3.2.51-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Kent Overstreet <koverstreet@xxxxxxxxxx>
commit d74c6d514fe314b8bdab58b487b25992291577ec upstream.
__bio_for_each_segment() iterates bvecs from the specified index
instead of bio->bv_idx. Currently, the only usage is to walk all the
bvecs after the bio has been advanced by specifying 0 index.
For immutable bvecs, we need to split these apart;
bio_for_each_segment() is going to have a different implementation.
This will also help document the intent of code that's using it -
bio_for_each_segment_all() is only legal to use for code that owns the
bio.
Signed-off-by: Kent Overstreet <koverstreet@xxxxxxxxxx>
CC: Jens Axboe <axboe@xxxxxxxxx>
CC: Neil Brown <neilb@xxxxxxx>
CC: Boaz Harrosh <bharrosh@xxxxxxxxxxx>
[bwh: Backported to 3.2: drop inapplicable change to drivers/block/rbd.c.
This is a prerequisite for commit 35dc248383bb 'sg: Fix user memory
corruption when SG_IO is interrupted by a signal']
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1139,7 +1139,7 @@ read_again:
* know the original bi_idx, so we just free
* them all
*/
- __bio_for_each_segment(bvec, mbio, j, 0)
+ bio_for_each_segment_all(bvec, mbio, j)
bvec->bv_page = r1_bio->behind_bvecs[j].bv_page;
if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
atomic_inc(&r1_bio->behind_remaining);
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -734,7 +734,7 @@ static int __bio_copy_iov(struct bio *bi
int iov_idx = 0;
unsigned int iov_off = 0;
- __bio_for_each_segment(bvec, bio, i, 0) {
+ bio_for_each_segment_all(bvec, bio, i) {
char *bv_addr = page_address(bvec->bv_page);
unsigned int bv_len = iovecs[i].bv_len;
@@ -916,7 +916,7 @@ struct bio *bio_copy_user_iov(struct req
return bio;
cleanup:
if (!map_data)
- bio_for_each_segment(bvec, bio, i)
+ bio_for_each_segment_all(bvec, bio, i)
__free_page(bvec->bv_page);
bio_put(bio);
@@ -1130,7 +1130,7 @@ static void __bio_unmap_user(struct bio
/*
* make sure we dirty pages we wrote to
*/
- __bio_for_each_segment(bvec, bio, i, 0) {
+ bio_for_each_segment_all(bvec, bio, i) {
if (bio_data_dir(bio) == READ)
set_page_dirty_lock(bvec->bv_page);
@@ -1236,7 +1236,7 @@ static void bio_copy_kern_endio(struct b
int i;
char *p = bmd->sgvecs[0].iov_base;
- __bio_for_each_segment(bvec, bio, i, 0) {
+ bio_for_each_segment_all(bvec, bio, i) {
char *addr = page_address(bvec->bv_page);
int len = bmd->iovecs[i].bv_len;
@@ -1276,7 +1276,7 @@ struct bio *bio_copy_kern(struct request
if (!reading) {
void *p = data;
- bio_for_each_segment(bvec, bio, i) {
+ bio_for_each_segment_all(bvec, bio, i) {
char *addr = page_address(bvec->bv_page);
memcpy(addr, p, bvec->bv_len);
@@ -1556,7 +1556,7 @@ sector_t bio_sector_offset(struct bio *b
if (index >= bio->bi_idx)
index = bio->bi_vcnt - 1;
- __bio_for_each_segment(bv, bio, i, 0) {
+ bio_for_each_segment_all(bv, bio, i) {
if (i == index) {
if (offset > bv->bv_offset)
sectors += (offset - bv->bv_offset) / sector_sz;
--- a/fs/exofs/ore.c
+++ b/fs/exofs/ore.c
@@ -401,7 +401,7 @@ static void _clear_bio(struct bio *bio)
struct bio_vec *bv;
unsigned i;
- __bio_for_each_segment(bv, bio, i, 0) {
+ bio_for_each_segment_all(bv, bio, i) {
unsigned this_count = bv->bv_len;
if (likely(PAGE_SIZE == this_count))
--- a/fs/exofs/ore_raid.c
+++ b/fs/exofs/ore_raid.c
@@ -432,7 +432,7 @@ static void _mark_read4write_pages_uptod
if (!bio)
continue;
- __bio_for_each_segment(bv, bio, i, 0) {
+ bio_for_each_segment_all(bv, bio, i) {
struct page *page = bv->bv_page;
SetPageUptodate(page);
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -135,16 +135,27 @@ static inline int bio_has_allocated_vec(
#define bio_io_error(bio) bio_endio((bio), -EIO)
/*
- * drivers should not use the __ version unless they _really_ want to
- * run through the entire bio and not just pending pieces
+ * drivers should not use the __ version unless they _really_ know what
+ * they're doing
*/
#define __bio_for_each_segment(bvl, bio, i, start_idx) \
for (bvl = bio_iovec_idx((bio), (start_idx)), i = (start_idx); \
i < (bio)->bi_vcnt; \
bvl++, i++)
+/*
+ * drivers should _never_ use the all version - the bio may have been split
+ * before it got to the driver and the driver won't own all of it
+ */
+#define bio_for_each_segment_all(bvl, bio, i) \
+ for (i = 0; \
+ bvl = bio_iovec_idx((bio), (i)), i < (bio)->bi_vcnt; \
+ i++)
+
#define bio_for_each_segment(bvl, bio, i) \
- __bio_for_each_segment(bvl, bio, i, (bio)->bi_idx)
+ for (i = (bio)->bi_idx; \
+ bvl = bio_iovec_idx((bio), (i)), i < (bio)->bi_vcnt; \
+ i++)
/*
* get a reference to a bio, so it won't disappear. the intended use is
--- a/mm/bounce.c
+++ b/mm/bounce.c
@@ -132,7 +132,7 @@ static void bounce_end_io(struct bio *bi
/*
* free up bounce indirect pages used
*/
- __bio_for_each_segment(bvec, bio, i, 0) {
+ bio_for_each_segment_all(bvec, bio, i) {
org_vec = bio_orig->bi_io_vec + i;
if (bvec->bv_page == org_vec->bv_page)
continue;
--
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