posix: Add p{read,write}v2 RWF_NOWAIT flag (BZ#21738)
Commit Message
On 10/07/2017 16:36, Zack Weinberg wrote:
> Argh, one more thing:
>
> On Mon, Jul 10, 2017 at 3:34 PM, Zack Weinberg <zackw@panix.com> wrote:
>>
>> Suggest instead "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."
>
> "... this call to @code{preadv2} or @code{pwritev2} ..." It does work
> in both, right?
>
> zw
>
That's the new version:
[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.
---
Comments
On 2017.07.10 at 16:47 -0300, Adhemerval Zanella wrote:
>
>
> On 10/07/2017 16:36, Zack Weinberg wrote:
> > Argh, one more thing:
> >
> > On Mon, Jul 10, 2017 at 3:34 PM, Zack Weinberg <zackw@panix.com> wrote:
> >>
> >> Suggest instead "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."
> >
> > "... this call to @code{preadv2} or @code{pwritev2} ..." It does work
> > in both, right?
> >
> > zw
> >
>
> That's the new version:
>
> * sysdeps/unix/sysv/linux/bits/uio-ext.h (RWF_NOWAIT): New flag.
> 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)
In case you haven't noticed already, this still defines RWF_SUPPORTED in
uio-ext.h.
On 11/07/2017 08:06, Markus Trippelsdorf wrote:
> On 2017.07.10 at 16:47 -0300, Adhemerval Zanella wrote:
>>
>>
>> On 10/07/2017 16:36, Zack Weinberg wrote:
>>> Argh, one more thing:
>>>
>>> On Mon, Jul 10, 2017 at 3:34 PM, Zack Weinberg <zackw@panix.com> wrote:
>>>>
>>>> Suggest instead "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."
>>>
>>> "... this call to @code{preadv2} or @code{pwritev2} ..." It does work
>>> in both, right?
>>>
>>> zw
>>>
>>
>> That's the new version:
>>
>> * sysdeps/unix/sysv/linux/bits/uio-ext.h (RWF_NOWAIT): New flag.
>
>> 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)
>
> In case you haven't noticed already, this still defines RWF_SUPPORTED in
> uio-ext.h.
>
Ugh, I will fix it, thanks for spotting it.
@@ -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
@@ -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) };
@@ -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