[PATCH 25/27] block: Add bio_alloc_pages()

From: Kent Overstreet
Date: Tue Feb 19 2013 - 19:24:13 EST


More utility code to replace stuff that's getting open coded.

Signed-off-by: Kent Overstreet <koverstreet@xxxxxxxxxx>
CC: Jens Axboe <axboe@xxxxxxxxx>
CC: NeilBrown <neilb@xxxxxxx>
---
drivers/md/raid1.c | 16 +++-------------
fs/bio.c | 28 ++++++++++++++++++++++++++++
include/linux/bio.h | 1 +
3 files changed, 32 insertions(+), 13 deletions(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 981fd4f..95afd45 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -92,7 +92,6 @@ static void r1bio_pool_free(void *r1_bio, void *data)
static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
{
struct pool_info *pi = data;
- struct page *page;
struct r1bio *r1_bio;
struct bio *bio;
int i, j;
@@ -122,14 +121,10 @@ static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
j = 1;
while(j--) {
bio = r1_bio->bios[j];
- for (i = 0; i < RESYNC_PAGES; i++) {
- page = alloc_page(gfp_flags);
- if (unlikely(!page))
- goto out_free_pages;
+ bio->bi_vcnt = RESYNC_PAGES;

- bio->bi_io_vec[i].bv_page = page;
- bio->bi_vcnt = i+1;
- }
+ if (bio_alloc_pages(bio, gfp_flags))
+ goto out_free_bio;
}
/* If not user-requests, copy the page pointers to all bios */
if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
@@ -143,11 +138,6 @@ static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)

return r1_bio;

-out_free_pages:
- for (j=0 ; j < pi->raid_disks; j++)
- for (i=0; i < r1_bio->bios[j]->bi_vcnt ; i++)
- put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page);
- j = -1;
out_free_bio:
while (++j < pi->raid_disks)
bio_put(r1_bio->bios[j]);
diff --git a/fs/bio.c b/fs/bio.c
index fe3aee90..e545a44 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -830,6 +830,34 @@ void bio_advance(struct bio *bio, unsigned bytes)
EXPORT_SYMBOL(bio_advance);

/**
+ * bio_alloc_pages - allocates a single page for each bvec in a bio
+ * @bio: bio to allocate pages for
+ * @gfp_mask: flags for allocation
+ *
+ * Allocates pages up to @bio->bi_vcnt.
+ *
+ * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are
+ * freed.
+ */
+int bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
+{
+ int i;
+ struct bio_vec *bv;
+
+ bio_for_each_segment_all(bv, bio, i) {
+ bv->bv_page = alloc_page(gfp_mask);
+ if (!bv->bv_page) {
+ while (--bv >= bio->bi_io_vec)
+ __free_page(bv->bv_page);
+ return -ENOMEM;
+ }
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(bio_alloc_pages);
+
+/**
* bio_copy_data - copy contents of data buffers from one chain of bios to
* another
* @src: source bio list
diff --git a/include/linux/bio.h b/include/linux/bio.h
index be2efa0..e25378f 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -298,6 +298,7 @@ static inline void bio_flush_dcache_pages(struct bio *bi)
#endif

extern void bio_copy_data(struct bio *dst, struct bio *src);
+extern int bio_alloc_pages(struct bio *bio, gfp_t gfp);

extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
unsigned long, unsigned int, int, gfp_t);
--
1.7.12

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