[PATCH net-next] bpf: Fix compiler warning on info.map_ids for 32bit platform

[Martin KaFai Lau]

This patch uses u64_to_user_ptr() to cast info.map_ids to a userspace ptr.
It also tags the user_map_ids with '__user' for sparse check.

Fixes: cb4d2b3f03d8 ("bpf: Add name, load_time, uid and map_ids to 
bpf_prog_info")
Signed-off-by: Martin KaFai Lau <ka...@fb.com>
---
 kernel/bpf/syscall.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 11a7f82a55d1..b927da66f653 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1405,7 +1405,7 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
        info.nr_map_ids = prog->aux->used_map_cnt;
        ulen = min_t(u32, info.nr_map_ids, ulen);
        if (ulen) {
-               u32 *user_map_ids = (u32 *)info.map_ids;
+               u32 __user *user_map_ids = u64_to_user_ptr(info.map_ids);
                u32 i;
 
                for (i = 0; i < ulen; i++)
-- 
2.9.5