[PATCH 5/9] bio-integrity: fold bio_integrity_enabled to bio_integrity_prep

[Dmitry Monakhov <dmonakhov@openvz.org>]

Currently all integrity prep hooks are open-coded, and if prepare fails
we ignore it's code and fail bio with EIO. Let's return real error to
upper layer, so later caller may react accordingly.

In fact no one want to use bio_integrity_prep() w/o bio_integrity_enabled,
so it is reasonable to fold it in to one function.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
---
 Documentation/block/data-integrity.txt |  3 --
 block/bio-integrity.c                  | 88 ++++++++++++++++++----------------
 block/blk-core.c                       |  5 +-
 block/blk-mq.c                         |  8 +---
 drivers/nvdimm/blk.c                   | 13 +----
 drivers/nvdimm/btt.c                   | 13 +----
 include/linux/bio.h                    |  6 ---
 7 files changed, 55 insertions(+), 81 deletions(-)

diff --git a/Documentation/block/data-integrity.txt b/Documentation/block/data-integrity.txt
index f56ec97..37ac837 100644
--- a/Documentation/block/data-integrity.txt
+++ b/Documentation/block/data-integrity.txt
@@ -202,9 +202,6 @@ will require extra work due to the application tag.
       added.  It is up to the caller to ensure that the bio does not
       change while I/O is in progress.
 
-      bio_integrity_prep() should only be called if
-      bio_integrity_enabled() returned 1.
-
 
 5.3 PASSING EXISTING INTEGRITY METADATA
 
diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index 6170dad..f2b9f09 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -160,44 +160,6 @@ int bio_integrity_add_page(struct bio *bio, struct page *page,
 EXPORT_SYMBOL(bio_integrity_add_page);
 
 /**
- * bio_integrity_enabled - Check whether integrity can be passed
- * @bio:	bio to check
- *
- * Description: Determines whether bio_integrity_prep() can be called
- * on this bio or not.	bio data direction and target device must be
- * set prior to calling.  The functions honors the write_generate and
- * read_verify flags in sysfs.
- */
-bool bio_integrity_enabled(struct bio *bio)
-{
-	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
-
-	if (bio_op(bio) != REQ_OP_READ && bio_op(bio) != REQ_OP_WRITE)
-		return false;
-
-	if (!bio_sectors(bio))
-		return false;
-
-	/* Already protected? */
-	if (bio_integrity(bio))
-		return false;
-
-	if (bi == NULL)
-		return false;
-
-	if (bio_data_dir(bio) == READ && bi->profile->verify_fn != NULL &&
-	    (bi->flags & BLK_INTEGRITY_VERIFY))
-		return true;
-
-	if (bio_data_dir(bio) == WRITE && bi->profile->generate_fn != NULL &&
-	    (bi->flags & BLK_INTEGRITY_GENERATE))
-		return true;
-
-	return false;
-}
-EXPORT_SYMBOL(bio_integrity_enabled);
-
-/**
  * bio_integrity_intervals - Return number of integrity intervals for a bio
  * @bi:		blk_integrity profile for device
  * @sectors:	Size of the bio in 512-byte sectors
@@ -259,7 +221,7 @@ static int bio_integrity_process(struct bio *bio,
 }
 
 /**
- * bio_integrity_prep - Prepare bio for integrity I/O
+ * bio_integrity_setup - Prepare bio for integrity I/O
  * @bio:	bio to prepare
  *
  * Description: Allocates a buffer for integrity metadata, maps the
@@ -269,7 +231,7 @@ static int bio_integrity_process(struct bio *bio,
  * block device's integrity function.  In the READ case, the buffer
  * will be prepared for DMA and a suitable end_io handler set up.
  */
-int bio_integrity_prep(struct bio *bio)
+static int bio_integrity_setup(struct bio *bio)
 {
 	struct bio_integrity_payload *bip;
 	struct blk_integrity *bi;
@@ -352,6 +314,52 @@ int bio_integrity_prep(struct bio *bio)
 
 	return 0;
 }
+/**
+ * bio_integrity_prep - Prepare bio for integrity I/O
+ * @bio:	bio to prepare
+ *
+ * Description:  Checks if the bio already has an integrity payload attached.
+ * If it does, the payload has been generated by another kernel subsystem,
+ * and we just pass it through. Otherwise allocates integrity payload.
+ */
+
+int bio_integrity_prep(struct bio *bio)
+{
+	int err;
+	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
+
+	if (bio_op(bio) != REQ_OP_READ && bio_op(bio) != REQ_OP_WRITE)
+		return 0;
+
+	if (!bio_sectors(bio))
+		return 0;
+
+	/* Already protected? */
+	if (bio_integrity(bio))
+		return 0;
+
+	if (bi == NULL)
+		return 0;
+
+	if (bio_data_dir(bio) == READ && bi->profile->verify_fn != NULL &&
+	    (bi->flags & BLK_INTEGRITY_VERIFY))
+		goto need_prep;
+
+	if (bio_data_dir(bio) == WRITE && bi->profile->generate_fn != NULL &&
+	    (bi->flags & BLK_INTEGRITY_GENERATE))
+		goto need_prep;
+
+	return 0;
+need_prep:
+	err = bio_integrity_setup(bio);
+	if (err) {
+		bio->bi_error = err;
+		bio_endio(bio);
+	}
+	return err;
+}
+
+
 EXPORT_SYMBOL(bio_integrity_prep);
 
 /**
diff --git a/block/blk-core.c b/block/blk-core.c
index d772c22..275c1e4 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1637,11 +1637,8 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
 
 	blk_queue_split(q, &bio, q->bio_split);
 
-	if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
-		bio->bi_error = -EIO;
-		bio_endio(bio);
+	if (bio_integrity_prep(bio))
 		return BLK_QC_T_NONE;
-	}
 
 	if (op_is_flush(bio->bi_opf)) {
 		spin_lock_irq(q->queue_lock);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 08a49c6..b19cd92 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1489,10 +1489,8 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
 
 	blk_queue_bounce(q, &bio);
 
-	if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
-		bio_io_error(bio);
+	if (bio_integrity_prep(bio))
 		return BLK_QC_T_NONE;
-	}
 
 	blk_queue_split(q, &bio, q->bio_split);
 
@@ -1611,10 +1609,8 @@ static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio)
 
 	blk_queue_bounce(q, &bio);
 
-	if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
-		bio_io_error(bio);
+	if (bio_integrity_prep(bio))
 		return BLK_QC_T_NONE;
-	}
 
 	blk_queue_split(q, &bio, q->bio_split);
 
diff --git a/drivers/nvdimm/blk.c b/drivers/nvdimm/blk.c
index 9faaa96..0b49336 100644
--- a/drivers/nvdimm/blk.c
+++ b/drivers/nvdimm/blk.c
@@ -179,16 +179,8 @@ static blk_qc_t nd_blk_make_request(struct request_queue *q, struct bio *bio)
 	int err = 0, rw;
 	bool do_acct;
 
-	/*
-	 * bio_integrity_enabled also checks if the bio already has an
-	 * integrity payload attached. If it does, we *don't* do a
-	 * bio_integrity_prep here - the payload has been generated by
-	 * another kernel subsystem, and we just pass it through.
-	 */
-	if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
-		bio->bi_error = -EIO;
-		goto out;
-	}
+	if (bio_integrity_prep(bio))
+		return BLK_QC_T_NONE;
 
 	bip = bio_integrity(bio);
 	nsblk = q->queuedata;
@@ -212,7 +204,6 @@ static blk_qc_t nd_blk_make_request(struct request_queue *q, struct bio *bio)
 	if (do_acct)
 		nd_iostat_end(bio, start);
 
- out:
 	bio_endio(bio);
 	return BLK_QC_T_NONE;
 }
diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
index 368795a..3d7a9fe 100644
--- a/drivers/nvdimm/btt.c
+++ b/drivers/nvdimm/btt.c
@@ -1158,16 +1158,8 @@ static blk_qc_t btt_make_request(struct request_queue *q, struct bio *bio)
 	int err = 0;
 	bool do_acct;
 
-	/*
-	 * bio_integrity_enabled also checks if the bio already has an
-	 * integrity payload attached. If it does, we *don't* do a
-	 * bio_integrity_prep here - the payload has been generated by
-	 * another kernel subsystem, and we just pass it through.
-	 */
-	if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
-		bio->bi_error = -EIO;
-		goto out;
-	}
+	if (bio_integrity_prep(bio))
+		return BLK_QC_T_NONE;
 
 	do_acct = nd_iostat_start(bio, &start);
 	bio_for_each_segment(bvec, bio, iter) {
@@ -1194,7 +1186,6 @@ static blk_qc_t btt_make_request(struct request_queue *q, struct bio *bio)
 	if (do_acct)
 		nd_iostat_end(bio, start);
 
-out:
 	bio_endio(bio);
 	return BLK_QC_T_NONE;
 }
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 7f7bf37..65445c0 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -727,7 +727,6 @@ struct biovec_slab {
 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 extern void bio_integrity_free(struct bio *);
 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
-extern bool bio_integrity_enabled(struct bio *bio);
 extern int bio_integrity_prep(struct bio *);
 extern void bio_integrity_endio(struct bio *);
 extern void bio_integrity_advance(struct bio *, unsigned int);
@@ -744,11 +743,6 @@ static inline void *bio_integrity(struct bio *bio)
 	return NULL;
 }
 
-static inline bool bio_integrity_enabled(struct bio *bio)
-{
-	return false;
-}
-
 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
 {
 	return 0;
-- 
2.9.3