Check we're going to free a reasonable number of frags in token_count
before starting the loop, to prevent looping too long.
Also minor code cleanups:
- Flip checks to reduce indentation.
- Use sizeof(*tokens) everywhere for consistentcy.
Cc: Yi Lai <yi1....@linux.intel.com>
Signed-off-by: Mina Almasry <almasrym...@google.com>
---
net/core/sock.c | 46 ++++++++++++++++++++++++++++------------------
1 file changed, 28 insertions(+), 18 deletions(-)
diff --git a/net/core/sock.c b/net/core/sock.c
index 7f398bd07fb7..8603b8d87f2e 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1047,11 +1047,12 @@ static int sock_reserve_memory(struct sock *sk, int
bytes)
#ifdef CONFIG_PAGE_POOL
-/* This is the number of tokens that the user can SO_DEVMEM_DONTNEED in
+/* This is the number of frags that the user can SO_DEVMEM_DONTNEED in
* 1 syscall. The limit exists to limit the amount of memory the kernel
- * allocates to copy these tokens.
+ * allocates to copy these tokens, and to prevent looping over the frags for
+ * too long.
*/
-#define MAX_DONTNEED_TOKENS 128
+#define MAX_DONTNEED_FRAGS 1024
static noinline_for_stack int
sock_devmem_dontneed(struct sock *sk, sockptr_t optval, unsigned int optlen)
@@ -1059,43 +1060,52 @@ sock_devmem_dontneed(struct sock *sk, sockptr_t optval,
unsigned int optlen)
unsigned int num_tokens, i, j, k, netmem_num = 0;
struct dmabuf_token *tokens;
netmem_ref netmems[16];
+ u64 num_frags = 0;
int ret = 0;
if (!sk_is_tcp(sk))
return -EBADF;
- if (optlen % sizeof(struct dmabuf_token) ||
- optlen > sizeof(*tokens) * MAX_DONTNEED_TOKENS)
+ if (optlen % sizeof(*tokens) ||
+ optlen > sizeof(*tokens) * MAX_DONTNEED_FRAGS)
return -EINVAL;
- tokens = kvmalloc_array(optlen, sizeof(*tokens), GFP_KERNEL);
+ num_tokens = optlen / sizeof(*tokens);
+ tokens = kvmalloc_array(num_tokens, sizeof(*tokens), GFP_KERNEL);
if (!tokens)
return -ENOMEM;
- num_tokens = optlen / sizeof(struct dmabuf_token);
if (copy_from_sockptr(tokens, optval, optlen)) {
kvfree(tokens);
return -EFAULT;
}
+ for (i = 0; i < num_tokens; i++) {
+ num_frags += tokens[i].token_count;
+ if (num_frags > MAX_DONTNEED_FRAGS) {
+ kvfree(tokens);
+ return -E2BIG;
+ }
+ }
+
xa_lock_bh(&sk->sk_user_frags);
for (i = 0; i < num_tokens; i++) {
for (j = 0; j < tokens[i].token_count; j++) {
netmem_ref netmem = (__force netmem_ref)__xa_erase(
&sk->sk_user_frags, tokens[i].token_start + j);
- if (netmem &&
- !WARN_ON_ONCE(!netmem_is_net_iov(netmem))) {
- netmems[netmem_num++] = netmem;
- if (netmem_num == ARRAY_SIZE(netmems)) {
- xa_unlock_bh(&sk->sk_user_frags);
- for (k = 0; k < netmem_num; k++)
-
WARN_ON_ONCE(!napi_pp_put_page(netmems[k]));
- netmem_num = 0;
- xa_lock_bh(&sk->sk_user_frags);
- }
- ret++;
+ if (!netmem || WARN_ON_ONCE(!netmem_is_net_iov(netmem)))
+ continue;
+
+ netmems[netmem_num++] = netmem;
+ if (netmem_num == ARRAY_SIZE(netmems)) {
+ xa_unlock_bh(&sk->sk_user_frags);
+ for (k = 0; k < netmem_num; k++)
+
WARN_ON_ONCE(!napi_pp_put_page(netmems[k]));
+ netmem_num = 0;
+ xa_lock_bh(&sk->sk_user_frags);
}
+ ret++;
}
}
--
2.47.0.163.g1226f6d8fa-goog
