Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-12-24 03:42:52 +00:00
Code Issues Packages Projects Releases Wiki Activity

bpf: minor cleanups on fd maps and helpers

Browse Source 
Some minor cleanups: i) Remove the unlikely() from fd array map lookups
and let the CPU branch predictor do its job, scenarios where there is not
always a map entry are very well valid. ii) Move the attribute type check
in the bpf_perf_event_read() helper a bit earlier so it's consistent wrt
checks with bpf_perf_event_output() helper as well. iii) remove some
comments that are self-documenting in kprobe_prog_is_valid_access() and
therefore make it consistent to tp_prog_is_valid_access() as well.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Daniel Borkmann 2016-06-28 12:18:23 +02:00 committed by David S. Miller
parent ee58b57100
commit 1ca1cc98bf
2 changed files with 7 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
kernel/bpf/core.c
View File

@ -719,14 +719,13 @@ select_insn:
if (unlikely(index >= array->map.max_entries))
goto out;
if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT))
goto out;
tail_call_cnt++;
prog = READ_ONCE(array->ptrs[index]);
if (unlikely(!prog))
if (!prog)
goto out;
/* ARG1 at this point is guaranteed to point to CTX from

18
kernel/trace/bpf_trace.c
View File

@ -199,19 +199,19 @@ static u64 bpf_perf_event_read(u64 r1, u64 index, u64 r3, u64 r4, u64 r5)
return -E2BIG;
ee = READ_ONCE(array->ptrs[index]);
if (unlikely(!ee))
if (!ee)
return -ENOENT;
event = ee->event;
if (unlikely(event->attr.type != PERF_TYPE_HARDWARE &&
event->attr.type != PERF_TYPE_RAW))
return -EINVAL;
/* make sure event is local and doesn't have pmu::count */
if (event->oncpu != smp_processor_id() ||
event->pmu->count)
return -EINVAL;
if (unlikely(event->attr.type != PERF_TYPE_HARDWARE &&
event->attr.type != PERF_TYPE_RAW))
return -EINVAL;
/*
* we don't know if the function is run successfully by the
* return value. It can be judged in other places, such as
@ -251,7 +251,7 @@ static u64 bpf_perf_event_output(u64 r1, u64 r2, u64 flags, u64 r4, u64 size)
return -E2BIG;
ee = READ_ONCE(array->ptrs[index]);
if (unlikely(!ee))
if (!ee)
return -ENOENT;
event = ee->event;
@ -354,18 +354,12 @@ static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func
static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type type,
enum bpf_reg_type *reg_type)
{
/* check bounds */
if (off < 0 || off >= sizeof(struct pt_regs))
return false;
/* only read is allowed */
if (type != BPF_READ)
return false;
/* disallow misaligned access */
if (off % size != 0)
return false;
return true;
}