[PATCH] xen/blkfront: fix memory allocation flags in blkfront_setup_indirect()

[Juergen Gross <jgross@xxxxxxxx>]

Commit 1d5c76e664333 ("xen-blkfront: switch kcalloc to kvcalloc for
large array allocation") didn't fix the issue it was meant to, as the
flags for allocating the memory are GFP_NOIO, which will lead the
memory allocation falling back to kmalloc().

So instead of GFP_NOIO use GFP_KERNEL and do all the memory allocation
in blkfront_setup_indirect() in a memalloc_noio_{save,restore} section.

Fixes: 1d5c76e664333 ("xen-blkfront: switch kcalloc to kvcalloc for large array 
allocation")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 drivers/block/xen-blkfront.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 915cf5b6388c..3b889ea950c2 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -47,6 +47,7 @@
 #include <linux/bitmap.h>
 #include <linux/list.h>
 #include <linux/workqueue.h>
+#include <linux/sched/mm.h>
 
 #include <xen/xen.h>
 #include <xen/xenbus.h>
@@ -2189,10 +2190,12 @@ static void blkfront_setup_discard(struct blkfront_info 
*info)
 
 static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo)
 {
-       unsigned int psegs, grants;
+       unsigned int psegs, grants, memflags;
        int err, i;
        struct blkfront_info *info = rinfo->dev_info;
 
+       memflags = memalloc_noio_save();
+
        if (info->max_indirect_segments == 0) {
                if (!HAS_EXTRA_REQ)
                        grants = BLKIF_MAX_SEGMENTS_PER_REQUEST;
@@ -2224,7 +2227,7 @@ static int blkfront_setup_indirect(struct 
blkfront_ring_info *rinfo)
 
                BUG_ON(!list_empty(&rinfo->indirect_pages));
                for (i = 0; i < num; i++) {
-                       struct page *indirect_page = alloc_page(GFP_NOIO);
+                       struct page *indirect_page = alloc_page(GFP_KERNEL);
                        if (!indirect_page)
                                goto out_of_memory;
                        list_add(&indirect_page->lru, &rinfo->indirect_pages);
@@ -2235,15 +2238,15 @@ static int blkfront_setup_indirect(struct 
blkfront_ring_info *rinfo)
                rinfo->shadow[i].grants_used =
                        kvcalloc(grants,
                                 sizeof(rinfo->shadow[i].grants_used[0]),
-                                GFP_NOIO);
+                                GFP_KERNEL);
                rinfo->shadow[i].sg = kvcalloc(psegs,
                                               sizeof(rinfo->shadow[i].sg[0]),
-                                              GFP_NOIO);
+                                              GFP_KERNEL);
                if (info->max_indirect_segments)
                        rinfo->shadow[i].indirect_grants =
                                kvcalloc(INDIRECT_GREFS(grants),
                                         
sizeof(rinfo->shadow[i].indirect_grants[0]),
-                                        GFP_NOIO);
+                                        GFP_KERNEL);
                if ((rinfo->shadow[i].grants_used == NULL) ||
                        (rinfo->shadow[i].sg == NULL) ||
                     (info->max_indirect_segments &&
@@ -2252,6 +2255,7 @@ static int blkfront_setup_indirect(struct 
blkfront_ring_info *rinfo)
                sg_init_table(rinfo->shadow[i].sg, psegs);
        }
 
+       memalloc_noio_restore(memflags);
 
        return 0;
 
@@ -2271,6 +2275,9 @@ static int blkfront_setup_indirect(struct 
blkfront_ring_info *rinfo)
                        __free_page(indirect_page);
                }
        }
+
+       memalloc_noio_restore(memflags);
+
        return -ENOMEM;
 }
 
-- 
2.16.4