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| author | Joanne Koong <joannelkoong@gmail.com> | 2022-03-17 21:55:52 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2022-03-20 18:55:05 -0700 |
| commit | b00fa38a9c1cba044a32a601b49a55a18ed719d1 (patch) | |
| tree | 871c74ded225f4bd7108f611a7a8e86f1642e16c /kernel/bpf/bpf_task_storage.c | |
| parent | a8fee96202e279441d0e52d83eb100bd4a6d6272 (diff) | |
| download | linux-b00fa38a9c1cba044a32a601b49a55a18ed719d1.tar.gz linux-b00fa38a9c1cba044a32a601b49a55a18ed719d1.tar.bz2 linux-b00fa38a9c1cba044a32a601b49a55a18ed719d1.zip | |
bpf: Enable non-atomic allocations in local storage
Currently, local storage memory can only be allocated atomically
(GFP_ATOMIC). This restriction is too strict for sleepable bpf
programs.
In this patch, the verifier detects whether the program is sleepable,
and passes the corresponding GFP_KERNEL or GFP_ATOMIC flag as a
5th argument to bpf_task/sk/inode_storage_get. This flag will propagate
down to the local storage functions that allocate memory.
Please note that bpf_task/sk/inode_storage_update_elem functions are
invoked by userspace applications through syscalls. Preemption is
disabled before bpf_task/sk/inode_storage_update_elem is called, which
means they will always have to allocate memory atomically.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: KP Singh <kpsingh@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220318045553.3091807-2-joannekoong@fb.com
Diffstat (limited to 'kernel/bpf/bpf_task_storage.c')
| -rw-r--r-- | kernel/bpf/bpf_task_storage.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/kernel/bpf/bpf_task_storage.c b/kernel/bpf/bpf_task_storage.c index 5da7bed0f5f6..6638a0ecc3d2 100644 --- a/kernel/bpf/bpf_task_storage.c +++ b/kernel/bpf/bpf_task_storage.c @@ -174,7 +174,8 @@ static int bpf_pid_task_storage_update_elem(struct bpf_map *map, void *key, bpf_task_storage_lock(); sdata = bpf_local_storage_update( - task, (struct bpf_local_storage_map *)map, value, map_flags); + task, (struct bpf_local_storage_map *)map, value, map_flags, + GFP_ATOMIC); bpf_task_storage_unlock(); err = PTR_ERR_OR_ZERO(sdata); @@ -226,8 +227,9 @@ out: return err; } -BPF_CALL_4(bpf_task_storage_get, struct bpf_map *, map, struct task_struct *, - task, void *, value, u64, flags) +/* *gfp_flags* is a hidden argument provided by the verifier */ +BPF_CALL_5(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; @@ -250,7 +252,7 @@ BPF_CALL_4(bpf_task_storage_get, struct bpf_map *, map, struct task_struct *, (flags & BPF_LOCAL_STORAGE_GET_F_CREATE)) sdata = bpf_local_storage_update( task, (struct bpf_local_storage_map *)map, value, - BPF_NOEXIST); + BPF_NOEXIST, gfp_flags); unlock: bpf_task_storage_unlock(); |