_POOL_BITS)
-#define BVEC_POOL_IDX(bio)	((bio)->bi_flags >> BVEC_POOL_OFFSET)
-#if (1<< BVEC_POOL_BITS) < (BVEC_POOL_NR+1)
-# error "BVEC_POOL_BITS is too small"
-#endif
-
-/*
- * Flags starting here get preserved by bio_reset() - this includes
- * only BVEC_POOL_IDX()
- */
-#define BIO_RESET_BITS	BVEC_POOL_OFFSET
-
-/*
- * Operations and flags common to the bio and request structures.
- * We use 8 bits for encoding the operation, and the remaining 24 for flags.
- *
- * The least significant bit of the operation number indicates the data
- * transfer direction:
- *
- *   - if the least significant bit is set transfers are TO the device
- *   - if the least significant bit is not set transfers are FROM the device
- *
- * If a operation does not transfer data the least significant bit has no
- * meaning.
- */
-#define REQ_OP_BITS	8
-#define REQ_OP_MASK	((1 << REQ_OP_BITS) - 1)
-#define REQ_FLAG_BITS	24
-
-enum req_opf {
-	/* read sectors from the device */
-	REQ_OP_READ		= 0,
-	/* write sectors to the device */
-	REQ_OP_WRITE		= 1,
-	/* flush the volatile write cache */
-	REQ_OP_FLUSH		= 2,
-	/* discard sectors */
-	REQ_OP_DISCARD		= 3,
-	/* get zone information */
-	REQ_OP_ZONE_REPORT	= 4,
-	/* securely erase sectors */
-	REQ_OP_SECURE_ERASE	= 5,
-	/* seset a zone write pointer */
-	REQ_OP_ZONE_RESET	= 6,
-	/* write the same sector many times */
-	REQ_OP_WRITE_SAME	= 7,
-	/* write the zero filled sector many times */
-	REQ_OP_WRITE_ZEROES	= 9,
-
-	/* SCSI passthrough using struct scsi_request */
-	REQ_OP_SCSI_IN		= 32,
-	REQ_OP_SCSI_OUT		= 33,
-	/* Driver private requests */
-	REQ_OP_DRV_IN		= 34,
-	REQ_OP_DRV_OUT		= 35,
-
-	REQ_OP_LAST,
-};
-
-enum req_flag_bits {
-	__REQ_FAILFAST_DEV =	/* no driver retries of device errors */
-		REQ_OP_BITS,
-	__REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
-	__REQ_FAILFAST_DRIVER,	/* no driver retries of driver errors */
-	__REQ_SYNC,		/* request is sync (sync write or read) */
-	__REQ_META,		/* metadata io request */
-	__REQ_PRIO,		/* boost priority in cfq */
-	__REQ_NOMERGE,		/* don't touch this for merging */
-	__REQ_IDLE,		/* anticipate more IO after this one */
-	__REQ_INTEGRITY,	/* I/O includes block integrity payload */
-	__REQ_FUA,		/* forced unit access */
-	__REQ_PREFLUSH,		/* request for cache flush */
-	__REQ_RAHEAD,		/* read ahead, can fail anytime */
-	__REQ_BACKGROUND,	/* background IO */
-
-	/* command specific flags for REQ_OP_WRITE_ZEROES: */
-	__REQ_NOUNMAP,		/* do not free blocks when zeroing */
-
-	__REQ_NR_BITS,		/* stops here */
-};
-
-#define REQ_FAILFAST_DEV	(1ULL << __REQ_FAILFAST_DEV)
-#define REQ_FAILFAST_TRANSPORT	(1ULL << __REQ_FAILFAST_TRANSPORT)
-#define REQ_FAILFAST_DRIVER	(1ULL << __REQ_FAILFAST_DRIVER)
-#define REQ_SYNC		(1ULL << __REQ_SYNC)
-#define REQ_META		(1ULL << __REQ_META)
-#define REQ_PRIO		(1ULL << __REQ_PRIO)
-#define REQ_NOMERGE		(1ULL << __REQ_NOMERGE)
-#define REQ_IDLE		(1ULL << __REQ_IDLE)
-#define REQ_INTEGRITY		(1ULL << __REQ_INTEGRITY)
-#define REQ_FUA			(1ULL << __REQ_FUA)
-#define REQ_PREFLUSH		(1ULL << __REQ_PREFLUSH)
-#define REQ_RAHEAD		(1ULL << __REQ_RAHEAD)
-#define REQ_BACKGROUND		(1ULL << __REQ_BACKGROUND)
-
-#define REQ_NOUNMAP		(1ULL << __REQ_NOUNMAP)
-
-#define REQ_FAILFAST_MASK \
-	(REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
-
-#define REQ_NOMERGE_FLAGS \
-	(REQ_NOMERGE | REQ_PREFLUSH | REQ_FUA)
-
-#define bio_op(bio) \
-	((bio)->bi_opf & REQ_OP_MASK)
-#define req_op(req) \
-	((req)->cmd_flags & REQ_OP_MASK)
-
-/* obsolete, don't use in new code */
-static inline void bio_set_op_attrs(struct bio *bio, unsigned op,
-		unsigned op_flags)
-{
-	bio->bi_opf = op | op_flags;
-}
-
-static inline bool op_is_write(unsigned int op)
-{
-	return (op & 1);
-}
-
-/*
- * Check if the bio or request is one that needs special treatment in the
- * flush state machine.
- */
-static inline bool op_is_flush(unsigned int op)
-{
-	return op & (REQ_FUA | REQ_PREFLUSH);
-}
-
-/*
- * Reads are always treated as synchronous, as are requests with the FUA or
- * PREFLUSH flag.  Other operations may be marked as synchronous using the
- * REQ_SYNC flag.
- */
-static inline bool op_is_sync(unsigned int op)
-{
-	return (op & REQ_OP_MASK) == REQ_OP_READ ||
-		(op & (REQ_SYNC | REQ_FUA | REQ_PREFLUSH));
-}
-
-typedef unsigned int blk_qc_t;
-#define BLK_QC_T_NONE		-1U
-#define BLK_QC_T_SHIFT		16
-#define BLK_QC_T_INTERNAL	(1U << 31)
-
-static inline bool blk_qc_t_valid(blk_qc_t cookie)
-{
-	return cookie != BLK_QC_T_NONE;
-}
-
-static inline blk_qc_t blk_tag_to_qc_t(unsigned int tag, unsigned int queue_num,
-				       bool internal)
-{
-	blk_qc_t ret = tag | (queue_num << BLK_QC_T_SHIFT);
-
-	if (internal)
-		ret |= BLK_QC_T_INTERNAL;
-
-	return ret;
-}
-
-static inline unsigned int blk_qc_t_to_queue_num(blk_qc_t cookie)
-{
-	return (cookie & ~BLK_QC_T_INTERNAL) >> BLK_QC_T_SHIFT;
-}
-
-static inline unsigned int blk_qc_t_to_tag(blk_qc_t cookie)
-{
-	return cookie & ((1u << BLK_QC_T_SHIFT) - 1);
-}
-
-static inline bool blk_qc_t_is_internal(blk_qc_t cookie)
-{
-	return (cookie & BLK_QC_T_INTERNAL) != 0;
-}
-
-struct blk_rq_stat {
-	s64 mean;
-	u64 min;
-	u64 max;
-	s32 nr_samples;
-	s32 nr_batch;
-	u64 batch;
-};
-
-#endif /* __LINUX_BLK_TYPES_H */
diff --git a/include/linux/swap.h b/include/linux/swap.h
index ba5882419a7d..d5664c7d7d93 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -328,7 +328,7 @@ extern void kswapd_stop(int nid);
 
 #ifdef CONFIG_SWAP
 
-#include <linux/blk_types.h> /* for bio_end_io_t */
+#include <linux/bio.h> /* for bio_end_io_t */
 
 /* linux/mm/page_io.c */
 extern int swap_readpage(struct page *);
-- 
2.11.0

Re: [PATCH 12/15] block: merge blk_types.h into bio.h

[Bart Van Assche]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="utf-8", Size: 626 bytes --]

On Thu, 2017-05-18 at 15:18 +0200, Christoph Hellwig wrote:
> We've cleaned up our headers sufficiently that we don't need this split
> anymore.

Hello Christoph,

Request-based drivers need the structure definitions from <linux/blkdev.h> and
the type definitions from <linux/blk_types.h> but do not need the definition of
struct bio. Have you considered to remove #include <linux/bio.h> from file
include/linux/blkdev.h? Do you think that would help to reduce the kernel build
time?

Thanks,

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Re: [PATCH 12/15] block: merge blk_types.h into bio.h

[hch]

On Thu, May 18, 2017 at 02:25:52PM +0000, Bart Van Assche wrote:
> On Thu, 2017-05-18 at 15:18 +0200, Christoph Hellwig wrote:
> > We've cleaned up our headers sufficiently that we don't need this split
> > anymore.
> 
> Hello Christoph,
> 
> Request-based drivers need the structure definitions from <linux/blkdev.h> and
> the type definitions from <linux/blk_types.h> but do not need the definition of
> struct bio. Have you considered to remove #include <linux/bio.h> from file
> include/linux/blkdev.h? Do you think that would help to reduce the kernel build
> time?

Most block drivers end up needing bio.h anyway.  But I can skip this
part of the series for now.

[PATCH 14/15] blk-mq: switch ->queue_rq return value to blk_status_t

[Christoph Hellwig]

Use the same values for use for request completion errors as the return
value from ->queue_rq.  BLK_STS_RESOURCE is special cased to cause
a requeue, and all the others are completed as-is.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-mq.c                    | 37 ++++++++++++++++------------------
 drivers/block/loop.c              |  6 +++---
 drivers/block/mtip32xx/mtip32xx.c | 17 ++++++++--------
 drivers/block/nbd.c               | 12 ++++-------
 drivers/block/null_blk.c          |  4 ++--
 drivers/block/rbd.c               |  4 ++--
 drivers/block/virtio_blk.c        | 10 +++++-----
 drivers/block/xen-blkfront.c      |  8 ++++----
 drivers/md/dm-rq.c                |  8 ++++----
 drivers/mtd/ubi/block.c           |  6 +++---
 drivers/nvme/host/core.c          | 14 ++++++-------
 drivers/nvme/host/fc.c            | 23 +++++++++++----------
 drivers/nvme/host/nvme.h          |  2 +-
 drivers/nvme/host/pci.c           | 42 +++++++++++++++++++--------------------
 drivers/nvme/host/rdma.c          | 26 +++++++++++++-----------
 drivers/nvme/target/loop.c        | 17 ++++++++--------
 drivers/scsi/scsi_lib.c           | 30 ++++++++++++++--------------
 include/linux/blk-mq.h            |  7 ++-----
 18 files changed, 131 insertions(+), 142 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 1430939ecc0e..fdaad9fbebf6 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -987,7 +987,7 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list)
 {
 	struct blk_mq_hw_ctx *hctx;
 	struct request *rq;
-	int errors, queued, ret = BLK_MQ_RQ_QUEUE_OK;
+	int errors, queued;
 
 	if (list_empty(list))
 		return false;
@@ -998,6 +998,7 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list)
 	errors = queued = 0;
 	do {
 		struct blk_mq_queue_data bd;
+		blk_status_t ret;
 
 		rq = list_first_entry(list, struct request, queuelist);
 		if (!blk_mq_get_driver_tag(rq, &hctx, false)) {
@@ -1038,25 +1039,20 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list)
 		}
 
 		ret = q->mq_ops->queue_rq(hctx, &bd);
-		switch (ret) {
-		case BLK_MQ_RQ_QUEUE_OK:
-			queued++;
-			break;
-		case BLK_MQ_RQ_QUEUE_BUSY:
+		if (ret == BLK_STS_RESOURCE) {
 			blk_mq_put_driver_tag_hctx(hctx, rq);
 			list_add(&rq->queuelist, list);
 			__blk_mq_requeue_request(rq);
 			break;
-		default:
-			pr_err("blk-mq: bad return on queue: %d\n", ret);
-		case BLK_MQ_RQ_QUEUE_ERROR:
+		}
+
+		if (unlikely(ret != BLK_STS_OK)) {
 			errors++;
 			blk_mq_end_request(rq, BLK_STS_IOERR);
-			break;
+			continue;
 		}
 
-		if (ret == BLK_MQ_RQ_QUEUE_BUSY)
-			break;
+		queued++;
 	} while (!list_empty(list));
 
 	hctx->dispatched[queued_to_index(queued)]++;
@@ -1094,7 +1090,7 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list)
 		 * - blk_mq_run_hw_queue() checks whether or not a queue has
 		 *   been stopped before rerunning a queue.
 		 * - Some but not all block drivers stop a queue before
-		 *   returning BLK_MQ_RQ_QUEUE_BUSY. Two exceptions are scsi-mq
+		 *   returning BLK_STS_RESOURCE. Two exceptions are scsi-mq
 		 *   and dm-rq.
 		 */
 		if (!blk_mq_sched_needs_restart(hctx) &&
@@ -1490,7 +1486,7 @@ static void __blk_mq_try_issue_directly(struct request *rq, blk_qc_t *cookie,
 	};
 	struct blk_mq_hw_ctx *hctx;
 	blk_qc_t new_cookie;
-	int ret;
+	blk_status_t ret;
 
 	if (q->elevator)
 		goto insert;
@@ -1506,18 +1502,19 @@ static void __blk_mq_try_issue_directly(struct request *rq, blk_qc_t *cookie,
 	 * would have done
 	 */
 	ret = q->mq_ops->queue_rq(hctx, &bd);
-	if (ret == BLK_MQ_RQ_QUEUE_OK) {
+	switch (ret) {
+	case BLK_STS_OK:
 		*cookie = new_cookie;
 		return;
-	}
-
-	if (ret == BLK_MQ_RQ_QUEUE_ERROR) {
+	case BLK_STS_RESOURCE:
+		__blk_mq_requeue_request(rq);
+		goto insert;
+	default:
 		*cookie = BLK_QC_T_NONE;
-		blk_mq_end_request(rq, BLK_STS_IOERR);
+		blk_mq_end_request(rq, ret);
 		return;
 	}
 
-	__blk_mq_requeue_request(rq);
 insert:
 	blk_mq_sched_insert_request(rq, false, true, false, may_sleep);
 }
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 183597053ce5..6506412a6498 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1642,7 +1642,7 @@ int loop_unregister_transfer(int number)
 EXPORT_SYMBOL(loop_register_transfer);
 EXPORT_SYMBOL(loop_unregister_transfer);
 
-static int loop_queue_rq(struct blk_mq_hw_ctx *hctx,
+static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx,
 		const struct blk_mq_queue_data *bd)
 {
 	struct loop_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
@@ -1651,7 +1651,7 @@ static int loop_queue_rq(struct blk_mq_hw_ctx *hctx,
 	blk_mq_start_request(bd->rq);
 
 	if (lo->lo_state != Lo_bound)
-		return BLK_MQ_RQ_QUEUE_ERROR;
+		return BLK_STS_IOERR;
 
 	switch (req_op(cmd->rq)) {
 	case REQ_OP_FLUSH:
@@ -1666,7 +1666,7 @@ static int loop_queue_rq(struct blk_mq_hw_ctx *hctx,
 
 	kthread_queue_work(&lo->worker, &cmd->work);
 
-	return BLK_MQ_RQ_QUEUE_OK;
+	return BLK_STS_OK;
 }
 
 static void loop_handle_cmd(struct loop_cmd *cmd)
diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
index ee6f66bb50c7..d8618a71da74 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -3633,8 +3633,8 @@ static bool mtip_check_unal_depth(struct blk_mq_hw_ctx *hctx,
 	return false;
 }
 
-static int mtip_issue_reserved_cmd(struct blk_mq_hw_ctx *hctx,
-				   struct request *rq)
+static blk_status_t mtip_issue_reserved_cmd(struct blk_mq_hw_ctx *hctx,
+		struct request *rq)
 {
 	struct driver_data *dd = hctx->queue->queuedata;
 	struct mtip_int_cmd *icmd = rq->special;
@@ -3642,7 +3642,7 @@ static int mtip_issue_reserved_cmd(struct blk_mq_hw_ctx *hctx,
 	struct mtip_cmd_sg *command_sg;
 
 	if (mtip_commands_active(dd->port))
-		return BLK_MQ_RQ_QUEUE_BUSY;
+		return BLK_STS_RESOURCE;
 
 	/* Populate the SG list */
 	cmd->command_header->opts =
@@ -3666,10 +3666,10 @@ static int mtip_issue_reserved_cmd(struct blk_mq_hw_ctx *hctx,
 
 	blk_mq_start_request(rq);
 	mtip_issue_non_ncq_command(dd->port, rq->tag);
-	return BLK_MQ_RQ_QUEUE_OK;
+	return 0;
 }
 
-static int mtip_queue_rq(struct blk_mq_hw_ctx *hctx,
+static blk_status_t mtip_queue_rq(struct blk_mq_hw_ctx *hctx,
 			 const struct blk_mq_queue_data *bd)
 {
 	struct request *rq = bd->rq;
@@ -3681,15 +3681,14 @@ static int mtip_queue_rq(struct blk_mq_hw_ctx *hctx,
 		return mtip_issue_reserved_cmd(hctx, rq);
 
 	if (unlikely(mtip_check_unal_depth(hctx, rq)))
-		return BLK_MQ_RQ_QUEUE_BUSY;
+		return BLK_STS_RESOURCE;
 
 	blk_mq_start_request(rq);
 
 	ret = mtip_submit_request(hctx, rq);
 	if (likely(!ret))
-		return BLK_MQ_RQ_QUEUE_OK;
-
-	return BLK_MQ_RQ_QUEUE_ERROR;
+		return BLK_STS_OK;
+	return BLK_STS_IOERR;
 }
 
 static void mtip_free_cmd(struct blk_mq_tag_set *set, struct request *rq,
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 9f5a0d4fcf81..789e36ee6844 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -465,7 +465,7 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
 				nsock->pending = req;
 				nsock->sent = sent;
 			}
-			return BLK_MQ_RQ_QUEUE_BUSY;
+			return BLK_STS_RESOURCE;
 		}
 		dev_err_ratelimited(disk_to_dev(nbd->disk),
 			"Send control failed (result %d)\n", result);
@@ -506,7 +506,7 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
 					 */
 					nsock->pending = req;
 					nsock->sent = sent;
-					return BLK_MQ_RQ_QUEUE_BUSY;
+					return BLK_STS_RESOURCE;
 				}
 				dev_err(disk_to_dev(nbd->disk),
 					"Send data failed (result %d)\n",
@@ -794,7 +794,7 @@ static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)
 	return ret;
 }
 
-static int nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
+static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
 			const struct blk_mq_queue_data *bd)
 {
 	struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
@@ -818,13 +818,9 @@ static int nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
 	 * appropriate.
 	 */
 	ret = nbd_handle_cmd(cmd, hctx->queue_num);
-	if (ret < 0)
-		ret = BLK_MQ_RQ_QUEUE_ERROR;
-	if (!ret)
-		ret = BLK_MQ_RQ_QUEUE_OK;
 	complete(&cmd->send_complete);
 
-	return ret;
+	return ret < 0 ? BLK_STS_IOERR : BLK_STS_OK;
 }
 
 static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
index e6b81d370882..586dfff5d53f 100644
--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -356,7 +356,7 @@ static void null_request_fn(struct request_queue *q)
 	}
 }
 
-static int null_queue_rq(struct blk_mq_hw_ctx *hctx,
+static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx,
 			 const struct blk_mq_queue_data *bd)
 {
 	struct nullb_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
@@ -373,7 +373,7 @@ static int null_queue_rq(struct blk_mq_hw_ctx *hctx,
 	blk_mq_start_request(bd->rq);
 
 	null_handle_cmd(cmd);
-	return BLK_MQ_RQ_QUEUE_OK;
+	return BLK_STS_OK;
 }
 
 static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq)
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 3e8b43d792c2..74a6791b15c8 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -4154,14 +4154,14 @@ static void rbd_queue_workfn(struct work_struct *work)
 	blk_mq_end_request(rq, errno_to_blk_status(result));
 }
 
-static int rbd_queue_rq(struct blk_mq_hw_ctx *hctx,
+static blk_status_t rbd_queue_rq(struct blk_mq_hw_ctx *hctx,
 		const struct blk_mq_queue_data *bd)
 {
 	struct request *rq = bd->rq;
 	struct work_struct *work = blk_mq_rq_to_pdu(rq);
 
 	queue_work(rbd_wq, work);
-	return BLK_MQ_RQ_QUEUE_OK;
+	return BLK_STS_OK;
 }
 
 static void rbd_free_disk(struct rbd_device *rbd_dev)
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 205b74d70efc..e59bd4549a8a 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -214,7 +214,7 @@ 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,
+static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx,
 			   const struct blk_mq_queue_data *bd)
 {
 	struct virtio_blk *vblk = hctx->queue->queuedata;
@@ -246,7 +246,7 @@ static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx,
 		break;
 	default:
 		WARN_ON_ONCE(1);
-		return BLK_MQ_RQ_QUEUE_ERROR;
+		return BLK_STS_IOERR;
 	}
 
 	vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, type);
@@ -276,8 +276,8 @@ static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx,
 		/* Out of mem doesn't actually happen, since we fall back
 		 * to direct descriptors */
 		if (err == -ENOMEM || err == -ENOSPC)
-			return BLK_MQ_RQ_QUEUE_BUSY;
-		return BLK_MQ_RQ_QUEUE_ERROR;
+			return BLK_STS_RESOURCE;
+		return BLK_STS_IOERR;
 	}
 
 	if (bd->last && virtqueue_kick_prepare(vblk->vqs[qid].vq))
@@ -286,7 +286,7 @@ static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx,
 
 	if (notify)
 		virtqueue_notify(vblk->vqs[qid].vq);
-	return BLK_MQ_RQ_QUEUE_OK;
+	return BLK_STS_OK;
 }
 
 /* return id (s/n) string for *disk to *id_str
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index aedc3c759273..2f468cf86dcf 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -881,7 +881,7 @@ static inline bool blkif_request_flush_invalid(struct request *req,
 		 !info->feature_fua));
 }
 
-static int blkif_queue_rq(struct blk_mq_hw_ctx *hctx,
+static blk_status_t blkif_queue_rq(struct blk_mq_hw_ctx *hctx,
 			  const struct blk_mq_queue_data *qd)
 {
 	unsigned long flags;
@@ -904,16 +904,16 @@ static int blkif_queue_rq(struct blk_mq_hw_ctx *hctx,
 
 	flush_requests(rinfo);
 	spin_unlock_irqrestore(&rinfo->ring_lock, flags);
-	return BLK_MQ_RQ_QUEUE_OK;
+	return BLK_STS_OK;
 
 out_err:
 	spin_unlock_irqrestore(&rinfo->ring_lock, flags);
-	return BLK_MQ_RQ_QUEUE_ERROR;
+	return BLK_STS_IOERR;
 
 out_busy:
 	spin_unlock_irqrestore(&rinfo->ring_lock, flags);
 	blk_mq_stop_hw_queue(hctx);
-	return BLK_MQ_RQ_QUEUE_BUSY;
+	return BLK_STS_RESOURCE;
 }
 
 static void blkif_complete_rq(struct request *rq)
diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
index bee334389173..63402f8a38de 100644
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -727,7 +727,7 @@ static int dm_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
 	return __dm_rq_init_rq(set->driver_data, rq);
 }
 
-static int dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
+static blk_status_t dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
 			  const struct blk_mq_queue_data *bd)
 {
 	struct request *rq = bd->rq;
@@ -744,7 +744,7 @@ static int dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
 	}
 
 	if (ti->type->busy && ti->type->busy(ti))
-		return BLK_MQ_RQ_QUEUE_BUSY;
+		return BLK_STS_RESOURCE;
 
 	dm_start_request(md, rq);
 
@@ -762,10 +762,10 @@ static int dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
 		rq_end_stats(md, rq);
 		rq_completed(md, rq_data_dir(rq), false);
 		blk_mq_delay_run_hw_queue(hctx, 100/*ms*/);
-		return BLK_MQ_RQ_QUEUE_BUSY;
+		return BLK_STS_RESOURCE;
 	}
 
-	return BLK_MQ_RQ_QUEUE_OK;
+	return BLK_STS_OK;
 }
 
 static const struct blk_mq_ops dm_mq_ops = {
diff --git a/drivers/mtd/ubi/block.c b/drivers/mtd/ubi/block.c
index 3ecdb39d1985..c3963f880448 100644
--- a/drivers/mtd/ubi/block.c
+++ b/drivers/mtd/ubi/block.c
@@ -316,7 +316,7 @@ static void ubiblock_do_work(struct work_struct *work)
 	blk_mq_end_request(req, errno_to_blk_status(ret));
 }
 
-static int ubiblock_queue_rq(struct blk_mq_hw_ctx *hctx,
+static blk_status_t ubiblock_queue_rq(struct blk_mq_hw_ctx *hctx,
 			     const struct blk_mq_queue_data *bd)
 {
 	struct request *req = bd->rq;
@@ -327,9 +327,9 @@ static int ubiblock_queue_rq(struct blk_mq_hw_ctx *hctx,
 	case REQ_OP_READ:
 		ubi_sgl_init(&pdu->usgl);
 		queue_work(dev->wq, &pdu->work);
-		return BLK_MQ_RQ_QUEUE_OK;
+		return BLK_STS_OK;
 	default:
-		return BLK_MQ_RQ_QUEUE_ERROR;
+		return BLK_STS_IOERR;
 	}
 
 }
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 98fb0470d693..bac931f629ba 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -283,7 +283,7 @@ static inline void nvme_setup_flush(struct nvme_ns *ns,
 	cmnd->common.nsid = cpu_to_le32(ns->ns_id);
 }
 
-static inline int nvme_setup_discard(struct nvme_ns *ns, struct request *req,
+static blk_status_t nvme_setup_discard(struct nvme_ns *ns, struct request *req,
 		struct nvme_command *cmnd)
 {
 	unsigned short segments = blk_rq_nr_discard_segments(req), n = 0;
@@ -292,7 +292,7 @@ static inline int nvme_setup_discard(struct nvme_ns *ns, struct request *req,
 
 	range = kmalloc_array(segments, sizeof(*range), GFP_ATOMIC);
 	if (!range)
-		return BLK_MQ_RQ_QUEUE_BUSY;
+		return BLK_STS_RESOURCE;
 
 	__rq_for_each_bio(bio, req) {
 		u64 slba = nvme_block_nr(ns, bio->bi_iter.bi_sector);
@@ -306,7 +306,7 @@ static inline int nvme_setup_discard(struct nvme_ns *ns, struct request *req,
 
 	if (WARN_ON_ONCE(n != segments)) {
 		kfree(range);
-		return BLK_MQ_RQ_QUEUE_ERROR;
+		return BLK_STS_IOERR;
 	}
 
 	memset(cmnd, 0, sizeof(*cmnd));
@@ -320,7 +320,7 @@ static inline int nvme_setup_discard(struct nvme_ns *ns, struct request *req,
 	req->special_vec.bv_len = sizeof(*range) * segments;
 	req->rq_flags |= RQF_SPECIAL_PAYLOAD;
 
-	return BLK_MQ_RQ_QUEUE_OK;
+	return BLK_STS_OK;
 }
 
 static inline void nvme_setup_rw(struct nvme_ns *ns, struct request *req,
@@ -364,10 +364,10 @@ static inline void nvme_setup_rw(struct nvme_ns *ns, struct request *req,
 	cmnd->rw.dsmgmt = cpu_to_le32(dsmgmt);
 }
 
-int nvme_setup_cmd(struct nvme_ns *ns, struct request *req,
+blk_status_t nvme_setup_cmd(struct nvme_ns *ns, struct request *req,
 		struct nvme_command *cmd)
 {
-	int ret = BLK_MQ_RQ_QUEUE_OK;
+	blk_status_t ret = BLK_STS_OK;
 
 	if (!(req->rq_flags & RQF_DONTPREP)) {
 		nvme_req(req)->retries = 0;
@@ -394,7 +394,7 @@ int nvme_setup_cmd(struct nvme_ns *ns, struct request *req,
 		break;
 	default:
 		WARN_ON_ONCE(1);
-		return BLK_MQ_RQ_QUEUE_ERROR;
+		return BLK_STS_IOERR;
 	}
 
 	cmd->common.command_id = req->tag;
diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index 70e689bf1cad..8443d03e3a04 100644
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -1873,7 +1873,7 @@ nvme_fc_unmap_data(struct nvme_fc_ctrl *ctrl, struct request *rq,
  * level FC exchange resource that is also outstanding. This must be
  * considered in all cleanup operations.
  */
-static int
+static blk_status_t
 nvme_fc_start_fcp_op(struct nvme_fc_ctrl *ctrl, struct nvme_fc_queue *queue,
 	struct nvme_fc_fcp_op *op, u32 data_len,
 	enum nvmefc_fcp_datadir	io_dir)
@@ -1888,10 +1888,10 @@ nvme_fc_start_fcp_op(struct nvme_fc_ctrl *ctrl, struct nvme_fc_queue *queue,
 	 * the target device is present
 	 */
 	if (ctrl->rport->remoteport.port_state != FC_OBJSTATE_ONLINE)
-		return BLK_MQ_RQ_QUEUE_ERROR;
+		return BLK_STS_IOERR;
 
 	if (!nvme_fc_ctrl_get(ctrl))
-		return BLK_MQ_RQ_QUEUE_ERROR;
+		return BLK_STS_IOERR;
 
 	/* format the FC-NVME CMD IU and fcp_req */
 	cmdiu->connection_id = cpu_to_be64(queue->connection_id);
@@ -1939,8 +1939,9 @@ nvme_fc_start_fcp_op(struct nvme_fc_ctrl *ctrl, struct nvme_fc_queue *queue,
 		if (ret < 0) {
 			nvme_cleanup_cmd(op->rq);
 			nvme_fc_ctrl_put(ctrl);
-			return (ret == -ENOMEM || ret == -EAGAIN) ?
-				BLK_MQ_RQ_QUEUE_BUSY : BLK_MQ_RQ_QUEUE_ERROR;
+			if (ret == -ENOMEM || ret == -EAGAIN)
+				return BLK_STS_RESOURCE;
+			return BLK_STS_IOERR;
 		}
 	}
 
@@ -1966,19 +1967,19 @@ nvme_fc_start_fcp_op(struct nvme_fc_ctrl *ctrl, struct nvme_fc_queue *queue,
 		nvme_fc_ctrl_put(ctrl);
 
 		if (ret != -EBUSY)
-			return BLK_MQ_RQ_QUEUE_ERROR;
+			return BLK_STS_IOERR;
 
 		if (op->rq) {
 			blk_mq_stop_hw_queues(op->rq->q);
 			blk_mq_delay_queue(queue->hctx, NVMEFC_QUEUE_DELAY);
 		}
-		return BLK_MQ_RQ_QUEUE_BUSY;
+		return BLK_STS_RESOURCE;
 	}
 
-	return BLK_MQ_RQ_QUEUE_OK;
+	return BLK_STS_OK;
 }
 
-static int
+static blk_status_t
 nvme_fc_queue_rq(struct blk_mq_hw_ctx *hctx,
 			const struct blk_mq_queue_data *bd)
 {
@@ -1991,7 +1992,7 @@ nvme_fc_queue_rq(struct blk_mq_hw_ctx *hctx,
 	struct nvme_command *sqe = &cmdiu->sqe;
 	enum nvmefc_fcp_datadir	io_dir;
 	u32 data_len;
-	int ret;
+	blk_status_t ret;
 
 	ret = nvme_setup_cmd(ns, rq, sqe);
 	if (ret)
@@ -2046,7 +2047,7 @@ nvme_fc_submit_async_event(struct nvme_ctrl *arg, int aer_idx)
 	struct nvme_fc_fcp_op *aen_op;
 	unsigned long flags;
 	bool terminating = false;
-	int ret;
+	blk_status_t ret;
 
 	if (aer_idx > NVME_FC_NR_AEN_COMMANDS)
 		return;
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 29c708ca9621..3ba5157b0738 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -294,7 +294,7 @@ void nvme_start_freeze(struct nvme_ctrl *ctrl);
 #define NVME_QID_ANY -1
 struct request *nvme_alloc_request(struct request_queue *q,
 		struct nvme_command *cmd, unsigned int flags, int qid);
-int nvme_setup_cmd(struct nvme_ns *ns, struct request *req,
+blk_status_t nvme_setup_cmd(struct nvme_ns *ns, struct request *req,
 		struct nvme_command *cmd);
 int nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
 		void *buf, unsigned bufflen);
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index dc66b035a220..89427606e8b9 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -427,7 +427,7 @@ static __le64 **iod_list(struct request *req)
 	return (__le64 **)(iod->sg + blk_rq_nr_phys_segments(req));
 }
 
-static int nvme_init_iod(struct request *rq, struct nvme_dev *dev)
+static blk_status_t nvme_init_iod(struct request *rq, struct nvme_dev *dev)
 {
 	struct nvme_iod *iod = blk_mq_rq_to_pdu(rq);
 	int nseg = blk_rq_nr_phys_segments(rq);
@@ -436,7 +436,7 @@ static int nvme_init_iod(struct request *rq, struct nvme_dev *dev)
 	if (nseg > NVME_INT_PAGES || size > NVME_INT_BYTES(dev)) {
 		iod->sg = kmalloc(nvme_iod_alloc_size(dev, size, nseg), GFP_ATOMIC);
 		if (!iod->sg)
-			return BLK_MQ_RQ_QUEUE_BUSY;
+			return BLK_STS_RESOURCE;
 	} else {
 		iod->sg = iod->inline_sg;
 	}
@@ -446,7 +446,7 @@ static int nvme_init_iod(struct request *rq, struct nvme_dev *dev)
 	iod->nents = 0;
 	iod->length = size;
 
-	return BLK_MQ_RQ_QUEUE_OK;
+	return BLK_STS_OK;
 }
 
 static void nvme_free_iod(struct nvme_dev *dev, struct request *req)
@@ -616,21 +616,21 @@ static bool nvme_setup_prps(struct nvme_dev *dev, struct request *req)
 	return true;
 }
 
-static int nvme_map_data(struct nvme_dev *dev, struct request *req,
+static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
 		struct nvme_command *cmnd)
 {
 	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
 	struct request_queue *q = req->q;
 	enum dma_data_direction dma_dir = rq_data_dir(req) ?
 			DMA_TO_DEVICE : DMA_FROM_DEVICE;
-	int ret = BLK_MQ_RQ_QUEUE_ERROR;
+	blk_status_t ret = BLK_STS_IOERR;
 
 	sg_init_table(iod->sg, blk_rq_nr_phys_segments(req));
 	iod->nents = blk_rq_map_sg(q, req, iod->sg);
 	if (!iod->nents)
 		goto out;
 
-	ret = BLK_MQ_RQ_QUEUE_BUSY;
+	ret = BLK_STS_RESOURCE;
 	if (!dma_map_sg_attrs(dev->dev, iod->sg, iod->nents, dma_dir,
 				DMA_ATTR_NO_WARN))
 		goto out;
@@ -638,7 +638,7 @@ static int nvme_map_data(struct nvme_dev *dev, struct request *req,
 	if (!nvme_setup_prps(dev, req))
 		goto out_unmap;
 
-	ret = BLK_MQ_RQ_QUEUE_ERROR;
+	ret = BLK_STS_IOERR;
 	if (blk_integrity_rq(req)) {
 		if (blk_rq_count_integrity_sg(q, req->bio) != 1)
 			goto out_unmap;
@@ -658,7 +658,7 @@ static int nvme_map_data(struct nvme_dev *dev, struct request *req,
 	cmnd->rw.dptr.prp2 = cpu_to_le64(iod->first_dma);
 	if (blk_integrity_rq(req))
 		cmnd->rw.metadata = cpu_to_le64(sg_dma_address(&iod->meta_sg));
-	return BLK_MQ_RQ_QUEUE_OK;
+	return BLK_STS_OK;
 
 out_unmap:
 	dma_unmap_sg(dev->dev, iod->sg, iod->nents, dma_dir);
@@ -688,7 +688,7 @@ static void nvme_unmap_data(struct nvme_dev *dev, struct request *req)
 /*
  * NOTE: ns is NULL when called on the admin queue.
  */
-static int nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
+static blk_status_t nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
 			 const struct blk_mq_queue_data *bd)
 {
 	struct nvme_ns *ns = hctx->queue->queuedata;
@@ -696,7 +696,7 @@ static int nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
 	struct nvme_dev *dev = nvmeq->dev;
 	struct request *req = bd->rq;
 	struct nvme_command cmnd;
-	int ret = BLK_MQ_RQ_QUEUE_OK;
+	blk_status_t ret = BLK_STS_OK;
 
 	/*
 	 * If formated with metadata, require the block layer provide a buffer
@@ -705,38 +705,36 @@ static int nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
 	 */
 	if (ns && ns->ms && !blk_integrity_rq(req)) {
 		if (!(ns->pi_type && ns->ms == 8) &&
-		    !blk_rq_is_passthrough(req)) {
-			blk_mq_end_request(req, BLK_STS_NOTSUPP);
-			return BLK_MQ_RQ_QUEUE_OK;
-		}
+		    !blk_rq_is_passthrough(req))
+			return BLK_STS_NOTSUPP;
 	}
 
 	ret = nvme_setup_cmd(ns, req, &cmnd);
-	if (ret != BLK_MQ_RQ_QUEUE_OK)
+	if (ret)
 		return ret;
 
 	ret = nvme_init_iod(req, dev);
-	if (ret != BLK_MQ_RQ_QUEUE_OK)
+	if (ret)
 		goto out_free_cmd;
 
-	if (blk_rq_nr_phys_segments(req))
+	if (blk_rq_nr_phys_segments(req)) {
 		ret = nvme_map_data(dev, req, &cmnd);
-
-	if (ret != BLK_MQ_RQ_QUEUE_OK)
-		goto out_cleanup_iod;
+		if (ret)
+			goto out_cleanup_iod;
+	}
 
 	blk_mq_start_request(req);
 
 	spin_lock_irq(&nvmeq->q_lock);
 	if (unlikely(nvmeq->cq_vector < 0)) {
-		ret = BLK_MQ_RQ_QUEUE_ERROR;
+		ret = BLK_STS_IOERR;
 		spin_unlock_irq(&nvmeq->q_lock);
 		goto out_cleanup_iod;
 	}
 	__nvme_submit_cmd(nvmeq, &cmnd);
 	nvme_process_cq(nvmeq);
 	spin_unlock_irq(&nvmeq->q_lock);
-	return BLK_MQ_RQ_QUEUE_OK;
+	return BLK_STS_OK;
 out_cleanup_iod:
 	nvme_free_iod(dev, req);
 out_free_cmd:
diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index dd1c6deef82f..073d58065b00 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -1438,7 +1438,7 @@ static inline bool nvme_rdma_queue_is_ready(struct nvme_rdma_queue *queue,
 	return true;
 }
 
-static int nvme_rdma_queue_rq(struct blk_mq_hw_ctx *hctx,
+static blk_status_t nvme_rdma_queue_rq(struct blk_mq_hw_ctx *hctx,
 		const struct blk_mq_queue_data *bd)
 {
 	struct nvme_ns *ns = hctx->queue->queuedata;
@@ -1449,27 +1449,28 @@ static int nvme_rdma_queue_rq(struct blk_mq_hw_ctx *hctx,
 	struct nvme_command *c = sqe->data;
 	bool flush = false;
 	struct ib_device *dev;
-	int ret;
+	blk_status_t ret;
+	int err;
 
 	WARN_ON_ONCE(rq->tag < 0);
 
 	if (!nvme_rdma_queue_is_ready(queue, rq))
-		return BLK_MQ_RQ_QUEUE_BUSY;
+		return BLK_STS_RESOURCE;
 
 	dev = queue->device->dev;
 	ib_dma_sync_single_for_cpu(dev, sqe->dma,
 			sizeof(struct nvme_command), DMA_TO_DEVICE);
 
 	ret = nvme_setup_cmd(ns, rq, c);
-	if (ret != BLK_MQ_RQ_QUEUE_OK)
+	if (ret)
 		return ret;
 
 	blk_mq_start_request(rq);
 
-	ret = nvme_rdma_map_data(queue, rq, c);
-	if (ret < 0) {
+	err = nvme_rdma_map_data(queue, rq, c);
+	if (err < 0) {
 		dev_err(queue->ctrl->ctrl.device,
-			     "Failed to map data (%d)\n", ret);
+			     "Failed to map data (%d)\n", err);
 		nvme_cleanup_cmd(rq);
 		goto err;
 	}
@@ -1479,17 +1480,18 @@ static int nvme_rdma_queue_rq(struct blk_mq_hw_ctx *hctx,
 
 	if (req_op(rq) == REQ_OP_FLUSH)
 		flush = true;
-	ret = nvme_rdma_post_send(queue, sqe, req->sge, req->num_sge,
+	err = nvme_rdma_post_send(queue, sqe, req->sge, req->num_sge,
 			req->mr->need_inval ? &req->reg_wr.wr : NULL, flush);
-	if (ret) {
+	if (err) {
 		nvme_rdma_unmap_data(queue, rq);
 		goto err;
 	}
 
-	return BLK_MQ_RQ_QUEUE_OK;
+	return BLK_STS_OK;
 err:
-	return (ret == -ENOMEM || ret == -EAGAIN) ?
-		BLK_MQ_RQ_QUEUE_BUSY : BLK_MQ_RQ_QUEUE_ERROR;
+	if (err == -ENOMEM || err == -EAGAIN)
+		return BLK_STS_RESOURCE;
+	return BLK_STS_IOERR;
 }
 
 static int nvme_rdma_poll(struct blk_mq_hw_ctx *hctx, unsigned int tag)
diff --git a/drivers/nvme/target/loop.c b/drivers/nvme/target/loop.c
index feb497134aee..948b817fcd76 100644
--- a/drivers/nvme/target/loop.c
+++ b/drivers/nvme/target/loop.c
@@ -159,17 +159,17 @@ nvme_loop_timeout(struct request *rq, bool reserved)
 	return BLK_EH_HANDLED;
 }
 
-static int nvme_loop_queue_rq(struct blk_mq_hw_ctx *hctx,
+static blk_status_t nvme_loop_queue_rq(struct blk_mq_hw_ctx *hctx,
 		const struct blk_mq_queue_data *bd)
 {
 	struct nvme_ns *ns = hctx->queue->queuedata;
 	struct nvme_loop_queue *queue = hctx->driver_data;
 	struct request *req = bd->rq;
 	struct nvme_loop_iod *iod = blk_mq_rq_to_pdu(req);
-	int ret;
+	blk_status_t ret;
 
 	ret = nvme_setup_cmd(ns, req, &iod->cmd);
-	if (ret != BLK_MQ_RQ_QUEUE_OK)
+	if (ret)
 		return ret;
 
 	iod->cmd.common.flags |= NVME_CMD_SGL_METABUF;
@@ -179,16 +179,15 @@ static int nvme_loop_queue_rq(struct blk_mq_hw_ctx *hctx,
 		nvme_cleanup_cmd(req);
 		blk_mq_start_request(req);
 		nvme_loop_queue_response(&iod->req);
-		return BLK_MQ_RQ_QUEUE_OK;
+		return BLK_STS_OK;
 	}
 
 	if (blk_rq_bytes(req)) {
 		iod->sg_table.sgl = iod->first_sgl;
-		ret = sg_alloc_table_chained(&iod->sg_table,
+		if (sg_alloc_table_chained(&iod->sg_table,
 				blk_rq_nr_phys_segments(req),
-				iod->sg_table.sgl);
-		if (ret)
-			return BLK_MQ_RQ_QUEUE_BUSY;
+				iod->sg_table.sgl))
+			return BLK_STS_RESOURCE;
 
 		iod->req.sg = iod->sg_table.sgl;
 		iod->req.sg_cnt = blk_rq_map_sg(req->q, req, iod->sg_table.sgl);
@@ -197,7 +196,7 @@ static int nvme_loop_queue_rq(struct blk_mq_hw_ctx *hctx,
 	blk_mq_start_request(req);
 
 	schedule_work(&iod->work);
-	return BLK_MQ_RQ_QUEUE_OK;
+	return BLK_STS_OK;
 }
 
 static void nvme_loop_submit_async_event(struct nvme_ctrl *arg, int aer_idx)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 8c2cf11c126b..88b2d18f2ee5 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1811,15 +1811,15 @@ static void scsi_request_fn(struct request_queue *q)
 		blk_delay_queue(q, SCSI_QUEUE_DELAY);
 }
 
-static inline int prep_to_mq(int ret)
+static inline blk_status_t prep_to_mq(int ret)
 {
 	switch (ret) {
 	case BLKPREP_OK:
-		return BLK_MQ_RQ_QUEUE_OK;
+		return BLK_STS_OK;
 	case BLKPREP_DEFER:
-		return BLK_MQ_RQ_QUEUE_BUSY;
+		return BLK_STS_RESOURCE;
 	default:
-		return BLK_MQ_RQ_QUEUE_ERROR;
+		return BLK_STS_IOERR;
 	}
 }
 
@@ -1891,7 +1891,7 @@ 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,
+static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
 			 const struct blk_mq_queue_data *bd)
 {
 	struct request *req = bd->rq;
@@ -1899,14 +1899,14 @@ static int scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
 	struct scsi_device *sdev = q->queuedata;
 	struct Scsi_Host *shost = sdev->host;
 	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
-	int ret;
+	blk_status_t ret;
 	int reason;
 
 	ret = prep_to_mq(scsi_prep_state_check(sdev, req));
-	if (ret != BLK_MQ_RQ_QUEUE_OK)
+	if (ret != BLK_STS_OK)
 		goto out;
 
-	ret = BLK_MQ_RQ_QUEUE_BUSY;
+	ret = BLK_STS_RESOURCE;
 	if (!get_device(&sdev->sdev_gendev))
 		goto out;
 
@@ -1919,7 +1919,7 @@ static int scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
 
 	if (!(req->rq_flags & RQF_DONTPREP)) {
 		ret = prep_to_mq(scsi_mq_prep_fn(req));
-		if (ret != BLK_MQ_RQ_QUEUE_OK)
+		if (ret != BLK_STS_OK)
 			goto out_dec_host_busy;
 		req->rq_flags |= RQF_DONTPREP;
 	} else {
@@ -1937,11 +1937,11 @@ static int scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
 	reason = scsi_dispatch_cmd(cmd);
 	if (reason) {
 		scsi_set_blocked(cmd, reason);
-		ret = BLK_MQ_RQ_QUEUE_BUSY;
+		ret = BLK_STS_RESOURCE;
 		goto out_dec_host_busy;
 	}
 
-	return BLK_MQ_RQ_QUEUE_OK;
+	return BLK_STS_OK;
 
 out_dec_host_busy:
 	atomic_dec(&shost->host_busy);
@@ -1954,12 +1954,14 @@ static int scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
 	put_device(&sdev->sdev_gendev);
 out:
 	switch (ret) {
-	case BLK_MQ_RQ_QUEUE_BUSY:
+	case BLK_STS_OK:
+		break;
+	case BLK_STS_RESOURCE:
 		if (atomic_read(&sdev->device_busy) == 0 &&
 		    !scsi_device_blocked(sdev))
 			blk_mq_delay_run_hw_queue(hctx, SCSI_QUEUE_DELAY);
 		break;
-	case BLK_MQ_RQ_QUEUE_ERROR:
+	default:
 		/*
 		 * Make sure to release all allocated ressources when
 		 * we hit an error, as we will never see this command
@@ -1968,8 +1970,6 @@ static int scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
 		if (req->rq_flags & RQF_DONTPREP)
 			scsi_mq_uninit_cmd(cmd);
 		break;
-	default:
-		break;
 	}
 	return ret;
 }
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index da0e881fd0ca..9d0ef0df75a6 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -87,7 +87,8 @@ struct blk_mq_queue_data {
 	bool last;
 };
 
-typedef int (queue_rq_fn)(struct blk_mq_hw_ctx *, const struct blk_mq_queue_data *);
+typedef blk_status_t (queue_rq_fn)(struct blk_mq_hw_ctx *,
+		const struct blk_mq_queue_data *);
 typedef enum blk_eh_timer_return (timeout_fn)(struct request *, bool);
 typedef int (init_hctx_fn)(struct blk_mq_hw_ctx *, void *, unsigned int);
 typedef void (exit_hctx_fn)(struct blk_mq_hw_ctx *, unsigned int);
@@ -155,10 +156,6 @@ struct blk_mq_ops {
 };
 
 enum {
-	BLK_MQ_RQ_QUEUE_OK	= 0,	/* queued fine */
-	BLK_MQ_RQ_QUEUE_BUSY	= 1,	/* requeue IO for later */
-	BLK_MQ_RQ_QUEUE_ERROR	= 2,	/* end IO with error */
-
 	BLK_MQ_F_SHOULD_MERGE	= 1 << 0,
 	BLK_MQ_F_TAG_SHARED	= 1 << 1,
 	BLK_MQ_F_SG_MERGE	= 1 << 2,
-- 
2.11.0

Re: dedicated error codes for the block layer

[David Sterba]

On Thu, May 18, 2017 at 03:17:57PM +0200, Christoph Hellwig wrote:
> This series introduces a new blk_status_t error code type for the block
> layer so that we can have tigher control and explicit semantics for
> block layer errors.
> 
> All but the last three patches are cleanups that lead to the new type.
> 
> The series it mostly limited to the block layer and drivers, and touching
> file systems a little bit.  The only major exception is btrfs, which
> does funny things with bios and thus sees a larger amount of propagation
> of the new blk_status_t.

JFYI, the patches 13 and 15 are missing, not in linux-btrfs mailbox and
patchwork web. Does not look like a delay, maybe vger refused them
completely.

Re: dedicated error codes for the block layer

[Christoph Hellwig]

On Thu, May 18, 2017 at 04:55:08PM +0200, David Sterba wrote:
> JFYI, the patches 13 and 15 are missing, not in linux-btrfs mailbox and
> patchwork web. Does not look like a delay, maybe vger refused them
> completely.

They still haven't made it to linux-block and linux-btrfs, but they did
make it to dm-devel, which is not host on vger.

I also have a git tree here:

   git://git.infradead.org/users/hch/block.git block-errors

Gitweb:

   http://git.infradead.org/users/hch/block.git/shortlog/refs/heads/block-errors