From 6d65500c34d897329ed1be0fd3c4014ec52cd473 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Tue, 25 Oct 2022 11:45:18 -0700 Subject: [PATCH] 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: Martin KaFai Lau Link: https://lore.kernel.org/r/20221025184524.3526117-4-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov --- kernel/bpf/bpf_task_storage.c | 48 ++++++++++++++++++++--------------- 1 file changed, 28 insertions(+), 20 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 @@ out: return err; } +/* 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; + + sdata = task_storage_lookup(task, map, true); + if (sdata) + return sdata->data; + + /* only allocate new storage, when the task is refcounted */ + if (refcount_read(&task->usage) && + (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; + } + + 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) { - struct bpf_local_storage_data *sdata; + void *data; WARN_ON_ONCE(!bpf_rcu_lock_held()); - if (flags & ~(BPF_LOCAL_STORAGE_GET_F_CREATE)) - return (unsigned long)NULL; - - if (!task) + if (flags & ~BPF_LOCAL_STORAGE_GET_F_CREATE || !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; - - /* only allocate new storage, when the task is refcounted */ - if (refcount_read(&task->usage) && - (flags & BPF_LOCAL_STORAGE_GET_F_CREATE)) - sdata = bpf_local_storage_update( - task, (struct bpf_local_storage_map *)map, value, - BPF_NOEXIST, gfp_flags); - -unlock: + 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 *,