bpf: Fix off-by-one error in bpf_mem_cache_idx()

[ Upstream commit 36024d023d139a0c8b552dc3b7f4dc7b4c139e8f ]

According to the definition of sizes[NUM_CACHES], when the size passed
to bpf_mem_cache_size() is 256, it should return 6 instead 7.

Fixes: bfb90de6b522 ("bpf: Introduce any context BPF specific memory allocator.")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20230118084630.3750680-1-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c
index 4901fa1048cd70e19ed0a07a9b59ef47d328e177..6187c28d266f01589894a39edff7131867d62630 100644 (file)
--- a/kernel/bpf/memalloc.c
+++ b/kernel/bpf/memalloc.c
@@ -71,7 +71,7 @@ static int bpf_mem_cache_idx(size_t size)
        if (size <= 192)
                return size_index[(size - 1) / 8] - 1;
 
-       return fls(size - 1) - 1;
+       return fls(size - 1) - 2;
 }
 
 #define NUM_CACHES 11