bio-integrity: fold bio_integrity_enabled to bio_integrity_prep

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>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
[hch: merged with the latest block tree,
	return bool from bio_integrity_prep]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 39 insertions, 49 deletions

diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index 3a0d71199fb07..44c4c52681c20 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
@@ -262,14 +224,15 @@ static blk_status_t bio_integrity_process(struct bio *bio,
  * bio_integrity_prep - Prepare bio for integrity I/O
  * @bio:	bio to prepare
  *
- * Description: Allocates a buffer for integrity metadata, maps the
- * pages and attaches them to a bio.  The bio must have data
- * direction, target device and start sector set priot to calling.  In
- * the WRITE case, integrity metadata will be generated using the
- * block device's integrity function.  In the READ case, the buffer
+ * 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.
+ * The bio must have data direction, target device and start sector set priot
+ * to calling.  In the WRITE case, integrity metadata will be generated using
+ * the 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)
+bool bio_integrity_prep(struct bio *bio)
 {
 	struct bio_integrity_payload *bip;
 	struct blk_integrity *bi;
@@ -279,20 +242,41 @@ int bio_integrity_prep(struct bio *bio)
 	unsigned int len, nr_pages;
 	unsigned int bytes, offset, i;
 	unsigned int intervals;
+	blk_status_t status;
 
 	bi = bdev_get_integrity(bio->bi_bdev);
 	q = bdev_get_queue(bio->bi_bdev);
-	BUG_ON(bi == NULL);
-	BUG_ON(bio_integrity(bio));
+	if (bio_op(bio) != REQ_OP_READ && bio_op(bio) != REQ_OP_WRITE)
+		return true;
+
+	if (!bio_sectors(bio))
+		return true;
 
+	/* Already protected? */
+	if (bio_integrity(bio))
+		return true;
+
+	if (bi == NULL)
+		return true;
+
+	if (bio_data_dir(bio) == READ) {
+		if (!bi->profile->verify_fn ||
+		    !(bi->flags & BLK_INTEGRITY_VERIFY))
+			return true;
+	} else {
+		if (!bi->profile->generate_fn ||
+		    !(bi->flags & BLK_INTEGRITY_GENERATE))
+			return true;
+	}
 	intervals = bio_integrity_intervals(bi, bio_sectors(bio));
 
 	/* Allocate kernel buffer for protection data */
 	len = intervals * bi->tuple_size;
 	buf = kmalloc(len, GFP_NOIO | q->bounce_gfp);
+	status = BLK_STS_RESOURCE;
 	if (unlikely(buf == NULL)) {
 		printk(KERN_ERR "could not allocate integrity buffer\n");
-		return -ENOMEM;
+		goto err_end_io;
 	}
 
 	end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
@@ -304,7 +288,8 @@ int bio_integrity_prep(struct bio *bio)
 	if (IS_ERR(bip)) {
 		printk(KERN_ERR "could not allocate data integrity bioset\n");
 		kfree(buf);
-		return PTR_ERR(bip);
+		status = BLK_STS_RESOURCE;
+		goto err_end_io;
 	}
 
 	bip->bip_flags |= BIP_BLOCK_INTEGRITY;
@@ -349,8 +334,13 @@ int bio_integrity_prep(struct bio *bio)
 	/* Auto-generate integrity metadata if this is a write */
 	if (bio_data_dir(bio) == WRITE)
 		bio_integrity_process(bio, bi->profile->generate_fn);
+	return true;
+
+err_end_io:
+	bio->bi_status = status;
+	bio_endio(bio);
+	return false;
 
-	return 0;
 }
 EXPORT_SYMBOL(bio_integrity_prep);