Merge branch 'Enable non-atomic allocations in local storage'

Joanne Koong says:

====================

From: Joanne Koong <joannelkoong@gmail.com>

Currently, local storage memory can only be allocated atomically
(GFP_ATOMIC). This restriction is too strict for sleepable bpf
programs.

In this patchset, sleepable programs can allocate memory in local
storage using GFP_KERNEL, while non-sleepable programs always default to
GFP_ATOMIC.

v3 <- v2:
* Add extra case to local_storage.c selftest to test associating multiple
elements with the local storage, which triggers a GFP_KERNEL allocation in
local_storage_update().
* Cast gfp_t to __s32 in verifier to fix the sparse warnings

v2 <- v1:
* Allocate the memory before/after the raw_spin_lock_irqsave, depending
on the gfp flags
* Rename mem_flags to gfp_flags
* Reword the comment "*mem_flags* is set by the bpf verifier" to
"*gfp_flags* is a hidden argument provided by the verifier"
* Add a sentence to the commit message about existing local storage
selftests covering both the GFP_ATOMIC and GFP_KERNEL paths in
bpf_local_storage_update.
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 19 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/progs/local_storage.c b/tools/testing/selftests/bpf/progs/local_storage.c
index 9b1f9b75d5c2..19423ed862e3 100644
--- a/tools/testing/selftests/bpf/progs/local_storage.c
+++ b/tools/testing/selftests/bpf/progs/local_storage.c
@@ -37,6 +37,13 @@ struct {
 } sk_storage_map SEC(".maps");
 
 struct {
+	__uint(type, BPF_MAP_TYPE_SK_STORAGE);
+	__uint(map_flags, BPF_F_NO_PREALLOC | BPF_F_CLONE);
+	__type(key, int);
+	__type(value, struct local_storage);
+} sk_storage_map2 SEC(".maps");
+
+struct {
 	__uint(type, BPF_MAP_TYPE_TASK_STORAGE);
 	__uint(map_flags, BPF_F_NO_PREALLOC);
 	__type(key, int);
@@ -115,7 +122,19 @@ int BPF_PROG(socket_bind, struct socket *sock, struct sockaddr *address,
 	if (storage->value != DUMMY_STORAGE_VALUE)
 		sk_storage_result = -1;
 
+	/* This tests that we can associate multiple elements
+	 * with the local storage.
+	 */
+	storage = bpf_sk_storage_get(&sk_storage_map2, sock->sk, 0,
+				     BPF_LOCAL_STORAGE_GET_F_CREATE);
+	if (!storage)
+		return 0;
+
 	err = bpf_sk_storage_delete(&sk_storage_map, sock->sk);
+	if (err)
+		return 0;
+
+	err = bpf_sk_storage_delete(&sk_storage_map2, sock->sk);
 	if (!err)
 		sk_storage_result = err;