From eb366989aa42e688b525929a0ff67ac047df7ee3 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Sun, 22 Apr 2018 18:23:47 +0200
Subject: [PATCH] dm/verity_fec: Use GFP aware reed solomon init
Git-commit: eb366989aa42e688b525929a0ff67ac047df7ee3
References: bsc#1111974
Patch-mainline: v4.18-rc1

Allocations from the rs_pool can invoke init_rs() from the mempool
allocation callback. This is problematic in fec_alloc_bufs() which invokes
mempool_alloc() with GFP_NOIO to prevent a swap deadlock because init_rs()
uses GFP_KERNEL allocations.

Switch it to init_rs_gfp() and invoke it with the gfp_t flags which are
handed in from the allocator.

Note: This is not a problem today because the rs control struct is shared
between the instances and its created when the mempool is initialized. But
the upcoming changes which switch to a rs_control struct per instance to
embed decoder buffers will trigger the swap vs. GFP_KERNEL issue.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Neil Brown <neilb@suse.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Coly Li <colyli@suse.de>

---
 drivers/md/dm-verity-fec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/dm-verity-fec.c b/drivers/md/dm-verity-fec.c
index e13f90832b6b..375453ef6f26 100644
--- a/drivers/md/dm-verity-fec.c
+++ b/drivers/md/dm-verity-fec.c
@@ -570,7 +570,7 @@ static void *fec_rs_alloc(gfp_t gfp_mask, void *pool_data)
 {
 	struct dm_verity *v = (struct dm_verity *)pool_data;
 
-	return init_rs(8, 0x11d, 0, 1, v->fec->roots);
+	return init_rs_gfp(8, 0x11d, 0, 1, v->fec->roots, gfp_mask);
 }
 
 static void fec_rs_free(void *element, void *pool_data)
-- 
2.19.0