block: Add bio_alloc_pages()

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

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: NeilBrown <neilb@suse.de>

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index a7ea954..aeb4e3f 100644 (file)
--- 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 fe3aee9..e545a44 100644 (file)
--- 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 (file)
--- 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);