linux-kernel - [PATCH] z3fold: fix sheduling while atomic

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Message-Id: <20190523153245.119dfeed55927e8755250ddd@gmail.com>
Date:   Thu, 23 May 2019 15:32:45 +0200
From:   Vitaly Wool <vitalywool@...il.com>
To:     Linux-MM <linux-mm@...ck.org>, linux-kernel@...r.kernel.org
Cc:     Dan Streetman <ddstreet@...e.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Oleksiy.Avramchenko@...y.com,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Subject: [PATCH] z3fold: fix sheduling while atomic

kmem_cache_alloc() may be called from z3fold_alloc() in atomic
context, so we need to pass correct gfp flags to avoid "scheduling
while atomic" bug.

Signed-off-by: Vitaly Wool <vitaly.vul@...y.com>
---
 mm/z3fold.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/mm/z3fold.c b/mm/z3fold.c
index 99be52c5ca45..985732c8b025 100644
--- a/mm/z3fold.c
+++ b/mm/z3fold.c
@@ -190,10 +190,11 @@ static int size_to_chunks(size_t size)
 
 static void compact_page_work(struct work_struct *w);
 
-static inline struct z3fold_buddy_slots *alloc_slots(struct z3fold_pool *pool)
+static inline struct z3fold_buddy_slots *alloc_slots(struct z3fold_pool *pool,
+							gfp_t gfp)
 {
 	struct z3fold_buddy_slots *slots = kmem_cache_alloc(pool->c_handle,
-							GFP_KERNEL);
+							    gfp);
 
 	if (slots) {
 		memset(slots->slot, 0, sizeof(slots->slot));
@@ -295,10 +296,10 @@ static void z3fold_unregister_migration(struct z3fold_pool *pool)
 
 /* Initializes the z3fold header of a newly allocated z3fold page */
 static struct z3fold_header *init_z3fold_page(struct page *page,
-					struct z3fold_pool *pool)
+					struct z3fold_pool *pool, gfp_t gfp)
 {
 	struct z3fold_header *zhdr = page_address(page);
-	struct z3fold_buddy_slots *slots = alloc_slots(pool);
+	struct z3fold_buddy_slots *slots = alloc_slots(pool, gfp);
 
 	if (!slots)
 		return NULL;
@@ -912,7 +913,7 @@ static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp,
 	if (!page)
 		return -ENOMEM;
 
-	zhdr = init_z3fold_page(page, pool);
+	zhdr = init_z3fold_page(page, pool, gfp);
 	if (!zhdr) {
 		__free_page(page);
 		return -ENOMEM;
-- 
2.17.1