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libbpf: Clean up ringbuf size adjustment implementation 

Drop unused iteration variable, move overflow prevention check into the
for loop.

Fixes: 0087a681fa ("libbpf: Automatically fix up BPF_MAP_TYPE_RINGBUF size, if necessary")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220510185159.754299-1-andrii@kernel.org
This commit is contained in:
Andrii Nakryiko 2022-05-10 11:51:59 -07:00 committed by Daniel Borkmann
parent 93dafa92e1
commit 5eefe17c7a
1 changed files with 2 additions and 4 deletions
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6
tools/lib/bpf/libbpf.c
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@ -4951,7 +4951,7 @@ static bool is_pow_of_2(size_t x)
static size_t adjust_ringbuf_sz(size_t sz)
{
__u32 page_sz = sysconf(_SC_PAGE_SIZE);
__u32 i, mul;
__u32 mul;
/* if user forgot to set any size, make sure they see error */
if (sz == 0)
@ -4967,9 +4967,7 @@ static size_t adjust_ringbuf_sz(size_t sz)
* user-set size to satisfy both user size request and kernel
* requirements and substitute correct max_entries for map creation.
*/
for (i = 0, mul = 1; ; i++, mul <<= 1) {
if (mul > UINT_MAX / page_sz) /* prevent __u32 overflow */
break;
for (mul = 1; mul <= UINT_MAX / page_sz; mul <<= 1) {
if (mul * page_sz > sz)
return mul * page_sz;
}