drivers/md/dm-ioctl.c: use kvmalloc rather than opencoded variant

copy_params uses kmalloc with vmalloc fallback.  We already have a
helper for that - kvmalloc.  This caller requires GFP_NOIO semantic so
it hasn't been converted with many others by previous patches.  All we
need to achieve this semantic is to use the scope
memalloc_noio_{save,restore} around kvmalloc.

Link: http://lkml.kernel.org/r/20170306103327.2766-4-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 9 deletions

diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index 2d5d7064acbf..0555b4410e05 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1691,6 +1691,7 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kern
         struct dm_ioctl *dmi;
         int secure_data;
         const size_t minimum_data_size = offsetof(struct dm_ioctl, data);
+        unsigned noio_flag;
 
         if (copy_from_user(param_kernel, user, minimum_data_size))
                 return -EFAULT;
@@ -1713,15 +1714,9 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kern
          * Use kmalloc() rather than vmalloc() when we can.
          */
         dmi = NULL;
-        if (param_kernel->data_size <= KMALLOC_MAX_SIZE)
-                dmi = kmalloc(param_kernel->data_size, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
-
-        if (!dmi) {
-                unsigned noio_flag;
-                noio_flag = memalloc_noio_save();
-                dmi = __vmalloc(param_kernel->data_size, GFP_NOIO | __GFP_HIGH | __GFP_HIGHMEM, PAGE_KERNEL);
-                memalloc_noio_restore(noio_flag);
-        }
+        noio_flag = memalloc_noio_save();
+        dmi = kvmalloc(param_kernel->data_size, GFP_KERNEL);
+        memalloc_noio_restore(noio_flag);
 
         if (!dmi) {
                 if (secure_data && clear_user(user, param_kernel->data_size))