From: Christoph Hellwig <hch@lst.de>
Date: Tue, 12 Oct 2021 13:12:22 +0200
Subject: [PATCH] block: use SLAB_TYPESAFE_BY_RCU for the bio slab
Git-commit: 1a7e76e4f130332b5d3b0c72c4f664e59deb1239
Patch-mainline: v5.16-rc1
References: jsc#PED-1183

This flags ensures that the pages will not be reused for non-bio
allocations before the end of an RCU grace period.  With that we can
safely use a RCU lookup for bio polling as long as we are fine with
occasionally polling the wrong device.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
Link: https://lore.kernel.org/r/20211012111226.760968-13-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
 block/bio.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/block/bio.c b/block/bio.c
index d5120451c36a..df45f4b996ac 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -87,7 +87,8 @@ static struct bio_slab *create_bio_slab(unsigned int size)
 
 	snprintf(bslab->name, sizeof(bslab->name), "bio-%d", size);
 	bslab->slab = kmem_cache_create(bslab->name, size,
-			ARCH_KMALLOC_MINALIGN, SLAB_HWCACHE_ALIGN, NULL);
+			ARCH_KMALLOC_MINALIGN,
+			SLAB_HWCACHE_ALIGN | SLAB_TYPESAFE_BY_RCU, NULL);
 	if (!bslab->slab)
 		goto fail_alloc_slab;
 
-- 
2.35.3