Commit 6d65500c authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by Alexei Starovoitov
Browse files

bpf: Refactor the core bpf_task_storage_get logic into a new function 



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: default avatarMartin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20221025184524.3526117-4-martin.lau@linux.dev


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 0593dd34

kernel/bpf/bpf_task_storage.c

+26 −18
Original line number Diff line number Diff line
@@ -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 *,