kern/156567: commit references a PR

[dfilter service]

The following reply was made to PR kern/156567; it has been noted by GNATS.

From: dfilter at FreeBSD.ORG (dfilter service)
To: bug-followup at FreeBSD.org
Cc:  
Subject: Re: kern/156567: commit references a PR
Date: Wed,  1 Feb 2012 02:53:15 +0000 (UTC)

 Author: davidxu
 Date: Wed Feb  1 02:53:06 2012
 New Revision: 230857
 URL: http://svn.freebsd.org/changeset/base/230857
 
 Log:
   If multiple threads call kevent() to get AIO events on same kqueue fd,
   it is possible that a single AIO event will be reported to multiple
   threads, it is not threading friendly, and the existing API can not
   control this behavior.
   Allocate a kevent flags field sigev_notify_kevent_flags for AIO event
   notification in sigevent, and allow user to pass EV_CLEAR, EV_DISPATCH
   or EV_ONESHOT to AIO kernel code, user can control whether the event
   should be cleared once it is retrieved by a thread. This change should
   be comptaible with existing application, because the field should have
   already been zero-filled, and no additional action will be taken by
   kernel.
   
   PR:	kern/156567
 
 Modified:
   head/sys/kern/vfs_aio.c
   head/sys/sys/signal.h
 
 Modified: head/sys/kern/vfs_aio.c
 ==============================================================================
 --- head/sys/kern/vfs_aio.c	Wed Feb  1 02:16:15 2012	(r230856)
 +++ head/sys/kern/vfs_aio.c	Wed Feb  1 02:53:06 2012	(r230857)
 @@ -1524,6 +1524,7 @@ aio_aqueue(struct thread *td, struct aio
  	int error;
  	int fd, kqfd;
  	int jid;
 +	u_short evflags;
  
  	if (p->p_aioinfo == NULL)
  		aio_init_aioinfo(p);
 @@ -1646,10 +1647,15 @@ aio_aqueue(struct thread *td, struct aio
  
  	if (aiocbe->uaiocb.aio_sigevent.sigev_notify != SIGEV_KEVENT)
  		goto no_kqueue;
 +	evflags = aiocbe->uaiocb.aio_sigevent.sigev_notify_kevent_flags;
 +	if ((evflags & ~(EV_CLEAR | EV_DISPATCH | EV_ONESHOT)) != 0) {
 +		error = EINVAL;
 +		goto aqueue_fail;
 +	}
  	kqfd = aiocbe->uaiocb.aio_sigevent.sigev_notify_kqueue;
  	kev.ident = (uintptr_t)aiocbe->uuaiocb;
  	kev.filter = EVFILT_AIO;
 -	kev.flags = EV_ADD | EV_ENABLE | EV_FLAG1;
 +	kev.flags = EV_ADD | EV_ENABLE | EV_FLAG1 | evflags;
  	kev.data = (intptr_t)aiocbe;
  	kev.udata = aiocbe->uaiocb.aio_sigevent.sigev_value.sival_ptr;
  	error = kqfd_register(kqfd, &kev, td, 1);
 
 Modified: head/sys/sys/signal.h
 ==============================================================================
 --- head/sys/sys/signal.h	Wed Feb  1 02:16:15 2012	(r230856)
 +++ head/sys/sys/signal.h	Wed Feb  1 02:53:06 2012	(r230857)
 @@ -169,12 +169,14 @@ struct sigevent {
  			void (*_function)(union sigval);
  			void *_attribute; /* pthread_attr_t * */
  		} _sigev_thread;
 +		unsigned short _kevent_flags;
  		long __spare__[8];
  	} _sigev_un;
  };
  
  #if __BSD_VISIBLE
  #define	sigev_notify_kqueue		sigev_signo
 +#define	sigev_notify_kevent_flags	_sigev_un._kevent_flags
  #define	sigev_notify_thread_id		_sigev_un._threadid
  #endif
  #define	sigev_notify_function		_sigev_un._sigev_thread._function
 _______________________________________________
 svn-src-all at freebsd.org mailing list
 http://lists.freebsd.org/mailman/listinfo/svn-src-all
 To unsubscribe, send any mail to "svn-src-all-unsubscribe at freebsd.org"