svn commit: r190997 - in stable/7/sys: . contrib/pf dev/ath/ath_hal dev/cxgb kern

[Robert Watson]

On Mon, 13 Apr 2009, Robert Watson wrote:

> Author: rwatson
> Date: Mon Apr 13 11:54:22 2009
> New Revision: 190997
> URL: http://svn.freebsd.org/changeset/base/190997
>
> Log:
>  Merge r190996 from head to stable/7:

Due to a clerical error, this is not the right revision number.  The actual 
merged revision is r189708.

Robert N M Watson
Computer Laboratory
University of Cambridge

>
>    When writing out updated pollfd records when returning from
>    poll(), only copy out the revents field, not the whole pollfd
>    structure.  Otherwise, if the events field is updated
>    concurrently by another thread, that update may be lost.
>
>    This issue apparently causes problems for the JDK on FreeBSD,
>    which expects the Linux behavior of not updating all fields
>    (somewhat oddly, Solaris does not implement the required
>    behavior, but presumably our adaptation of the JDK is based
>    on the Linux port?).
>
>    MFC after:      2 weeks
>    PR:             kern/130924
>    Submitted by:   Kurt Miller <kurt @ intricatesoftware.com>
>    Discussed with: kib
>
>  Approved by:	re (kib)
>
> Modified:
>  stable/7/sys/   (props changed)
>  stable/7/sys/contrib/pf/   (props changed)
>  stable/7/sys/dev/ath/ath_hal/   (props changed)
>  stable/7/sys/dev/cxgb/   (props changed)
>  stable/7/sys/kern/sys_generic.c
>
> Modified: stable/7/sys/kern/sys_generic.c
> ==============================================================================
> --- stable/7/sys/kern/sys_generic.c	Mon Apr 13 10:41:41 2009	(r190996)
> +++ stable/7/sys/kern/sys_generic.c	Mon Apr 13 11:54:22 2009	(r190997)
> @@ -73,6 +73,7 @@ static MALLOC_DEFINE(M_IOCTLOPS, "ioctlo
> static MALLOC_DEFINE(M_SELECT, "select", "select() buffer");
> MALLOC_DEFINE(M_IOV, "iov", "large iov's");
>
> +static int	pollout(struct pollfd *, struct pollfd *, u_int);
> static int	pollscan(struct thread *, struct pollfd *, u_int);
> static int	selscan(struct thread *, fd_mask **, fd_mask **, int);
> static int	dofileread(struct thread *, int, struct file *, struct uio *,
> @@ -992,7 +993,7 @@ done_nosellock:
> 	if (error == EWOULDBLOCK)
> 		error = 0;
> 	if (error == 0) {
> -		error = copyout(bits, uap->fds, ni);
> +		error = pollout(bits, uap->fds, nfds);
> 		if (error)
> 			goto out;
> 	}
> @@ -1004,6 +1005,26 @@ done2:
> }
>
> static int
> +pollout(fds, ufds, nfd)
> +	struct pollfd *fds;
> +	struct pollfd *ufds;
> +	u_int nfd;
> +{
> +	int error = 0;
> +	u_int i = 0;
> +
> +	for (i = 0; i < nfd; i++) {
> +		error = copyout(&fds->revents, &ufds->revents,
> +		    sizeof(ufds->revents));
> +		if (error)
> +			return (error);
> +		fds++;
> +		ufds++;
> +	}
> +	return (0);
> +}
> +
> +static int
> pollscan(td, fds, nfd)
> 	struct thread *td;
> 	struct pollfd *fds;
>