1 files changed, 15 insertions, 9 deletions

diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index ee7646f974a0..789bf535d29c 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -22,6 +22,7 @@
 #include <linux/blkdev.h>
 #include <linux/raid/md_u.h>
 #include <linux/seq_file.h>
+#include <linux/slab.h>
 #include "md.h"
 #include "multipath.h"
 
@@ -145,7 +146,7 @@ static int multipath_make_request (struct request_queue *q, struct bio * bio)
         int cpu;
 
         if (unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER))) {
-                bio_endio(bio, -EOPNOTSUPP);
+                md_barrier_request(mddev, bio);
                 return 0;
         }
 
@@ -301,14 +302,16 @@ static int multipath_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
                                           rdev->data_offset << 9);
 
                 /* as we don't honour merge_bvec_fn, we must never risk
-                 * violating it, so limit ->max_sector to one PAGE, as
-                 * a one page request is never in violation.
+                 * violating it, so limit ->max_segments to one, lying
+                 * within a single page.
                  * (Note: it is very unlikely that a device with
                  * merge_bvec_fn will be involved in multipath.)
                  */
-                        if (q->merge_bvec_fn &&
-                            queue_max_sectors(q) > (PAGE_SIZE>>9))
-                                blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
+                        if (q->merge_bvec_fn) {
+                                blk_queue_max_segments(mddev->queue, 1);
+                                blk_queue_segment_boundary(mddev->queue,
+                                                           PAGE_CACHE_SIZE - 1);
+                        }
 
                         conf->working_disks++;
                         mddev->degraded--;
@@ -476,9 +479,11 @@ static int multipath_run (mddev_t *mddev)
                 /* as we don't honour merge_bvec_fn, we must never risk
                  * violating it, not that we ever expect a device with
                  * a merge_bvec_fn to be involved in multipath */
-                if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
-                    queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9))
-                        blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
+                if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
+                        blk_queue_max_segments(mddev->queue, 1);
+                        blk_queue_segment_boundary(mddev->queue,
+                                                   PAGE_CACHE_SIZE - 1);
+                }
 
                 if (!test_bit(Faulty, &rdev->flags))
                         conf->working_disks++;
@@ -581,6 +586,7 @@ static void __exit multipath_exit (void)
 module_init(multipath_init);
 module_exit(multipath_exit);
 MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("simple multi-path personality for MD");
 MODULE_ALIAS("md-personality-7"); /* MULTIPATH */
 MODULE_ALIAS("md-multipath");
 MODULE_ALIAS("md-level--4");