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authorAdhemerval Zanella <adhemerval.zanella@linaro.org>2017-07-10 15:53:32 -0300
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2017-07-11 11:06:44 -0300
commit94070f86c0c849c71ed2e7e2189bb4d1f7411a17 (patch)
treea7de3d544fc1d3cb5a2b211e0d80b6daf6e93800
parent2a91300176a5991d9825eba085e502196a3f47cd (diff)
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posix: Add p{read,write}v2 RWF_NOWAIT flag (BZ#21738)
Linux 4.12 (b745fafaf70c0a98a2e1e7ac8cb14542889ceb0e) adds a new
p{read,write}v2 flag RWF_NOWAIT.  This patch adds it for linux
uio-ext.h header.

Checked on x86_64-linux-gnu (on a 4.10 kernel).

	[BZ #21738]
	* manual/llio.texi (RWF_NOWAIT): New item.
	* misc/tst-preadvwritev2-common.c (do_test_with_invalid_flags):
	Add RWF_NOWAIT check.
	* sysdeps/unix/sysv/linux/bits/uio-ext.h (RWF_NOWAIT): New flag.
-rw-r--r--ChangeLog8
-rw-r--r--manual/llio.texi4
-rw-r--r--misc/tst-preadvwritev2-common.c15
-rw-r--r--sysdeps/unix/sysv/linux/bits/uio-ext.h1
4 files changed, 18 insertions, 10 deletions
diff --git a/ChangeLog b/ChangeLog
index 71d027ddad..7ee4f2d686 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2017-07-11  Adhemerval Zanella  <adhemerval.zanella@linaro.org>
+
+	[BZ #21738]
+	* manual/llio.texi (RWF_NOWAIT): New item.
+	* misc/tst-preadvwritev2-common.c (do_test_with_invalid_flags):
+	Add RWF_NOWAIT check.
+	* sysdeps/unix/sysv/linux/bits/uio-ext.h (RWF_NOWAIT): New flag.
+
 2017-07-11  Stefan Liebler  <stli@linux.vnet.ibm.com>
 
 	* sysdeps/unix/sysv/linux/s390/tst-ptrace-singleblock.c:
diff --git a/manual/llio.texi b/manual/llio.texi
index ba1f455dfd..e72c53c785 100644
--- a/manual/llio.texi
+++ b/manual/llio.texi
@@ -770,6 +770,10 @@ 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
+Use nonblocking mode for this operation; that is, this call to @code{preadv2}
+will fail and set @code{errno} to @code{EAGAIN} if the operation would block.
 @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 4c53d567b5..8abedc14d0 100644
--- a/misc/tst-preadvwritev2-common.c
+++ b/misc/tst-preadvwritev2-common.c
@@ -16,21 +16,16 @@
    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
+#define RWF_SUPPORTED	(RWF_HIPRI | RWF_DSYNC | RWF_SYNC | RWF_NOWAIT)
+  /* 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 4ddb6448b0..751fc4917d 100644
--- a/sysdeps/unix/sysv/linux/bits/uio-ext.h
+++ b/sysdeps/unix/sysv/linux/bits/uio-ext.h
@@ -46,6 +46,7 @@ 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 nonblocking mode.  */
 
 __END_DECLS