From: Martin KaFai Lau <martin.lau@linux.dev>
To: bpf@vger.kernel.org
Cc: 'Alexei Starovoitov ' <ast@kernel.org>,
'Andrii Nakryiko ' <andrii@kernel.org>,
'Daniel Borkmann ' <daniel@iogearbox.net>,
'Song Liu ' <songliubraving@meta.com>,
kernel-team@meta.com
Subject: [PATCH bpf-next 3/9] bpf: Refactor the core bpf_task_storage_get logic into a new function
Date: Tue, 25 Oct 2022 11:45:18 -0700 [thread overview]
Message-ID: <20221025184524.3526117-4-martin.lau@linux.dev> (raw)
In-Reply-To: <20221025184524.3526117-1-martin.lau@linux.dev>
From: Martin KaFai Lau <martin.lau@kernel.org>
This patch creates a new function __bpf_task_storage_get() and
moves the core logic of the existing bpf_task_storage_get()
into this new function. This new function will be shared
by another new helper proto in the latter patch.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
---
kernel/bpf/bpf_task_storage.c | 44 +++++++++++++++++++++--------------
1 file changed, 26 insertions(+), 18 deletions(-)
diff --git a/kernel/bpf/bpf_task_storage.c b/kernel/bpf/bpf_task_storage.c
index bce50ae03f42..2726435e3eda 100644
--- a/kernel/bpf/bpf_task_storage.c
+++ b/kernel/bpf/bpf_task_storage.c
@@ -227,37 +227,45 @@ static int bpf_pid_task_storage_delete_elem(struct bpf_map *map, void *key)
return err;
}
-/* *gfp_flags* is a hidden argument provided by the verifier */
-BPF_CALL_5(bpf_task_storage_get_recur, struct bpf_map *, map, struct task_struct *,
- task, void *, value, u64, flags, gfp_t, gfp_flags)
+/* Called by bpf_task_storage_get*() helpers */
+static void *__bpf_task_storage_get(struct bpf_map *map,
+ struct task_struct *task, void *value,
+ u64 flags, gfp_t gfp_flags)
{
struct bpf_local_storage_data *sdata;
- WARN_ON_ONCE(!bpf_rcu_lock_held());
- if (flags & ~(BPF_LOCAL_STORAGE_GET_F_CREATE))
- return (unsigned long)NULL;
-
- if (!task)
- return (unsigned long)NULL;
-
- if (!bpf_task_storage_trylock())
- return (unsigned long)NULL;
-
sdata = task_storage_lookup(task, map, true);
if (sdata)
- goto unlock;
+ return sdata->data;
/* only allocate new storage, when the task is refcounted */
if (refcount_read(&task->usage) &&
- (flags & BPF_LOCAL_STORAGE_GET_F_CREATE))
+ (flags & BPF_LOCAL_STORAGE_GET_F_CREATE)) {
sdata = bpf_local_storage_update(
task, (struct bpf_local_storage_map *)map, value,
BPF_NOEXIST, gfp_flags);
+ return IS_ERR(sdata) ? NULL : sdata->data;
+ }
-unlock:
+ return NULL;
+}
+
+/* *gfp_flags* is a hidden argument provided by the verifier */
+BPF_CALL_5(bpf_task_storage_get_recur, struct bpf_map *, map, struct task_struct *,
+ task, void *, value, u64, flags, gfp_t, gfp_flags)
+{
+ void *data;
+
+ WARN_ON_ONCE(!bpf_rcu_lock_held());
+ if (flags & ~BPF_LOCAL_STORAGE_GET_F_CREATE || !task)
+ return (unsigned long)NULL;
+
+ if (!bpf_task_storage_trylock())
+ return (unsigned long)NULL;
+ data = __bpf_task_storage_get(map, task, value, flags,
+ gfp_flags);
bpf_task_storage_unlock();
- return IS_ERR_OR_NULL(sdata) ? (unsigned long)NULL :
- (unsigned long)sdata->data;
+ return (unsigned long)data;
}
BPF_CALL_2(bpf_task_storage_delete_recur, struct bpf_map *, map, struct task_struct *,
--
2.30.2
next prev parent reply other threads:[~2022-10-25 18:46 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-25 18:45 [PATCH bpf-next 0/9] bpf: Avoid unnecessary deadlock detection and failure in task storage Martin KaFai Lau
2022-10-25 18:45 ` [PATCH bpf-next 1/9] bpf: Remove prog->active check for bpf_lsm and bpf_iter Martin KaFai Lau
2022-10-25 18:45 ` [PATCH bpf-next 2/9] bpf: Append _recur naming to the bpf_task_storage helper proto Martin KaFai Lau
2022-10-25 18:45 ` Martin KaFai Lau [this message]
2022-10-25 18:45 ` [PATCH bpf-next 4/9] bpf: Avoid taking spinlock in bpf_task_storage_get if potential deadlock is detected Martin KaFai Lau
2022-10-25 18:45 ` [PATCH bpf-next 5/9] bpf: Add new bpf_task_storage_get proto with no deadlock detection Martin KaFai Lau
2022-10-25 18:45 ` [PATCH bpf-next 6/9] bpf: bpf_task_storage_delete_recur does lookup first before the deadlock check Martin KaFai Lau
2022-10-25 18:45 ` [PATCH bpf-next 7/9] bpf: Add new bpf_task_storage_delete proto with no deadlock detection Martin KaFai Lau
2022-10-25 18:45 ` [PATCH bpf-next 8/9] selftests/bpf: Ensure no task storage failure for bpf_lsm.s prog due to " Martin KaFai Lau
2022-10-25 18:45 ` [PATCH bpf-next 9/9] selftests/bpf: Tracing prog can still do lookup under busy lock Martin KaFai Lau
2022-10-26 6:20 ` [PATCH bpf-next 0/9] bpf: Avoid unnecessary deadlock detection and failure in task storage 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=20221025184524.3526117-4-martin.lau@linux.dev \
--to=martin.lau@linux.dev \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=kernel-team@meta.com \
--cc=songliubraving@meta.com \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox