diff options
| author | Eric Dumazet <edumazet@google.com> | 2025-09-25 23:09:29 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-09-29 18:04:37 -0700 |
| commit | 1fb0e471611dc6a79dee609a7e0037eb1d124400 (patch) | |
| tree | c9fcdae5a6802a158e9f085e964588267c6e60a5 /net | |
| parent | 2b235765e9d4426cf56d7fd1a331f81a4dbbd85a (diff) | |
net: remove one stac/clac pair from move_addr_to_user()
Convert the get_user() and __put_user() code to the
fast masked_user_access_begin()/unsafe_{get|put}_user()
variant.
This patch increases the performance of an UDP recvfrom()
receiver (netserver) on 120 bytes messages by 7 %
on an AMD EPYC 7B12 64-Core Processor platform.
Presence of audit_sockaddr() makes difficult
to avoid the stac/clac pair in the copy_to_user() call,
this is left for a future patch.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250925230929.3727873-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/socket.c | 35 |
1 files changed, 24 insertions, 11 deletions
diff --git a/net/socket.c b/net/socket.c index 682969deaed3..5bc4ee0bb75d 100644 --- a/net/socket.c +++ b/net/socket.c @@ -276,28 +276,41 @@ int move_addr_to_kernel(void __user *uaddr, int ulen, struct sockaddr_storage *k static int move_addr_to_user(struct sockaddr_storage *kaddr, int klen, void __user *uaddr, int __user *ulen) { - int err; int len; BUG_ON(klen > sizeof(struct sockaddr_storage)); - err = get_user(len, ulen); - if (err) - return err; + + if (can_do_masked_user_access()) + ulen = masked_user_access_begin(ulen); + else if (!user_access_begin(ulen, 4)) + return -EFAULT; + + unsafe_get_user(len, ulen, efault_end); + if (len > klen) len = klen; - if (len < 0) - return -EINVAL; + /* + * "fromlen shall refer to the value before truncation.." + * 1003.1g + */ + if (len >= 0) + unsafe_put_user(klen, ulen, efault_end); + + user_access_end(); + if (len) { + if (len < 0) + return -EINVAL; if (audit_sockaddr(klen, kaddr)) return -ENOMEM; if (copy_to_user(uaddr, kaddr, len)) return -EFAULT; } - /* - * "fromlen shall refer to the value before truncation.." - * 1003.1g - */ - return __put_user(klen, ulen); + return 0; + +efault_end: + user_access_end(); + return -EFAULT; } static struct kmem_cache *sock_inode_cachep __ro_after_init; |