X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;f=block%2Fbio.c;h=d6e5ba3399f0ae151ea040e2ec1fd1df1c3dba6a;hb=3bd8f7d87dd12a97f0215f0d1a4afdd20ba49854;hp=2a00d349cd6883cba32d9fd477251889a1c58081;hpb=5c3950970b91df6a15db66ec4498bac9b12f4002;p=linux-2.6-block.git

diff --git a/block/bio.c b/block/bio.c
index 2a00d349cd68..d6e5ba3399f0 100644
--- 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()