[PATCH 4/5] block: turn bio_kmalloc into a simple kmalloc wrapper

From: Christoph Hellwig
Date: Tue Mar 01 2022 - 03:46:37 EST

Remove the magic autofree semantics and require the callers to explicitly
call bio_init to initialize the bio.

This allows bio_free to catch accidental bio_put calls on bio_init()ed
bios as well.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
block/bio.c | 47 ++++++++++++------------------
block/blk-crypto-fallback.c | 14 +++++----
block/blk-map.c | 42 ++++++++++++++++----------
drivers/block/pktcdvd.c | 25 ++++++++--------
drivers/md/bcache/debug.c | 10 ++++---
drivers/md/dm-bufio.c | 9 +++---
drivers/md/raid1.c | 12 +++++---
drivers/md/raid10.c | 21 ++++++++-----
drivers/target/target_core_pscsi.c | 10 +++----
fs/squashfs/block.c | 9 +++---
include/linux/bio.h | 2 +-
11 files changed, 108 insertions(+), 93 deletions(-)

diff --git a/block/bio.c b/block/bio.c
index b15f5466ce084..e8ff5dd6d145f 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -224,24 +224,13 @@ EXPORT_SYMBOL(bio_uninit);
static void bio_free(struct bio *bio)
{
struct bio_set *bs = bio->bi_pool;
- void *p;
-
- bio_uninit(bio);
+ void *p = bio;

- if (bs) {
- bvec_free(&bs->bvec_pool, bio->bi_io_vec, bio->bi_max_vecs);
+ WARN_ON_ONCE(!bs);

- /*
- * If we have front padding, adjust the bio pointer before freeing
- */
- p = bio;
- p -= bs->front_pad;
-
- mempool_free(p, &bs->bio_pool);
- } else {
- /* Bio was allocated by bio_kmalloc() */
- kfree(bio);
- }
+ bio_uninit(bio);
+ bvec_free(&bs->bvec_pool, bio->bi_io_vec, bio->bi_max_vecs);
+ mempool_free(p - bs->front_pad, &bs->bio_pool);
}

/*
@@ -529,28 +518,28 @@ struct bio *bio_alloc_bioset(struct block_device *bdev, unsigned short nr_vecs,
EXPORT_SYMBOL(bio_alloc_bioset);

/**
- * bio_kmalloc - kmalloc a bio for I/O
+ * bio_kmalloc - kmalloc a bio
+ * @nr_vecs: number of bio_vecs to allocate
* @gfp_mask: the GFP_* mask given to the slab allocator
- * @nr_iovecs: number of iovecs to pre-allocate
*
- * Use kmalloc to allocate and initialize a bio.
+ * Use kmalloc to allocate a bio (including bvecs). The bio must be initialized
+ * using bio_init() before use. To free a bio returned from this function use
+ * kfree() after calling bio_uninit(). A bio returned from this function can
+ * be reused by calling bio_uninit() before calling bio_init() again.
+ *
+ * Note that unlike bio_alloc() or bio_alloc_bioset() allocations from this
+ * function are not backed by a mempool can can fail. Do not use this function
+ * for allocations in the file system I/O path.
*
* Returns: Pointer to new bio on success, NULL on failure.
*/
-struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned short nr_iovecs)
+struct bio *bio_kmalloc(unsigned short nr_vecs, gfp_t gfp_mask)
{
struct bio *bio;

- if (nr_iovecs > UIO_MAXIOV)
+ if (nr_vecs > UIO_MAXIOV)
return NULL;
-
- bio = kmalloc(struct_size(bio, bi_inline_vecs, nr_iovecs), gfp_mask);
- if (unlikely(!bio))
- return NULL;
- bio_init(bio, NULL, nr_iovecs ? bio->bi_inline_vecs : NULL, nr_iovecs,
- 0);
- bio->bi_pool = NULL;
- return bio;
+ return kmalloc(struct_size(bio, bi_inline_vecs, nr_vecs), gfp_mask);
}
EXPORT_SYMBOL(bio_kmalloc);

diff --git a/block/blk-crypto-fallback.c b/block/blk-crypto-fallback.c
index 18c8eafe20b94..1a624b75da94f 100644
--- a/block/blk-crypto-fallback.c
+++ b/block/blk-crypto-fallback.c
@@ -152,23 +152,25 @@ static void blk_crypto_fallback_encrypt_endio(struct bio *enc_bio)

src_bio->bi_status = enc_bio->bi_status;

- bio_put(enc_bio);
+ bio_uninit(enc_bio);
+ kfree(enc_bio);
bio_endio(src_bio);
}

static struct bio *blk_crypto_fallback_clone_bio(struct bio *bio_src)
{
+ unsigned int nr_segs = bio_segments(bio_src);
struct bvec_iter iter;
struct bio_vec bv;
struct bio *bio;

- bio = bio_kmalloc(GFP_NOIO, bio_segments(bio_src));
+ bio = bio_kmalloc(nr_segs, GFP_NOIO);
if (!bio)
return NULL;
- bio->bi_bdev = bio_src->bi_bdev;
+ bio_init(bio, bio_src->bi_bdev, bio->bi_inline_vecs, nr_segs,
+ bio_src->bi_opf);
if (bio_flagged(bio_src, BIO_REMAPPED))
bio_set_flag(bio, BIO_REMAPPED);
- bio->bi_opf = bio_src->bi_opf;
bio->bi_ioprio = bio_src->bi_ioprio;
bio->bi_write_hint = bio_src->bi_write_hint;
bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector;
@@ -364,8 +366,8 @@ static bool blk_crypto_fallback_encrypt_bio(struct bio **bio_ptr)
blk_crypto_put_keyslot(slot);
out_put_enc_bio:
if (enc_bio)
- bio_put(enc_bio);
-
+ bio_uninit(enc_bio);
+ kfree(enc_bio);
return ret;
}

diff --git a/block/blk-map.c b/block/blk-map.c
index 4526adde01564..59be60e69e7af 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -152,10 +152,10 @@ static int bio_copy_user_iov(struct request *rq, struct rq_map_data *map_data,
nr_pages = bio_max_segs(DIV_ROUND_UP(offset + len, PAGE_SIZE));

ret = -ENOMEM;
- bio = bio_kmalloc(gfp_mask, nr_pages);
+ bio = bio_kmalloc(nr_pages, gfp_mask);
if (!bio)
goto out_bmd;
- bio->bi_opf |= req_op(rq);
+ bio_init(bio, NULL, bio->bi_inline_vecs, nr_pages, req_op(rq));

if (map_data) {
nr_pages = 1 << map_data->page_order;
@@ -224,7 +224,8 @@ static int bio_copy_user_iov(struct request *rq, struct rq_map_data *map_data,
cleanup:
if (!map_data)
bio_free_pages(bio);
- bio_put(bio);
+ bio_uninit(bio);
+ kfree(bio);
out_bmd:
kfree(bmd);
return ret;
@@ -234,6 +235,7 @@ static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
gfp_t gfp_mask)
{
unsigned int max_sectors = queue_max_hw_sectors(rq->q);
+ unsigned int nr_vecs = iov_iter_npages(iter, BIO_MAX_VECS);
struct bio *bio;
int ret;
int j;
@@ -241,10 +243,10 @@ static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
if (!iov_iter_count(iter))
return -EINVAL;

- bio = bio_kmalloc(gfp_mask, iov_iter_npages(iter, BIO_MAX_VECS));
+ bio = bio_kmalloc(nr_vecs, gfp_mask);
if (!bio)
return -ENOMEM;
- bio->bi_opf |= req_op(rq);
+ bio_init(bio, NULL, bio->bi_inline_vecs, nr_vecs, req_op(rq));

while (iov_iter_count(iter)) {
struct page **pages;
@@ -303,7 +305,8 @@ static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,

out_unmap:
bio_release_pages(bio, false);
- bio_put(bio);
+ bio_uninit(bio);
+ kfree(bio);
return ret;
}

@@ -323,7 +326,8 @@ static void bio_invalidate_vmalloc_pages(struct bio *bio)
static void bio_map_kern_endio(struct bio *bio)
{
bio_invalidate_vmalloc_pages(bio);
- bio_put(bio);
+ bio_uninit(bio);
+ kfree(bio);
}

/**
@@ -348,9 +352,10 @@ static struct bio *bio_map_kern(struct request_queue *q, void *data,
int offset, i;
struct bio *bio;

- bio = bio_kmalloc(gfp_mask, nr_pages);
+ bio = bio_kmalloc(nr_pages, gfp_mask);
if (!bio)
return ERR_PTR(-ENOMEM);
+ bio_init(bio, NULL, bio->bi_inline_vecs, nr_pages, 0);

if (is_vmalloc) {
flush_kernel_vmap_range(data, len);
@@ -374,7 +379,8 @@ static struct bio *bio_map_kern(struct request_queue *q, void *data,
if (bio_add_pc_page(q, bio, page, bytes,
offset) < bytes) {
/* we don't support partial mappings */
- bio_put(bio);
+ bio_uninit(bio);
+ kfree(bio);
return ERR_PTR(-EINVAL);
}

@@ -390,7 +396,8 @@ static struct bio *bio_map_kern(struct request_queue *q, void *data,
static void bio_copy_kern_endio(struct bio *bio)
{
bio_free_pages(bio);
- bio_put(bio);
+ bio_uninit(bio);
+ kfree(bio);
}

static void bio_copy_kern_endio_read(struct bio *bio)
@@ -435,9 +442,10 @@ static struct bio *bio_copy_kern(struct request_queue *q, void *data,
return ERR_PTR(-EINVAL);

nr_pages = end - start;
- bio = bio_kmalloc(gfp_mask, nr_pages);
+ bio = bio_kmalloc(nr_pages, gfp_mask);
if (!bio)
return ERR_PTR(-ENOMEM);
+ bio_init(bio, NULL, bio->bi_inline_vecs, nr_pages, 0);

while (len) {
struct page *page;
@@ -471,7 +479,8 @@ static struct bio *bio_copy_kern(struct request_queue *q, void *data,

cleanup:
bio_free_pages(bio);
- bio_put(bio);
+ bio_uninit(bio);
+ kfree(bio);
return ERR_PTR(-ENOMEM);
}

@@ -602,7 +611,8 @@ int blk_rq_unmap_user(struct bio *bio)

next_bio = bio;
bio = bio->bi_next;
- bio_put(next_bio);
+ bio_uninit(next_bio);
+ kfree(next_bio);
}

return ret;
@@ -648,8 +658,10 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
bio->bi_opf |= req_op(rq);

ret = blk_rq_append_bio(rq, bio);
- if (unlikely(ret))
- bio_put(bio);
+ if (unlikely(ret)) {
+ bio_uninit(bio);
+ kfree(bio);
+ }
return ret;
}
EXPORT_SYMBOL(blk_rq_map_kern);
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index be749c686feb7..6aec11ed185d8 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -522,9 +522,10 @@ static struct packet_data *pkt_alloc_packet_data(int frames)
goto no_pkt;

pkt->frames = frames;
- pkt->w_bio = bio_kmalloc(GFP_KERNEL, frames);
+ pkt->w_bio = bio_kmalloc(frames, GFP_KERNEL);
if (!pkt->w_bio)
goto no_bio;
+ bio_init(pkt->w_bio, NULL, pkt->w_bio->bi_inline_vecs, frames, 0);

for (i = 0; i < frames / FRAMES_PER_PAGE; i++) {
pkt->pages[i] = alloc_page(GFP_KERNEL|__GFP_ZERO);
@@ -536,10 +537,10 @@ static struct packet_data *pkt_alloc_packet_data(int frames)
bio_list_init(&pkt->orig_bios);

for (i = 0; i < frames; i++) {
- struct bio *bio = bio_kmalloc(GFP_KERNEL, 1);
+ struct bio *bio = bio_kmalloc(1, GFP_KERNEL);
if (!bio)
goto no_rd_bio;
-
+ bio_init(bio, NULL, bio->bi_inline_vecs, 1, 0);
pkt->r_bios[i] = bio;
}

@@ -547,16 +548,16 @@ static struct packet_data *pkt_alloc_packet_data(int frames)

no_rd_bio:
for (i = 0; i < frames; i++) {
- struct bio *bio = pkt->r_bios[i];
- if (bio)
- bio_put(bio);
+ if (pkt->r_bios[i])
+ bio_uninit(pkt->r_bios[i]);
+ kfree(pkt->r_bios[i]);
}
-
no_page:
for (i = 0; i < frames / FRAMES_PER_PAGE; i++)
if (pkt->pages[i])
__free_page(pkt->pages[i]);
- bio_put(pkt->w_bio);
+ bio_uninit(pkt->w_bio);
+ kfree(pkt->w_bio);
no_bio:
kfree(pkt);
no_pkt:
@@ -571,13 +572,13 @@ static void pkt_free_packet_data(struct packet_data *pkt)
int i;

for (i = 0; i < pkt->frames; i++) {
- struct bio *bio = pkt->r_bios[i];
- if (bio)
- bio_put(bio);
+ bio_uninit(pkt->r_bios[i]);
+ kfree(pkt->r_bios[i]);
}
for (i = 0; i < pkt->frames / FRAMES_PER_PAGE; i++)
__free_page(pkt->pages[i]);
- bio_put(pkt->w_bio);
+ bio_uninit(pkt->w_bio);
+ kfree(pkt->w_bio);
kfree(pkt);
}

diff --git a/drivers/md/bcache/debug.c b/drivers/md/bcache/debug.c
index 6230dfdd9286e..7510d1c983a5e 100644
--- a/drivers/md/bcache/debug.c
+++ b/drivers/md/bcache/debug.c
@@ -107,15 +107,16 @@ void bch_btree_verify(struct btree *b)

void bch_data_verify(struct cached_dev *dc, struct bio *bio)
{
+ unsigned int nr_segs = bio_segments(bio);
struct bio *check;
struct bio_vec bv, cbv;
struct bvec_iter iter, citer = { 0 };

- check = bio_kmalloc(GFP_NOIO, bio_segments(bio));
+ check = bio_kmalloc(nr_segs, GFP_NOIO);
if (!check)
return;
- bio_set_dev(check, bio->bi_bdev);
- check->bi_opf = REQ_OP_READ;
+ bio_init(check, bio->bi_bdev, check->bi_inline_vecs, nr_segs,
+ REQ_OP_READ);
check->bi_iter.bi_sector = bio->bi_iter.bi_sector;
check->bi_iter.bi_size = bio->bi_iter.bi_size;

@@ -146,7 +147,8 @@ void bch_data_verify(struct cached_dev *dc, struct bio *bio)

bio_free_pages(check);
out_put:
- bio_put(check);
+ bio_uninit(check);
+ kfree(check);
}

#endif
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index e9cbc70d5a0ee..5ffa1dcf84cfc 100644
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -611,7 +611,8 @@ static void bio_complete(struct bio *bio)
{
struct dm_buffer *b = bio->bi_private;
blk_status_t status = bio->bi_status;
- bio_put(bio);
+ bio_uninit(bio);
+ kfree(bio);
b->end_io(b, status);
}

@@ -626,16 +627,14 @@ static void use_bio(struct dm_buffer *b, int rw, sector_t sector,
if (unlikely(b->c->sectors_per_block_bits < PAGE_SHIFT - SECTOR_SHIFT))
vec_size += 2;

- bio = bio_kmalloc(GFP_NOWAIT | __GFP_NORETRY | __GFP_NOWARN, vec_size);
+ bio = bio_kmalloc(vec_size, GFP_NOWAIT | __GFP_NORETRY | __GFP_NOWARN);
if (!bio) {
dmio:
use_dmio(b, rw, sector, n_sectors, offset);
return;
}
-
+ bio_init(bio, b->c->bdev, bio->bi_inline_vecs, vec_size, rw);
bio->bi_iter.bi_sector = sector;
- bio_set_dev(bio, b->c->bdev);
- bio_set_op_attrs(bio, rw, 0);
bio->bi_end_io = bio_complete;
bio->bi_private = b;

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index c3288d46948de..12627d1c99c36 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -165,9 +165,10 @@ static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
* Allocate bios : 1 for reading, n-1 for writing
*/
for (j = pi->raid_disks ; j-- ; ) {
- bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
+ bio = bio_kmalloc(RESYNC_PAGES, gfp_flags);
if (!bio)
goto out_free_bio;
+ bio_init(bio, NULL, bio->bi_inline_vecs, RESYNC_PAGES, 0);
r1_bio->bios[j] = bio;
}
/*
@@ -206,8 +207,10 @@ static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
resync_free_pages(&rps[j]);

out_free_bio:
- while (++j < pi->raid_disks)
- bio_put(r1_bio->bios[j]);
+ while (++j < pi->raid_disks) {
+ bio_uninit(r1_bio->bios[j]);
+ kfree(r1_bio->bios[j]);
+ }
kfree(rps);

out_free_r1bio:
@@ -225,7 +228,8 @@ static void r1buf_pool_free(void *__r1_bio, void *data)
for (i = pi->raid_disks; i--; ) {
rp = get_resync_pages(r1bio->bios[i]);
resync_free_pages(rp);
- bio_put(r1bio->bios[i]);
+ bio_uninit(r1bio->bios[i]);
+ kfree(r1bio->bios[i]);
}

/* resync pages array stored in the 1st bio's .bi_private */
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 5dd2e17e1d0ea..781b7b8a4b558 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -145,15 +145,17 @@ static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
* Allocate bios.
*/
for (j = nalloc ; j-- ; ) {
- bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
+ bio = bio_kmalloc(RESYNC_PAGES, gfp_flags);
if (!bio)
goto out_free_bio;
+ bio_init(bio, NULL, bio->bi_inline_vecs, RESYNC_PAGES, 0);
r10_bio->devs[j].bio = bio;
if (!conf->have_replacement)
continue;
- bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
+ bio = bio_kmalloc(RESYNC_PAGES, gfp_flags);
if (!bio)
goto out_free_bio;
+ bio_init(bio, NULL, bio->bi_inline_vecs, RESYNC_PAGES, 0);
r10_bio->devs[j].repl_bio = bio;
}
/*
@@ -197,9 +199,11 @@ static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
out_free_bio:
for ( ; j < nalloc; j++) {
if (r10_bio->devs[j].bio)
- bio_put(r10_bio->devs[j].bio);
+ bio_uninit(r10_bio->devs[j].bio);
+ kfree(r10_bio->devs[j].bio);
if (r10_bio->devs[j].repl_bio)
- bio_put(r10_bio->devs[j].repl_bio);
+ bio_uninit(r10_bio->devs[j].repl_bio);
+ kfree(r10_bio->devs[j].repl_bio);
}
kfree(rps);
out_free_r10bio:
@@ -220,12 +224,15 @@ static void r10buf_pool_free(void *__r10_bio, void *data)
if (bio) {
rp = get_resync_pages(bio);
resync_free_pages(rp);
- bio_put(bio);
+ bio_uninit(bio);
+ kfree(bio);
}

bio = r10bio->devs[j].repl_bio;
- if (bio)
- bio_put(bio);
+ if (bio) {
+ bio_uninit(bio);
+ kfree(bio);
+ }
}

/* resync pages array stored in the 1st bio's .bi_private */
diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c
index bd8ae07273f14..edda1a89d9357 100644
--- a/drivers/target/target_core_pscsi.c
+++ b/drivers/target/target_core_pscsi.c
@@ -820,7 +820,8 @@ static ssize_t pscsi_show_configfs_dev_params(struct se_device *dev, char *b)

static void pscsi_bi_endio(struct bio *bio)
{
- bio_put(bio);
+ bio_uninit(bio);
+ kfree(bio);
}

static sense_reason_t
@@ -863,14 +864,13 @@ pscsi_map_sg(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
if (!bio) {
new_bio:
nr_vecs = bio_max_segs(nr_pages);
- bio = bio_kmalloc(GFP_KERNEL, nr_vecs);
+ bio = bio_kmalloc(nr_vecs, GFP_KERNEL);
if (!bio)
goto fail;
+ bio_init(bio, NULL, bio->bi_inline_vecs, nr_vecs,
+ rw ? REQ_OP_WRITE : REQ_OP_READ);
bio->bi_end_io = pscsi_bi_endio;

- if (rw)
- bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
-
pr_debug("PSCSI: Allocated bio: %p,"
" dir: %s nr_vecs: %d\n", bio,
(rw) ? "rw" : "r", nr_vecs);
diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c
index 4311a32218928..930eb530fa622 100644
--- a/fs/squashfs/block.c
+++ b/fs/squashfs/block.c
@@ -86,12 +86,10 @@ static int squashfs_bio_read(struct super_block *sb, u64 index, int length,
int error, i;
struct bio *bio;

- bio = bio_kmalloc(GFP_NOIO, page_count);
+ bio = bio_kmalloc(page_count, GFP_NOIO);
if (!bio)
return -ENOMEM;
- bio_set_dev(bio, sb->s_bdev);
- bio->bi_opf = REQ_OP_READ;
-
+ bio_init(bio, sb->s_bdev, bio->bi_inline_vecs, page_count, REQ_OP_READ);
bio->bi_iter.bi_sector = block * (msblk->devblksize >> SECTOR_SHIFT);

for (i = 0; i < page_count; ++i) {
@@ -121,7 +119,8 @@ static int squashfs_bio_read(struct super_block *sb, u64 index, int length,

out_free_bio:
bio_free_pages(bio);
- bio_put(bio);
+ bio_uninit(bio);
+ kfree(bio);
return error;
}

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 7523aba4ddf7c..9c01b6f516120 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -410,7 +410,7 @@ struct bio *bio_alloc_bioset(struct block_device *bdev, unsigned short nr_vecs,
struct bio_set *bs);
struct bio *bio_alloc_kiocb(struct kiocb *kiocb, struct block_device *bdev,
unsigned short nr_vecs, unsigned int opf, struct bio_set *bs);
-struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned short nr_iovecs);
+struct bio *bio_kmalloc(unsigned short nr_vecs, gfp_t gfp_mask);
extern void bio_put(struct bio *);

struct bio *bio_alloc_clone(struct block_device *bdev, struct bio *bio_src,
--
2.30.2