Date: Tue, 7 Jul 2009 09:50:04 GMT From: dfilter@FreeBSD.ORG (dfilter service) To: freebsd-bugs@FreeBSD.org Subject: Re: kern/94772: commit references a PR Message-ID: <200907070950.n679o4rt030345@freefall.freebsd.org>
next in thread | raw e-mail | index | archive | help
The following reply was made to PR kern/94772; it has been noted by GNATS. From: dfilter@FreeBSD.ORG (dfilter service) To: bug-followup@FreeBSD.org Cc: Subject: Re: kern/94772: commit references a PR Date: Tue, 7 Jul 2009 09:44:00 +0000 (UTC) Author: kib Date: Tue Jul 7 09:43:44 2009 New Revision: 195423 URL: http://svn.freebsd.org/changeset/base/195423 Log: Fix poll(2) and select(2) for named pipes to return "ready for read" when all writers, observed by reader, exited. Use writer generation counter for fifo, and store the snapshot of the fifo generation in the f_seqcount field of struct file, that is otherwise unused for fifos. Set FreeBSD-undocumented POLLINIGNEOF flag only when file f_seqcount is equal to fifo' fi_wgen, and revert r89376. Fix POLLINIGNEOF for sockets and pipes, and return POLLHUP for them. Note that the patch does not fix not returning POLLHUP for fifos. PR: kern/94772 Submitted by: bde (original version) Reviewed by: rwatson, jilles Approved by: re (kensmith) MFC after: 6 weeks (might be) Modified: head/sys/fs/fifofs/fifo_vnops.c head/sys/kern/sys_pipe.c head/sys/kern/uipc_socket.c head/sys/sys/socketvar.h Modified: head/sys/fs/fifofs/fifo_vnops.c ============================================================================== --- head/sys/fs/fifofs/fifo_vnops.c Tue Jul 7 00:02:26 2009 (r195422) +++ head/sys/fs/fifofs/fifo_vnops.c Tue Jul 7 09:43:44 2009 (r195423) @@ -84,6 +84,7 @@ struct fifoinfo { struct socket *fi_writesock; long fi_readers; long fi_writers; + int fi_wgen; }; static vop_print_t fifo_print; @@ -232,6 +233,7 @@ fail1: sowwakeup(fip->fi_writesock); } } + fp->f_seqcount = fip->fi_wgen - fip->fi_writers; } if (ap->a_mode & FWRITE) { if ((ap->a_mode & O_NONBLOCK) && fip->fi_readers == 0) { @@ -279,6 +281,9 @@ fail1: fip->fi_writers--; if (fip->fi_writers == 0) { socantrcvmore(fip->fi_readsock); + mtx_lock(&fifo_mtx); + fip->fi_wgen++; + mtx_unlock(&fifo_mtx); fifo_cleanup(vp); } return (error); @@ -395,8 +400,12 @@ fifo_close(ap) } if (ap->a_fflag & FWRITE) { fip->fi_writers--; - if (fip->fi_writers == 0) + if (fip->fi_writers == 0) { socantrcvmore(fip->fi_readsock); + mtx_lock(&fifo_mtx); + fip->fi_wgen++; + mtx_unlock(&fifo_mtx); + } } fifo_cleanup(vp); return (0); @@ -634,28 +643,13 @@ fifo_poll_f(struct file *fp, int events, levents = events & (POLLIN | POLLINIGNEOF | POLLPRI | POLLRDNORM | POLLRDBAND); if ((fp->f_flag & FREAD) && levents) { - /* - * If POLLIN or POLLRDNORM is requested and POLLINIGNEOF is - * not, then convert the first two to the last one. This - * tells the socket poll function to ignore EOF so that we - * block if there is no writer (and no data). Callers can - * set POLLINIGNEOF to get non-blocking behavior. - */ - if (levents & (POLLIN | POLLRDNORM) && - !(levents & POLLINIGNEOF)) { - levents &= ~(POLLIN | POLLRDNORM); - levents |= POLLINIGNEOF; - } - filetmp.f_data = fip->fi_readsock; filetmp.f_cred = cred; + mtx_lock(&fifo_mtx); + if (fp->f_seqcount == fip->fi_wgen) + levents |= POLLINIGNEOF; + mtx_unlock(&fifo_mtx); revents |= soo_poll(&filetmp, levents, cred, td); - - /* Reverse the above conversion. */ - if ((revents & POLLINIGNEOF) && !(events & POLLINIGNEOF)) { - revents |= (events & (POLLIN | POLLRDNORM)); - revents &= ~POLLINIGNEOF; - } } levents = events & (POLLOUT | POLLWRNORM | POLLWRBAND); if ((fp->f_flag & FWRITE) && levents) { Modified: head/sys/kern/sys_pipe.c ============================================================================== --- head/sys/kern/sys_pipe.c Tue Jul 7 00:02:26 2009 (r195422) +++ head/sys/kern/sys_pipe.c Tue Jul 7 09:43:44 2009 (r195423) @@ -1353,8 +1353,7 @@ pipe_poll(fp, events, active_cred, td) #endif if (events & (POLLIN | POLLRDNORM)) if ((rpipe->pipe_state & PIPE_DIRECTW) || - (rpipe->pipe_buffer.cnt > 0) || - (rpipe->pipe_state & PIPE_EOF)) + (rpipe->pipe_buffer.cnt > 0)) revents |= events & (POLLIN | POLLRDNORM); if (events & (POLLOUT | POLLWRNORM)) @@ -1364,10 +1363,14 @@ pipe_poll(fp, events, active_cred, td) (wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) >= PIPE_BUF)) revents |= events & (POLLOUT | POLLWRNORM); - if ((rpipe->pipe_state & PIPE_EOF) || - wpipe->pipe_present != PIPE_ACTIVE || - (wpipe->pipe_state & PIPE_EOF)) - revents |= POLLHUP; + if ((events & POLLINIGNEOF) == 0) { + if (rpipe->pipe_state & PIPE_EOF) { + revents |= (events & (POLLIN | POLLRDNORM)); + if (wpipe->pipe_present != PIPE_ACTIVE || + (wpipe->pipe_state & PIPE_EOF)) + revents |= POLLHUP; + } + } if (revents == 0) { if (events & (POLLIN | POLLRDNORM)) { Modified: head/sys/kern/uipc_socket.c ============================================================================== --- head/sys/kern/uipc_socket.c Tue Jul 7 00:02:26 2009 (r195422) +++ head/sys/kern/uipc_socket.c Tue Jul 7 09:43:44 2009 (r195423) @@ -2885,14 +2885,9 @@ sopoll_generic(struct socket *so, int ev SOCKBUF_LOCK(&so->so_snd); SOCKBUF_LOCK(&so->so_rcv); if (events & (POLLIN | POLLRDNORM)) - if (soreadable(so)) + if (soreadabledata(so)) revents |= events & (POLLIN | POLLRDNORM); - if (events & POLLINIGNEOF) - if (so->so_rcv.sb_cc >= so->so_rcv.sb_lowat || - !TAILQ_EMPTY(&so->so_comp) || so->so_error) - revents |= POLLINIGNEOF; - if (events & (POLLOUT | POLLWRNORM)) if (sowriteable(so)) revents |= events & (POLLOUT | POLLWRNORM); @@ -2901,10 +2896,16 @@ sopoll_generic(struct socket *so, int ev if (so->so_oobmark || (so->so_rcv.sb_state & SBS_RCVATMARK)) revents |= events & (POLLPRI | POLLRDBAND); + if ((events & POLLINIGNEOF) == 0) { + if (so->so_rcv.sb_state & SBS_CANTRCVMORE) { + revents |= events & (POLLIN | POLLRDNORM); + if (so->so_snd.sb_state & SBS_CANTSENDMORE) + revents |= POLLHUP; + } + } + if (revents == 0) { - if (events & - (POLLIN | POLLINIGNEOF | POLLPRI | POLLRDNORM | - POLLRDBAND)) { + if (events & (POLLIN | POLLPRI | POLLRDNORM | POLLRDBAND)) { selrecord(td, &so->so_rcv.sb_sel); so->so_rcv.sb_flags |= SB_SEL; } Modified: head/sys/sys/socketvar.h ============================================================================== --- head/sys/sys/socketvar.h Tue Jul 7 00:02:26 2009 (r195422) +++ head/sys/sys/socketvar.h Tue Jul 7 09:43:44 2009 (r195423) @@ -197,10 +197,11 @@ struct xsocket { ((so)->so_proto->pr_flags & PR_ATOMIC) /* can we read something from so? */ -#define soreadable(so) \ +#define soreadabledata(so) \ ((so)->so_rcv.sb_cc >= (so)->so_rcv.sb_lowat || \ - ((so)->so_rcv.sb_state & SBS_CANTRCVMORE) || \ !TAILQ_EMPTY(&(so)->so_comp) || (so)->so_error) +#define soreadable(so) \ + (soreadabledata(so) || ((so)->so_rcv.sb_state & SBS_CANTRCVMORE)) /* can we write something to so? */ #define sowriteable(so) \ _______________________________________________ svn-src-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscribe@freebsd.org"
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200907070950.n679o4rt030345>