[PATCH bpf-next v5 6/7] mm: Make failslab, kfence, kmemleak aware of trylock mode

[Alexei Starovoitov <alexei.starovoitov@gmail.com>]

From: Alexei Starovoitov <ast@kernel.org>

When gfpflags_allow_spinning() == false spin_locks cannot be taken.
Make failslab, kfence, kmemleak compliant.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 mm/failslab.c    | 3 +++
 mm/kfence/core.c | 4 ++++
 mm/kmemleak.c    | 3 +++
 3 files changed, 10 insertions(+)

diff --git a/mm/failslab.c b/mm/failslab.c
index c3901b136498..86c7304ef25a 100644
--- a/mm/failslab.c
+++ b/mm/failslab.c
@@ -27,6 +27,9 @@ int should_failslab(struct kmem_cache *s, gfp_t gfpflags)
 	if (gfpflags & __GFP_NOFAIL)
 		return 0;
 
+	if (!gfpflags_allow_spinning(gfpflags))
+		return 0;
+
 	if (failslab.ignore_gfp_reclaim &&
 			(gfpflags & __GFP_DIRECT_RECLAIM))
 		return 0;
diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index 67fc321db79b..e5f2d63f3220 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -1096,6 +1096,10 @@ void *__kfence_alloc(struct kmem_cache *s, size_t size, gfp_t flags)
 	if (s->flags & SLAB_SKIP_KFENCE)
 		return NULL;
 
+	/* Bailout, since kfence_guarded_alloc() needs to take a lock */
+	if (!gfpflags_allow_spinning(flags))
+		return NULL;
+
 	allocation_gate = atomic_inc_return(&kfence_allocation_gate);
 	if (allocation_gate > 1)
 		return NULL;
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 2a945c07ae99..64cb44948e9e 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -648,6 +648,9 @@ static struct kmemleak_object *__alloc_object(gfp_t gfp)
 {
 	struct kmemleak_object *object;
 
+	if (!gfpflags_allow_spinning(gfp))
+		return NULL;
+
 	object = mem_pool_alloc(gfp);
 	if (!object) {
 		pr_warn("Cannot allocate a kmemleak_object structure\n");
-- 
2.43.5