dm ioctl: restore __GFP_HIGH in copy_params()

Commit d224e93 ("drivers/md/dm-ioctl.c: use kvmalloc rather than
opencoded variant") left out the __GFP_HIGH flag when converting from
__vmalloc to kvmalloc.  This can cause the DM ioctl to fail in some low
memory situations where it wouldn't have failed earlier.  Add __GFP_HIGH
back to avoid any potential regression.

Fixes: d224e93 ("drivers/md/dm-ioctl.c: use kvmalloc rather than opencoded variant")
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-ioctl.c

@@ -1710,12 +1710,13 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kern
 	}
 
 	/*
-	 * Try to avoid low memory issues when a device is suspended.
+	 * Use __GFP_HIGH to avoid low memory issues when a device is
+	 * suspended and the ioctl is needed to resume it.
 	 * Use kmalloc() rather than vmalloc() when we can.
 	 */
 	dmi = NULL;
 	noio_flag = memalloc_noio_save();
-	dmi = kvmalloc(param_kernel->data_size, GFP_KERNEL);
+	dmi = kvmalloc(param_kernel->data_size, GFP_KERNEL | __GFP_HIGH);
 	memalloc_noio_restore(noio_flag);
 
 	if (!dmi) {