From: Vlastimil Babka (SUSE) Date: Wed, 10 Jun 2026 15:40:15 +0000 (+0200) Subject: mm/slab: allow __GFP_NOMEMALLOC and __GFP_NOWARN for kmalloc_nolock() X-Git-Url: http://git.ipfire.org/index.cgi?a=commitdiff_plain;h=6dbded46e447113da97bed4a68b02b8aaaffa995;p=thirdparty%2Fkernel%2Flinux.git mm/slab: allow __GFP_NOMEMALLOC and __GFP_NOWARN for kmalloc_nolock() The two flags are added internally so there's no point for warning if they are passed by the caller as well, so allow them. This will allow simplifying obj_ext allocation under kmalloc_nolock(). Also it's not necessary to have the extra alloc_gfp variable for adding the two flags. The original gfp_flags parameter is not used anywhere except for the warning. So remove alloc_gfp and directly modify and use gfp_flags everywhere. Link: https://patch.msgid.link/20260610-slab_alloc_flags-v2-13-7190909db118@kernel.org Reviewed-by: Hao Li Reviewed-by: Suren Baghdasaryan Reviewed-by: Harry Yoo (Oracle) Signed-off-by: Vlastimil Babka (SUSE) --- diff --git a/include/linux/slab.h b/include/linux/slab.h index ce1c867dc0ba8..b955f3cbb7328 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -1040,7 +1040,8 @@ void *_kmalloc_nolock_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t gfp_flags, in * kmalloc_nolock - Allocate an object of given size from any context. * @size: size to allocate * @gfp_flags: GFP flags. Only __GFP_ACCOUNT, __GFP_ZERO, __GFP_NO_OBJ_EXT - * allowed. + * allowed. Also __GFP_NOWARN and __GFP_NOMEMALLOC are allowed but added + * internally thus not necessary. * @node: node number of the target node. * * Return: pointer to the new object or NULL in case of error. diff --git a/mm/slub.c b/mm/slub.c index 537ea68f417b4..8769083bec818 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -5387,7 +5387,6 @@ EXPORT_SYMBOL(__kmalloc_noprof); void *_kmalloc_nolock_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t gfp_flags, int node) { - gfp_t alloc_gfp = __GFP_NOWARN | __GFP_NOMEMALLOC | gfp_flags; size_t orig_size = size; unsigned int alloc_flags = SLAB_ALLOC_NOLOCK; struct kmem_cache *s; @@ -5400,7 +5399,9 @@ void *_kmalloc_nolock_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t gfp_flags, in }; VM_WARN_ON_ONCE(gfp_flags & ~(__GFP_ACCOUNT | __GFP_ZERO | - __GFP_NO_OBJ_EXT)); + __GFP_NO_OBJ_EXT | __GFP_NOWARN | __GFP_NOMEMALLOC)); + + gfp_flags |= __GFP_NOWARN | __GFP_NOMEMALLOC; if (unlikely(!size)) return ZERO_SIZE_PTR; @@ -5419,7 +5420,7 @@ void *_kmalloc_nolock_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t gfp_flags, in retry: if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) return NULL; - s = kmalloc_slab(size, NULL, alloc_gfp, PASS_TOKEN_PARAM(token)); + s = kmalloc_slab(size, NULL, gfp_flags, PASS_TOKEN_PARAM(token)); if (!(s->flags & __CMPXCHG_DOUBLE) && !kmem_cache_debug(s)) /* @@ -5433,7 +5434,7 @@ retry: */ return NULL; - ret = alloc_from_pcs(s, alloc_gfp, alloc_flags, node); + ret = alloc_from_pcs(s, gfp_flags, alloc_flags, node); if (ret) goto success; @@ -5443,7 +5444,7 @@ retry: * kfence_alloc. Hence call __slab_alloc_node() (at most twice) * and slab_post_alloc_hook() directly. */ - ret = __slab_alloc_node(s, alloc_gfp, node, &ac); + ret = __slab_alloc_node(s, gfp_flags, node, &ac); /* * It's possible we failed due to trylock as we preempted someone with @@ -5456,8 +5457,8 @@ retry: size = s->object_size + 1; /* * Another alternative is to - * if (memcg) alloc_gfp &= ~__GFP_ACCOUNT; - * else if (!memcg) alloc_gfp |= __GFP_ACCOUNT; + * if (memcg) gfp_flags &= ~__GFP_ACCOUNT; + * else if (!memcg) gfp_flags |= __GFP_ACCOUNT; * to retry from bucket of the same size. */ can_retry = false; @@ -5466,9 +5467,9 @@ retry: success: maybe_wipe_obj_freeptr(s, ret); - slab_post_alloc_hook(s, alloc_gfp, 1, &ret, &ac); + slab_post_alloc_hook(s, gfp_flags, 1, &ret, &ac); - ret = kasan_kmalloc(s, ret, orig_size, alloc_gfp); + ret = kasan_kmalloc(s, ret, orig_size, gfp_flags); return ret; } EXPORT_SYMBOL_GPL(_kmalloc_nolock_noprof);