1 files changed, 86 insertions, 0 deletions

diff --git a/recipes-kernel/linux/linux-ti33x-psp-3.2/3.2.10/0085-dm-io-fix-discard-support.patch b/recipes-kernel/linux/linux-ti33x-psp-3.2/3.2.10/0085-dm-io-fix-discard-support.patch
new file mode 100644
index 00000000..b5ff74ad
--- /dev/null
+++ b/recipes-kernel/linux/linux-ti33x-psp-3.2/3.2.10/0085-dm-io-fix-discard-support.patch
@@ -0,0 +1,86 @@
+From cf6db92080c563161f5626184902162432f5fac5 Mon Sep 17 00:00:00 2001
+From: Milan Broz <mbroz@redhat.com>
+Date: Wed, 7 Mar 2012 19:09:37 +0000
+Subject: [PATCH 85/95] dm io: fix discard support
+
+commit 0c535e0d6f463365c29623350dbd91642363c39b upstream.
+
+This patch fixes a crash by recognising discards in dm_io.
+
+Currently dm_mirror can send REQ_DISCARD bios if running over a
+discard-enabled device and without support in dm_io the system
+crashes badly.
+
+BUG: unable to handle kernel paging request at 00800000
+IP:  __bio_add_page.part.17+0xf5/0x1e0
+...
+ bio_add_page+0x56/0x70
+ dispatch_io+0x1cf/0x240 [dm_mod]
+ ? km_get_page+0x50/0x50 [dm_mod]
+ ? vm_next_page+0x20/0x20 [dm_mod]
+ ? mirror_flush+0x130/0x130 [dm_mirror]
+ dm_io+0xdc/0x2b0 [dm_mod]
+...
+
+Introduced in 2.6.38-rc1 by commit 5fc2ffeabb9ee0fc0e71ff16b49f34f0ed3d05b4
+(dm raid1: support discard).
+
+Signed-off-by: Milan Broz <mbroz@redhat.com>
+Acked-by: Mike Snitzer <snitzer@redhat.com>
+Signed-off-by: Alasdair G Kergon <agk@redhat.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/md/dm-io.c |   23 ++++++++++++++++-------
+ 1 file changed, 16 insertions(+), 7 deletions(-)
+
+diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
+index ad2eba4..ea5dd28 100644
+--- a/drivers/md/dm-io.c
++++ b/drivers/md/dm-io.c
+@@ -296,6 +296,8 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where,
+        unsigned offset;
+        unsigned num_bvecs;
+        sector_t remaining = where->count;
++       struct request_queue *q = bdev_get_queue(where->bdev);
++       sector_t discard_sectors;
+ 
+        /*
+         * where->count may be zero if rw holds a flush and we need to
+@@ -305,9 +307,12 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where,
+                /*
+                 * Allocate a suitably sized-bio.
+                 */
+-               num_bvecs = dm_sector_div_up(remaining,
+-                                            (PAGE_SIZE >> SECTOR_SHIFT));
+-               num_bvecs = min_t(int, bio_get_nr_vecs(where->bdev), num_bvecs);
++               if (rw & REQ_DISCARD)
++                       num_bvecs = 1;
++               else
++                       num_bvecs = min_t(int, bio_get_nr_vecs(where->bdev),
++                                         dm_sector_div_up(remaining, (PAGE_SIZE >> SECTOR_SHIFT)));
++
+                bio = bio_alloc_bioset(GFP_NOIO, num_bvecs, io->client->bios);
+                bio->bi_sector = where->sector + (where->count - remaining);
+                bio->bi_bdev = where->bdev;
+@@ -315,10 +320,14 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where,
+                bio->bi_destructor = dm_bio_destructor;
+                store_io_and_region_in_bio(bio, io, region);
+ 
+-               /*
+-                * Try and add as many pages as possible.
+-                */
+-               while (remaining) {
++               if (rw & REQ_DISCARD) {
++                       discard_sectors = min_t(sector_t, q->limits.max_discard_sectors, remaining);
++                       bio->bi_size = discard_sectors << SECTOR_SHIFT;
++                       remaining -= discard_sectors;
++               } else while (remaining) {
++                       /*
++                        * Try and add as many pages as possible.
++                        */
+                        dp->get_page(dp, &page, &len, &offset);
+                        len = min(len, to_bytes(remaining));
+                        if (!bio_add_page(bio, page, len, offset))
+-- 
+1.7.9.4
+