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[PATCH] posix: Add p{read,write}v2 RWF_NOWAIT flag (BZ#21738)
- From: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>
- To: libc-alpha at sourceware dot org
- Date: Mon, 10 Jul 2017 16:24:45 -0300
- Subject: [PATCH] posix: Add p{read,write}v2 RWF_NOWAIT flag (BZ#21738)
- Authentication-results: sourceware.org; auth=none
Linux 4.12 (b745fafaf70c0a98a2e1e7ac8cb14542889ceb0e) adds a new
p{read,write}v2 flag RWF_NOWAIT. This patch adds it for linux
uio-ext.h header along with RWF_SUPPORTED (a mask with all supported
flags).
Checked on x86_64-linux-gnu (on a 4.10 kernel).
[BZ #21738]
* manual/llio.texi (RWF_NOWAIT): New item.
(RWF_SUPPORTED): Likewise.
* misc/tst-preadvwritev2-common.c (do_test_with_invalid_flags):
Create an invalid flag from RWF_SUPPORTED definition.
* sysdeps/unix/sysv/linux/bits/uio-ext.h (RWF_NOWAIT): New flag.
(RWF_SUPPORTED): Likewise.
---
ChangeLog | 10 ++++++++++
manual/llio.texi | 6 ++++++
misc/tst-preadvwritev2-common.c | 14 ++++----------
sysdeps/unix/sysv/linux/bits/uio-ext.h | 4 ++++
4 files changed, 24 insertions(+), 10 deletions(-)
diff --git a/manual/llio.texi b/manual/llio.texi
index ba1f455..1aab522 100644
--- a/manual/llio.texi
+++ b/manual/llio.texi
@@ -770,6 +770,12 @@ Per-IO synchronization as if the file was opened with @code{O_DSYNC} flag.
@item RWF_SYNC
Per-IO synchronization as if the file was opened with @code{O_SYNC} flag.
+
+@item RWF_NOWAIT
+Set @code{preadv2} to return -EAGAIN if operation would block.
+
+@item RWF_SUPPORTED
+Mask with all supported flags.
@end vtable
When the source file is compiled with @code{_FILE_OFFSET_BITS == 64} the
diff --git a/misc/tst-preadvwritev2-common.c b/misc/tst-preadvwritev2-common.c
index 4c53d56..91cd58d 100644
--- a/misc/tst-preadvwritev2-common.c
+++ b/misc/tst-preadvwritev2-common.c
@@ -16,21 +16,15 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
+#include <limits.h>
#include <support/check.h>
static void
do_test_with_invalid_flags (void)
{
- int invalid_flag = 0x1;
-#ifdef RWF_HIPRI
- invalid_flag <<= 1;
-#endif
-#ifdef RWF_DSYNC
- invalid_flag <<= 1;
-#endif
-#ifdef RWF_SYNC
- invalid_flag <<= 1;
-#endif
+ /* Set the next bit from the mask of all supported flags. */
+ int invalid_flag = __builtin_clz (RWF_SUPPORTED);
+ invalid_flag = 0x1 << ((sizeof (int) * CHAR_BIT) - invalid_flag);
char buf[32];
const struct iovec vec = { .iov_base = buf, .iov_len = sizeof (buf) };
diff --git a/sysdeps/unix/sysv/linux/bits/uio-ext.h b/sysdeps/unix/sysv/linux/bits/uio-ext.h
index 4ddb644..12cd78e 100644
--- a/sysdeps/unix/sysv/linux/bits/uio-ext.h
+++ b/sysdeps/unix/sysv/linux/bits/uio-ext.h
@@ -46,6 +46,10 @@ extern ssize_t process_vm_writev (pid_t __pid, const struct iovec *__lvec,
#define RWF_HIPRI 0x00000001 /* High priority request. */
#define RWF_DSYNC 0x00000002 /* per-IO O_DSYNC. */
#define RWF_SYNC 0x00000004 /* per-IO O_SYNC. */
+#define RWF_NOWAIT 0x00000008 /* per-IO, return -EAGAIN if operation
+ would block */
+#define RWF_SUPPORTED (RWF_HIPRI | RWF_DSYNC | RWF_SYNC | RWF_NOWAIT)
+
__END_DECLS
--
2.7.4