From ba54d4d4d2844c234f1b4692bd8c9e0f833c8a54 Mon Sep 17 00:00:00 2001
From: Coly Li <colyli@suse.de>
Date: Thu, 9 Apr 2020 22:17:21 +0800
Subject: [PATCH] raid5: remove gfp flags from scribble_alloc()
Git-commit: ba54d4d4d2844c234f1b4692bd8c9e0f833c8a54
Patch-mainline: v5.8-rc1
References: bsc#1166985

Using GFP_NOIO flag to call scribble_alloc() from resize_chunk() does
not have the expected behavior. kvmalloc_array() inside scribble_alloc()
which receives the GFP_NOIO flag will eventually call kmalloc_node() to
allocate physically continuous pages.

Now we have memalloc scope APIs in mddev_suspend()/mddev_resume() to
prevent memory reclaim I/Os during raid array suspend context, calling
to kvmalloc_array() with GFP_KERNEL flag may avoid deadlock of recursive
I/O as expected.

This patch removes the useless gfp flags from parameters list of
scribble_alloc(), and call kvmalloc_array() with GFP_KERNEL flag. The
incorrect GFP_NOIO flag does not exist anymore.

(Coly Li: to avoid kabi breaking by adding noio_flag in struct mddev,
 commit 78f57ef9d50a is not backported and I modify this patch to use
 local noio_flag variable in scribble_alloc().)

Fixes: b330e6a49dc3 ("md: convert to kvmalloc")
Suggested-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Song Liu <songliubraving@fb.com>

---
 drivers/md/raid5.c |   15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -46,6 +46,7 @@
 #include <linux/slab.h>
 #include <linux/ratelimit.h>
 #include <linux/nodemask.h>
+#include <linux/sched/mm.h>
 
 #include <trace/events/block.h>
 #include <linux/list_sort.h>
@@ -2228,14 +2229,18 @@ static int grow_stripes(struct r5conf *c
  * of the P and Q blocks.
  */
 static int scribble_alloc(struct raid5_percpu *percpu,
-			  int num, int cnt, gfp_t flags)
+			  int num, int cnt)
 {
 	size_t obj_size =
 		sizeof(struct page *) * (num+2) +
 		sizeof(addr_conv_t) * (num+2);
 	void *scribble;
+	unsigned int noio_flag;
 
-	scribble = kvmalloc_array(cnt, obj_size, flags);
+	/* use local noio_flag to avoid kabi breaking */
+	noio_flag = memalloc_noio_save();
+	scribble = kvmalloc_array(cnt, obj_size, GFP_KERNEL);
+	memalloc_noio_restore(noio_flag);
 	if (!scribble)
 		return -ENOMEM;
 
@@ -2267,8 +2272,7 @@ static int resize_chunks(struct r5conf *
 
 		percpu = per_cpu_ptr(conf->percpu, cpu);
 		err = scribble_alloc(percpu, new_disks,
-				     new_sectors / STRIPE_SECTORS,
-				     GFP_NOIO);
+				     new_sectors / STRIPE_SECTORS);
 		if (err)
 			break;
 	}
@@ -6759,8 +6763,7 @@ static int alloc_scratch_buffer(struct r
 			       conf->previous_raid_disks),
 			   max(conf->chunk_sectors,
 			       conf->prev_chunk_sectors)
-			   / STRIPE_SECTORS,
-			   GFP_KERNEL)) {
+			   / STRIPE_SECTORS)) {
 		free_scratch_buffer(conf, percpu);
 		return -ENOMEM;
 	}