Merge tag ‘for-5.1-rc6-tag’ of git:// [Linux 5.1]

Merge tag ‘for-5.1-rc6-tag’ of git:// [Linux 5.1]

This Linux kernel change "Merge tag ‘for-5.1-rc6-tag’ of git://" is included in the Linux 5.1 release. This change is authored by Linus Torvalds <torvalds [at]> on Fri Apr 26 09:46:46 2019 -0700. The commit for this change in Linux stable tree is d0473f9 (patch). Other info about this change: Merge: 5813023 a3d46ae

Merge tag 'for-5.1-rc6-tag' of git://

Pull btrfs fix from David Sterba:
 "One patch to fix a crash in io submission path, due to memory
  allocation errors.

  In short, the multipage bio work that landed in 5.1 caused larger bios
  that in turn require larger temporary memory for checksums. The patch
  is a workaround, we're going to rework the allocation so it does not
  require the vmalloc fallback.

  It took a while to identify that it's caused by patches in 5.1 and not
  a patchset that did some changes in error handling in the code. I've
  tested it on various memory/cpu combinations, it could hit OOM but
  does not crash.

  The timestamp of the patch is less than a day due to updates in the
  changelog, tests were running meanwhile"

* tag 'for-5.1-rc6-tag' of git://
  btrfs: Switch memory allocations in async csum calculation path to kvmalloc

There is no are 0 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 fs/btrfs/file-item.c    | 15 +++++++++++----
 fs/btrfs/ordered-data.c |  3 ++-
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 920bf3b..cccc75d 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -7,6 +7,7 @@
 #include <linux/slab.h>
 #include <linux/pagemap.h>
 #include <linux/highmem.h>
+#include <linux/sched/mm.h>
 #include "ctree.h"
 #include "disk-io.h"
 #include "transaction.h"
@@ -427,9 +428,13 @@ blk_status_t btrfs_csum_one_bio(struct inode *inode, struct bio *bio,
    unsigned long this_sum_bytes = 0;
    int i;
    u64 offset;
+   unsigned nofs_flag;
+   nofs_flag = memalloc_nofs_save();
+   sums = kvzalloc(btrfs_ordered_sum_size(fs_info, bio->bi_iter.bi_size),
+              GFP_KERNEL);
+   memalloc_nofs_restore(nofs_flag);

-   sums = kzalloc(btrfs_ordered_sum_size(fs_info, bio->bi_iter.bi_size),
-              GFP_NOFS);
    if (!sums)
        return BLK_STS_RESOURCE;

@@ -472,8 +477,10 @@ blk_status_t btrfs_csum_one_bio(struct inode *inode, struct bio *bio,

                bytes_left = bio->bi_iter.bi_size - total_bytes;

-               sums = kzalloc(btrfs_ordered_sum_size(fs_info, bytes_left),
-                          GFP_NOFS);
+               nofs_flag = memalloc_nofs_save();
+               sums = kvzalloc(btrfs_ordered_sum_size(fs_info,
+                             bytes_left), GFP_KERNEL);
+               memalloc_nofs_restore(nofs_flag);
                BUG_ON(!sums); /* -ENOMEM */
                sums->len = bytes_left;
                ordered = btrfs_lookup_ordered_extent(inode,
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index 6fde2b2..45e3cfd 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -6,6 +6,7 @@
 #include <linux/slab.h>
 #include <linux/blkdev.h>
 #include <linux/writeback.h>
+#include <linux/sched/mm.h>
 #include "ctree.h"
 #include "transaction.h"
 #include "btrfs_inode.h"
@@ -442,7 +443,7 @@ void btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
            cur = entry->;
            sum = list_entry(cur, struct btrfs_ordered_sum, list);
-           kfree(sum);
+           kvfree(sum);
        kmem_cache_free(btrfs_ordered_extent_cache, entry);

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