Merge tag 'trace-fixes-v3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/rosted...

[deliverable/linux.git] / drivers / md / dm-bufio.c

diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index c6083132c4b8ccaf21c7addb61cf8596165bf915..0387e05cdb98b9708bde55143cd8a5cba853a2fa 100644 (file)
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -319,6 +319,9 @@ static void __cache_size_refresh(void)
 static void *alloc_buffer_data(struct dm_bufio_client *c, gfp_t gfp_mask,
                               enum data_mode *data_mode)
 {
+       unsigned noio_flag;
+       void *ptr;
+
        if (c->block_size <= DM_BUFIO_BLOCK_SIZE_SLAB_LIMIT) {
                *data_mode = DATA_MODE_SLAB;
                return kmem_cache_alloc(DM_BUFIO_CACHE(c), gfp_mask);
@@ -332,7 +335,26 @@ static void *alloc_buffer_data(struct dm_bufio_client *c, gfp_t gfp_mask,
        }
 
        *data_mode = DATA_MODE_VMALLOC;
-       return __vmalloc(c->block_size, gfp_mask, PAGE_KERNEL);
+
+       /*
+        * __vmalloc allocates the data pages and auxiliary structures with
+        * gfp_flags that were specified, but pagetables are always allocated
+        * with GFP_KERNEL, no matter what was specified as gfp_mask.
+        *
+        * Consequently, we must set per-process flag PF_MEMALLOC_NOIO so that
+        * all allocations done by this process (including pagetables) are done
+        * as if GFP_NOIO was specified.
+        */
+
+       if (gfp_mask & __GFP_NORETRY)
+               noio_flag = memalloc_noio_save();
+
+       ptr = __vmalloc(c->block_size, gfp_mask, PAGE_KERNEL);
+
+       if (gfp_mask & __GFP_NORETRY)
+               memalloc_noio_restore(noio_flag);
+
+       return ptr;
 }
 
 /*