diff options
| author | Minchan Kim <minchan@kernel.org> | 2013-01-30 11:41:39 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-06-07 16:02:06 -0700 |
| commit | 74eb879bd073a9a40b7f33ebc551b4510337b4e3 (patch) | |
| tree | c888ac4b7c553ead6141738dd8ba19e72d9954ec /drivers | |
| parent | 87dba703d0d9eb4352506dbd8f8878e3e2ee92f0 (diff) | |
zram: Fix deadlock bug in partial read/write
commit 7e5a5104c6af709a8d97d5f4711e7c917761d464 upstream.
Now zram allocates new page with GFP_KERNEL in zram I/O path
if IO is partial. Unfortunately, It may cause deadlock with
reclaim path like below.
write_page from fs
fs_lock
allocation(GFP_KERNEL)
reclaim
pageout
write_page from fs
fs_lock <-- deadlock
This patch fixes it by using GFP_NOIO. In read path, we
reorganize code flow so that kmap_atomic is called after the
GFP_NOIO allocation.
Acked-by: Jerome Marchand <jmarchand@redhat.com>
Acked-by: Nitin Gupta <ngupta@vflare.org>
[ penberg@kernel.org: don't use GFP_ATOMIC ]
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: no reordering is needed in the read path]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Jianguo Wu <wujianguo@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/staging/zram/zram_drv.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c index 685d612a627..fb7f9fb6d8b 100644 --- a/drivers/staging/zram/zram_drv.c +++ b/drivers/staging/zram/zram_drv.c @@ -235,7 +235,7 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, if (is_partial_io(bvec)) { /* Use a temporary buffer to decompress the page */ - uncmem = kmalloc(PAGE_SIZE, GFP_KERNEL); + uncmem = kmalloc(PAGE_SIZE, GFP_NOIO); if (!uncmem) { pr_info("Error allocating temp memory!\n"); return -ENOMEM; @@ -330,7 +330,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, * This is a partial IO. We need to read the full page * before to write the changes. */ - uncmem = kmalloc(PAGE_SIZE, GFP_KERNEL); + uncmem = kmalloc(PAGE_SIZE, GFP_NOIO); if (!uncmem) { pr_info("Error allocating temp memory!\n"); ret = -ENOMEM; |