Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma

[linux-2.6-block.git] / block / bio.c

diff --git a/block/bio.c b/block/bio.c
index 2a00d349cd6883cba32d9fd477251889a1c58081..d6e5ba3399f0ae151ea040e2ec1fd1df1c3dba6a 100644 (file)
--- a/block/bio.c
+++ b/block/bio.c
@@ -1831,8 +1831,9 @@ EXPORT_SYMBOL(bio_endio);
  * Allocates and returns a new bio which represents @sectors from the start of
  * @bio, and updates @bio to represent the remaining sectors.
  *
- * The newly allocated bio will point to @bio's bi_io_vec; it is the caller's
- * responsibility to ensure that @bio is not freed before the split.
+ * Unless this is a discard request the newly allocated bio will point
+ * to @bio's bi_io_vec; it is the caller's responsibility to ensure that
+ * @bio is not freed before the split.
  */
 struct bio *bio_split(struct bio *bio, int sectors,
                      gfp_t gfp, struct bio_set *bs)
@@ -1842,7 +1843,15 @@ struct bio *bio_split(struct bio *bio, int sectors,
        BUG_ON(sectors <= 0);
        BUG_ON(sectors >= bio_sectors(bio));
 
-       split = bio_clone_fast(bio, gfp, bs);
+       /*
+        * Discards need a mutable bio_vec to accommodate the payload
+        * required by the DSM TRIM and UNMAP commands.
+        */
+       if (bio->bi_rw & REQ_DISCARD)
+               split = bio_clone_bioset(bio, gfp, bs);
+       else
+               split = bio_clone_fast(bio, gfp, bs);
+
        if (!split)
                return NULL;
 
@@ -2009,6 +2018,7 @@ int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css)
        bio->bi_css = blkcg_css;
        return 0;
 }
+EXPORT_SYMBOL_GPL(bio_associate_blkcg);
 
 /**
  * bio_associate_current - associate a bio with %current
@@ -2039,6 +2049,7 @@ int bio_associate_current(struct bio *bio)
        bio->bi_css = task_get_css(current, blkio_cgrp_id);
        return 0;
 }
+EXPORT_SYMBOL_GPL(bio_associate_current);
 
 /**
  * bio_disassociate_task - undo bio_associate_current()