flag parameters: NONBLOCK in eventfd
This patch adds support for the EFD_NONBLOCK flag to eventfd2. The
additional changes needed are minimal.
The following test must be adjusted for architectures other than x86 and
x86-64 and in case the syscall numbers changed.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/syscall.h>
#ifndef __NR_eventfd2
# ifdef __x86_64__
# define __NR_eventfd2 290
# elif defined __i386__
# define __NR_eventfd2 328
# else
# error "need __NR_eventfd2"
# endif
#endif
#define EFD_NONBLOCK O_NONBLOCK
int
main (void)
{
int fd = syscall (__NR_eventfd2, 1, 0);
if (fd == -1)
{
puts ("eventfd2(0) failed");
return 1;
}
int fl = fcntl (fd, F_GETFL);
if (fl == -1)
{
puts ("fcntl failed");
return 1;
}
if (fl & O_NONBLOCK)
{
puts ("eventfd2(0) sets non-blocking mode");
return 1;
}
close (fd);
fd = syscall (__NR_eventfd2, 1, EFD_NONBLOCK);
if (fd == -1)
{
puts ("eventfd2(EFD_NONBLOCK) failed");
return 1;
}
fl = fcntl (fd, F_GETFL);
if (fl == -1)
{
puts ("fcntl failed");
return 1;
}
if ((fl & O_NONBLOCK) == 0)
{
puts ("eventfd2(EFD_NONBLOCK) does not set non-blocking mode");
return 1;
}
close (fd);
puts ("OK");
return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/eventfd.c b/fs/eventfd.c
index bd420e6..3ed4466 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -203,7 +203,7 @@
int fd;
struct eventfd_ctx *ctx;
- if (flags & ~EFD_CLOEXEC)
+ if (flags & ~(EFD_CLOEXEC | EFD_NONBLOCK))
return -EINVAL;
ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
@@ -218,7 +218,7 @@
* anon_inode_getfd() will install the fd.
*/
fd = anon_inode_getfd("[eventfd]", &eventfd_fops, ctx,
- flags & O_CLOEXEC);
+ flags & (O_CLOEXEC | O_NONBLOCK));
if (fd < 0)
kfree(ctx);
return fd;