Currently bio_integrity_copy_user() uses bip_vec array to store two
different things: (a) kernel allocated bounce buffer (b) bunch of extra
bvecs to pinned user memory.
This leads to unwieldy handling at places.
The patch cleans this up and uses bip_vec for just kernel allocated meta
buffer. The bio_vecs (to pinned user memory) and their count are now
stored seprately into bip. Existing memory (of the field bip_work) is
reused so that bip does not grow unconditionally.
Based on an earlier patch from Keith Busch.
Signed-off-by: Kanchan Joshi <joshi.k@xxxxxxxxxxx>
---
block/bio-integrity.c | 28 ++++++++++++++++++----------
include/linux/bio.h | 12 +++++++++++-
2 files changed, 29 insertions(+), 11 deletions(-)
diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index 2e3e8e04961e..47634b89d27c 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -105,8 +105,8 @@ static void bio_integrity_unpin_bvec(struct bio_vec *bv, int nr_vecs,
static void bio_integrity_uncopy_user(struct bio_integrity_payload *bip)
{
- unsigned short nr_vecs = bip->bip_max_vcnt - 1;
- struct bio_vec *copy = &bip->bip_vec[1];
+ unsigned short nr_vecs = bip->copy_vcnt;
+ struct bio_vec *copy = bip->copy_vec;
size_t bytes = bip->bip_iter.bi_size;
struct iov_iter iter;
int ret;
@@ -116,6 +116,7 @@ static void bio_integrity_uncopy_user(struct bio_integrity_payload *bip)
WARN_ON_ONCE(ret != bytes);
bio_integrity_unpin_bvec(copy, nr_vecs, true);
+ kfree(copy);
}
static void bio_integrity_unmap_user(struct bio_integrity_payload *bip)
@@ -208,6 +209,7 @@ static int bio_integrity_copy_user(struct bio *bio, struct bio_vec *bvec,
unsigned int direction, u32 seed)
{
bool write = direction == ITER_SOURCE;
+ struct bio_vec *copy_vec = NULL;
struct bio_integrity_payload *bip;
struct iov_iter iter;
void *buf;
@@ -224,7 +226,7 @@ static int bio_integrity_copy_user(struct bio *bio, struct bio_vec *bvec,
goto free_buf;
}
- bip = bio_integrity_alloc(bio, GFP_KERNEL, 1);
+ bio_integrity_unpin_bvec(bvec, nr_vecs, false);
} else {
memset(buf, 0, len);
@@ -232,19 +234,21 @@ static int bio_integrity_copy_user(struct bio *bio, struct bio_vec *bvec,
* We need to preserve the original bvec and the number of vecs
* in it for completion handling
*/
- bip = bio_integrity_alloc(bio, GFP_KERNEL, nr_vecs + 1);
+ copy_vec = kcalloc(nr_vecs, sizeof(*bvec), GFP_KERNEL);
+ if (!copy_vec) {
+ ret = -ENOMEM;
+ goto free_buf;
+ }
+ memcpy(copy_vec, bvec, nr_vecs * sizeof(*bvec));
+
}
+ bip = bio_integrity_alloc(bio, GFP_KERNEL, 1);
if (IS_ERR(bip)) {
ret = PTR_ERR(bip);
- goto free_buf;
+ goto free_copy;
}
- if (write)
- bio_integrity_unpin_bvec(bvec, nr_vecs, false);
- else
- memcpy(&bip->bip_vec[1], bvec, nr_vecs * sizeof(*bvec));
-
ret = bio_integrity_add_page(bio, virt_to_page(buf), len,
offset_in_page(buf));
if (ret != len) {
@@ -254,9 +258,13 @@ static int bio_integrity_copy_user(struct bio *bio, struct bio_vec *bvec,
bip->bip_flags |= BIP_INTEGRITY_USER | BIP_COPY_USER;
bip->bip_iter.bi_sector = seed;
+ bip->copy_vec = copy_vec;
+ bip->copy_vcnt = nr_vecs;
return 0;
free_bip:
bio_integrity_free(bio);
+free_copy:
+ kfree(copy_vec);
free_buf:
kfree(buf);
return ret;
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 9b8a369f44bc..ffbfa43d51af 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -345,7 +345,17 @@ struct bio_integrity_payload {
struct bvec_iter bio_iter; /* for rewinding parent bio */
- struct work_struct bip_work; /* I/O completion */
+ union {
+ /*
+ * bip_work is used only for block-layer sent integrity.
+ * For user sent integrity, reuse the same memory.
+ */
+ struct work_struct bip_work; /* I/O completion */
+ struct {
+ struct bio_vec *copy_vec; /* pinned user memory */
+ unsigned short copy_vcnt; /* # of bio_vecs for above */
+ };
+ };
struct bio_vec *bip_vec;
struct bio_vec bip_inline_vecs[];/* embedded bvec array */
--
2.25.1
