diff options
| author | Eric Dumazet <edumazet@google.com> | 2025-09-25 22:49:14 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-09-29 18:03:42 -0700 |
| commit | 2b235765e9d4426cf56d7fd1a331f81a4dbbd85a (patch) | |
| tree | 3fe7fd0baeb87b95cb3b6919ac1101cf92800104 | |
| parent | 3806446f609e111abf10b9a28c9e9762fafe56f4 (diff) | |
scm: use masked_user_access_begin() in put_cmsg()
Use the greatest and latest uaccess construct to get an optimal code.
Before :
lea (%r9,%rcx,1),%r10
movabs $<USER_PTR_MAX>,%r11
mov $0xfffffff2,%eax
cmp %rcx,%r10
jb ffffffff81cdc312 <put_cmsg+0x152>
cmp %r11,%r10
ja ffffffff81cdc312 <put_cmsg+0x152>
stac
lfence
mov %r9,(%rcx)
After:
movabs $<USER_PTR_MAX>,%r9
cmp %r9,%rax
cmova %r9,%rax
stac
mov %rcx,(%rax)
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250925224914.3590290-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/core/scm.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/net/core/scm.c b/net/core/scm.c index 072d5742440a..66eaee783e8b 100644 --- a/net/core/scm.c +++ b/net/core/scm.c @@ -273,7 +273,9 @@ int put_cmsg(struct msghdr * msg, int level, int type, int len, void *data) check_object_size(data, cmlen - sizeof(*cm), true); - if (!user_write_access_begin(cm, cmlen)) + if (can_do_masked_user_access()) + cm = masked_user_access_begin(cm); + else if (!user_write_access_begin(cm, cmlen)) goto efault; unsafe_put_user(cmlen, &cm->cmsg_len, efault_end); |