diff mbox series

[bpf-next,3/9] bpf: Refactor the core bpf_task_storage_get logic into a new function

Message ID 20221025184524.3526117-4-martin.lau@linux.dev (mailing list archive)
State Accepted
Commit 6d65500c34d897329ed1be0fd3c4014ec52cd473
Delegated to: BPF
Headers show
Series bpf: Avoid unnecessary deadlock detection and failure in task storage | expand

Checks

Context Check Description
bpf/vmtest-bpf-next-PR success PR summary
netdev/tree_selection success Clearly marked for bpf-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 2 this patch: 2
netdev/cc_maintainers warning 7 maintainers not CCed: sdf@google.com john.fastabend@gmail.com yhs@fb.com haoluo@google.com jolsa@kernel.org kpsingh@kernel.org song@kernel.org
netdev/build_clang success Errors and warnings before: 5 this patch: 5
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 2 this patch: 2
netdev/checkpatch warning WARNING: line length of 83 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
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Commit Message

Martin KaFai Lau Oct. 25, 2022, 6:45 p.m. UTC 
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 mbox series

Patch

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 *,