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-rw-r--r--block/bio.c17
1 files changed, 14 insertions, 3 deletions
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()