path: root/ipc
diff options
authorEric W. Biederman <ebiederm@xmission.com>2018-09-25 11:27:20 +0200
committerEric W. Biederman <ebiederm@xmission.com>2018-10-03 16:47:43 +0200
commitae7795bc6187a15ec51cf258abae656a625f9980 (patch)
tree2456aa85c6b4be1ac58e272393056c0edbee038a /ipc
parent4cd2e0e70af6897ca2247fa1ffb1553ca16b4903 (diff)
signal: Distinguish between kernel_siginfo and siginfo
Linus recently observed that if we did not worry about the padding member in struct siginfo it is only about 48 bytes, and 48 bytes is much nicer than 128 bytes for allocating on the stack and copying around in the kernel. The obvious thing of only adding the padding when userspace is including siginfo.h won't work as there are sigframe definitions in the kernel that embed struct siginfo. So split siginfo in two; kernel_siginfo and siginfo. Keeping the traditional name for the userspace definition. While the version that is used internally to the kernel and ultimately will not be padded to 128 bytes is called kernel_siginfo. The definition of struct kernel_siginfo I have put in include/signal_types.h A set of buildtime checks has been added to verify the two structures have the same field offsets. To make it easy to verify the change kernel_siginfo retains the same size as siginfo. The reduction in size comes in a following change. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'ipc')
1 files changed, 1 insertions, 1 deletions
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index c0d58f390c3b..cc41de3b8deb 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -655,7 +655,7 @@ static void __do_notify(struct mqueue_inode_info *info)
* synchronously. */
if (info->notify_owner &&
info->attr.mq_curmsgs == 1) {
- struct siginfo sig_i;
+ struct kernel_siginfo sig_i;
switch (info->notify.sigev_notify) {

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