bpf.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: davem@davemloft.net
Cc: daniel@iogearbox.net, bpf@vger.kernel.org, kernel-team@fb.com
Subject: [PATCH v4 bpf-next 8/9] bpf: Allows per-cpu maps and map-in-map in sleepable programs
Date: Tue,  9 Feb 2021 19:36:33 -0800	[thread overview]
Message-ID: <20210210033634.62081-9-alexei.starovoitov@gmail.com> (raw)
In-Reply-To: <20210210033634.62081-1-alexei.starovoitov@gmail.com>

From: Alexei Starovoitov <ast@kernel.org>

Since sleepable programs are now executing under migrate_disable
the per-cpu maps are safe to use.
The map-in-map were ok to use in sleepable from the time sleepable
progs were introduced.

Note that non-preallocated maps are still not safe, since there is
no rcu_read_lock yet in sleepable programs and dynamically allocated
map elements are relying on rcu protection. The sleepable programs
have rcu_read_lock_trace instead. That limitation will be addresses
in the future.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: KP Singh <kpsingh@kernel.org>
---
 kernel/bpf/hashtab.c  | 4 ++--
 kernel/bpf/verifier.c | 7 ++++++-
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index c1ac7f964bc9..d63912e73ad9 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -1148,7 +1148,7 @@ static int __htab_percpu_map_update_elem(struct bpf_map *map, void *key,
 		/* unknown flags */
 		return -EINVAL;
 
-	WARN_ON_ONCE(!rcu_read_lock_held());
+	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held());
 
 	key_size = map->key_size;
 
@@ -1202,7 +1202,7 @@ static int __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
 		/* unknown flags */
 		return -EINVAL;
 
-	WARN_ON_ONCE(!rcu_read_lock_held());
+	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held());
 
 	key_size = map->key_size;
 
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 4189edb41b73..9561f2af7710 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -10020,9 +10020,14 @@ static int check_map_prog_compatibility(struct bpf_verifier_env *env,
 		case BPF_MAP_TYPE_HASH:
 		case BPF_MAP_TYPE_LRU_HASH:
 		case BPF_MAP_TYPE_ARRAY:
+		case BPF_MAP_TYPE_PERCPU_HASH:
+		case BPF_MAP_TYPE_PERCPU_ARRAY:
+		case BPF_MAP_TYPE_LRU_PERCPU_HASH:
+		case BPF_MAP_TYPE_ARRAY_OF_MAPS:
+		case BPF_MAP_TYPE_HASH_OF_MAPS:
 			if (!is_preallocated_map(map)) {
 				verbose(env,
-					"Sleepable programs can only use preallocated hash maps\n");
+					"Sleepable programs can only use preallocated maps\n");
 				return -EINVAL;
 			}
 			break;
-- 
2.24.1


  parent reply	other threads:[~2021-02-10  3:38 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-10  3:36 [PATCH v4 bpf-next 0/9] bpf: Misc improvements Alexei Starovoitov
2021-02-10  3:36 ` [PATCH v4 bpf-next 1/9] bpf: Optimize program stats Alexei Starovoitov
2021-02-12  3:26   ` Ilya Leoshkevich
2021-02-12  3:43     ` Alexei Starovoitov
2021-02-12  3:51       ` Ilya Leoshkevich
2021-02-10  3:36 ` [PATCH v4 bpf-next 2/9] bpf: Run sleepable programs with migration disabled Alexei Starovoitov
2021-02-10  3:36 ` [PATCH v4 bpf-next 3/9] bpf: Compute program stats for sleepable programs Alexei Starovoitov
2021-02-10  3:36 ` [PATCH v4 bpf-next 4/9] bpf: Add per-program recursion prevention mechanism Alexei Starovoitov
2021-02-10  3:36 ` [PATCH v4 bpf-next 5/9] selftest/bpf: Add a recursion test Alexei Starovoitov
2021-02-10  3:36 ` [PATCH v4 bpf-next 6/9] bpf: Count the number of times recursion was prevented Alexei Starovoitov
2021-02-10  3:36 ` [PATCH v4 bpf-next 7/9] selftests/bpf: Improve recursion selftest Alexei Starovoitov
2021-02-10  3:36 ` Alexei Starovoitov [this message]
2021-02-10  3:36 ` [PATCH v4 bpf-next 9/9] selftests/bpf: Add a test for map-in-map and per-cpu maps in sleepable progs Alexei Starovoitov
2021-02-11 15:30 ` [PATCH v4 bpf-next 0/9] bpf: Misc improvements patchwork-bot+netdevbpf

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210210033634.62081-9-alexei.starovoitov@gmail.com \
    --to=alexei.starovoitov@gmail.com \
    --cc=bpf@vger.kernel.org \
    --cc=daniel@iogearbox.net \
    --cc=davem@davemloft.net \
    --cc=kernel-team@fb.com \
    --subject='Re: [PATCH v4 bpf-next 8/9] bpf: Allows per-cpu maps and map-in-map in sleepable programs' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).