[PATCH 6/6] blk-integrity: refactor various routines

["Darrick J. Wong" <darrick.wong@oracle.com>]

Refactor blk-integrity.c to avoid duplicating similar functions, and
remove all users of pi_buf, since it's really only there to handle the
(common) case where the kernel auto-generates all the PI data.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/bio-integrity.c  |  120 +++++++++++++++++++++------------------------------
 include/linux/bio.h |    2 -
 2 files changed, 49 insertions(+), 73 deletions(-)


diff --git a/fs/bio-integrity.c b/fs/bio-integrity.c
index 381ee38..3ff1572 100644
--- a/fs/bio-integrity.c
+++ b/fs/bio-integrity.c
@@ -97,8 +97,7 @@ void bio_integrity_free(struct bio *bio)
 	struct bio_integrity_payload *bip = bio->bi_integrity;
 	struct bio_set *bs = bio->bi_pool;
 
-	if (bip->bip_owns_buf)
-		kfree(bip->bip_buf);
+	kfree(bip->bip_buf);
 
 	if (bs) {
 		if (bip->bip_slab != BIO_POOL_NONE)
@@ -239,9 +238,11 @@ static int bio_integrity_tag(struct bio *bio, void *tag_buf, unsigned int len,
 {
 	struct bio_integrity_payload *bip = bio->bi_integrity;
 	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
-	unsigned int nr_sectors;
-
-	BUG_ON(bip->bip_buf == NULL);
+	unsigned int nr_sectors, tag_offset, sectors;
+	void *prot_buf;
+	unsigned int prot_offset, prot_len;
+	struct bio_vec *iv;
+	void (*tag_fn)(void *buf, void *tag_buf, unsigned int);
 
 	if (bi->tag_size == 0)
 		return -1;
@@ -255,10 +256,30 @@ static int bio_integrity_tag(struct bio *bio, void *tag_buf, unsigned int len,
 		return -1;
 	}
 
-	if (set)
-		bi->set_tag_fn(bip->bip_buf, tag_buf, nr_sectors);
-	else
-		bi->get_tag_fn(bip->bip_buf, tag_buf, nr_sectors);
+	iv = bip->bip_vec;
+	prot_offset = iv->bv_offset;
+	prot_len = iv->bv_len;
+	prot_buf = kmap_atomic(iv->bv_page);
+	tag_fn = set ? bi->set_tag_fn : bi->get_tag_fn;
+	tag_offset = 0;
+
+	while (nr_sectors) {
+		if (prot_len < bi->tuple_size) {
+			kunmap_atomic(prot_buf);
+			iv++;
+			BUG_ON(iv >= bip->bip_vec + bip->bip_vcnt);
+			prot_offset = iv->bv_offset;
+			prot_len = iv->bv_len;
+			prot_buf = kmap_atomic(iv->bv_page);
+		}
+		sectors = min(prot_len / bi->tuple_size, nr_sectors);
+		tag_fn(prot_buf + prot_offset, tag_buf + tag_offset, sectors);
+		nr_sectors -= sectors;
+		tag_offset += sectors * bi->tuple_size;
+		prot_offset += sectors * bi->tuple_size;
+		prot_len -= sectors * bi->tuple_size;
+	}
+	kunmap_atomic(prot_buf);
 
 	return 0;
 }
@@ -300,28 +321,24 @@ int bio_integrity_get_tag(struct bio *bio, void *tag_buf, unsigned int len)
 }
 EXPORT_SYMBOL(bio_integrity_get_tag);
 
-/**
- * bio_integrity_update_user_buffer - Update user-provided PI buffers for a bio
- * @bio:	bio to generate/verify integrity metadata for
- */
-int bio_integrity_update_user_buffer(struct bio *bio)
+typedef int (walk_buf_fn)(struct blk_integrity_exchg *bi, int flags);
+
+static int bio_integrity_walk_bufs(struct bio *bio, sector_t sector,
+				   walk_buf_fn *mod_fn)
 {
 	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
 	struct blk_integrity_exchg bix;
 	struct bio_vec bv;
 	struct bvec_iter iter;
-	sector_t sector;
 	unsigned int sectors, total, ret;
 	void *prot_buf;
 	unsigned int prot_offset, prot_len, bv_offset, bv_len;
 	struct bio_vec *iv;
 	struct bio_integrity_payload *bip = bio->bi_integrity;
 
-	if (!bi->mod_user_buf_fn)
+	if (!mod_fn)
 		return 0;
 
-	sector = bio->bi_iter.bi_sector;
-
 	total = ret = 0;
 	bix.disk_name = bio->bi_bdev->bd_disk->disk_name;
 	bix.sector_size = bi->sector_size;
@@ -351,7 +368,7 @@ int bio_integrity_update_user_buffer(struct bio *bio)
 			bix.prot_buf = prot_buf + prot_offset;
 			bix.sector = sector;
 
-			ret = bi->mod_user_buf_fn(&bix, bip->bip_user_flags);
+			ret = mod_fn(&bix, bip->bip_user_flags);
 			if (ret) {
 				if (ret == -ENOTTY)
 					ret = 0;
@@ -374,59 +391,19 @@ int bio_integrity_update_user_buffer(struct bio *bio)
 	kunmap_atomic(prot_buf);
 	return ret;
 }
-EXPORT_SYMBOL_GPL(bio_integrity_update_user_buffer);
 
 /**
- * bio_integrity_generate_verify - Generate/verify integrity metadata for a bio
+ * bio_integrity_update_user_buffer - Update user-provided PI buffers for a bio
  * @bio:	bio to generate/verify integrity metadata for
- * @operate:	operate number, 1 for generate, 0 for verify
+ * @sector:	stratin
  */
-static int bio_integrity_generate_verify(struct bio *bio, int operate)
+int bio_integrity_update_user_buffer(struct bio *bio)
 {
 	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
-	struct blk_integrity_exchg bix;
-	struct bio_vec bv;
-	struct bvec_iter iter;
-	sector_t sector;
-	unsigned int sectors, total, ret;
-	void *prot_buf = bio->bi_integrity->bip_buf;
-
-	if (operate)
-		sector = bio->bi_iter.bi_sector;
-	else
-		sector = bio->bi_integrity->bip_iter.bi_sector;
-
-	total = ret = 0;
-	bix.disk_name = bio->bi_bdev->bd_disk->disk_name;
-	bix.sector_size = bi->sector_size;
-
-	bio_for_each_segment(bv, bio, iter) {
-		void *kaddr = kmap_atomic(bv.bv_page);
-		bix.data_buf = kaddr + bv.bv_offset;
-		bix.data_size = bv.bv_len;
-		bix.prot_buf = prot_buf;
-		bix.sector = sector;
-
-		if (operate) {
-			bi->generate_fn(&bix);
-		} else {
-			ret = bi->verify_fn(&bix);
-			if (ret) {
-				kunmap_atomic(kaddr);
-				return ret;
-			}
-		}
-
-		sectors = bv.bv_len / bi->sector_size;
-		sector += sectors;
-		prot_buf += sectors * bi->tuple_size;
-		total += sectors * bi->tuple_size;
-		BUG_ON(total > bio->bi_integrity->bip_iter.bi_size);
-
-		kunmap_atomic(kaddr);
-	}
-	return ret;
+	return bio_integrity_walk_bufs(bio, bio->bi_iter.bi_sector,
+				       bi->mod_user_buf_fn);
 }
+EXPORT_SYMBOL_GPL(bio_integrity_update_user_buffer);
 
 /**
  * bio_integrity_generate - Generate integrity metadata for a bio
@@ -439,7 +416,9 @@ static int bio_integrity_generate_verify(struct bio *bio, int operate)
  */
 static void bio_integrity_generate(struct bio *bio)
 {
-	bio_integrity_generate_verify(bio, 1);
+	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
+	bio_integrity_walk_bufs(bio, bio->bi_iter.bi_sector,
+				(walk_buf_fn *)bi->generate_fn);
 }
 
 static inline unsigned short blk_integrity_tuple_size(struct blk_integrity *bi)
@@ -479,7 +458,6 @@ int bio_integrity_prep_buffer(struct bio *bio, int rw,
 
 	sectors = bio_integrity_hw_sectors(bi, bio_sectors(bio));
 
-	/* Allocate kernel buffer for protection data */
 	len = sectors * blk_integrity_tuple_size(bi);
 	end = (pi->pi_offset + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
 	start = pi->pi_offset >> PAGE_SHIFT;
@@ -497,8 +475,6 @@ int bio_integrity_prep_buffer(struct bio *bio, int rw,
 		return -EIO;
 	}
 
-	bip->bip_owns_buf = 0;
-	bip->bip_buf = NULL;
 	bip->bip_iter.bi_size = len;
 	bip->bip_iter.bi_sector = bio->bi_iter.bi_sector;
 	bip->bip_user_flags = pi->pi_userflags;
@@ -591,7 +567,6 @@ int bio_integrity_prep(struct bio *bio)
 		return -EIO;
 	}
 
-	bip->bip_owns_buf = 1;
 	bip->bip_buf = buf;
 	bip->bip_iter.bi_size = len;
 	bip->bip_iter.bi_sector = bio->bi_iter.bi_sector;
@@ -646,7 +621,10 @@ EXPORT_SYMBOL(bio_integrity_prep);
  */
 static int bio_integrity_verify(struct bio *bio)
 {
-	return bio_integrity_generate_verify(bio, 0);
+	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
+	return bio_integrity_walk_bufs(bio,
+				       bio->bi_integrity->bip_iter.bi_sector,
+				       (walk_buf_fn *)bi->verify_fn);
 }
 
 /**
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 5bd9618..c2ad1a8 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -292,14 +292,12 @@ struct bio_integrity_payload {
 
 	struct bvec_iter	bip_iter;
 
-	/* kill - should just use bip_vec */
 	void			*bip_buf;	/* generated integrity data */
 
 	bio_end_io_t		*bip_end_io;	/* saved I/O completion fn */
 
 	unsigned short		bip_slab;	/* slab the bip came from */
 	unsigned short		bip_vcnt;	/* # of integrity bio_vecs */
-	unsigned		bip_owns_buf:1;	/* should free bip_buf */
 
 	struct work_struct	bip_work;	/* I/O completion */
 

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