On Thu, Jul 10, 2014 at 07:08:07PM +0300, Konstantin Belousov wrote: > On Thu, Jul 10, 2014 at 03:52:53PM +0200, Baptiste Daroussin wrote: > > On Thu, Jul 10, 2014 at 04:28:13PM +0300, Konstantin Belousov wrote: > > > On Thu, Jul 10, 2014 at 01:04:53PM +0000, Baptiste Daroussin wrote: > > > > Author: bapt > > > > Date: Thu Jul 10 13:04:52 2014 > > > > New Revision: 268493 > > > > URL: http://svnweb.freebsd.org/changeset/base/268493 > > > > > > > > Log: > > > > Support EAGAIN in fetch_writev > > > > > > > > Reviewed by: des > > > > Approved by: des > > > > > > > > Modified: > > > > head/lib/libfetch/common.c > > > > > > > > Modified: head/lib/libfetch/common.c > > > > ============================================================================== > > > > --- head/lib/libfetch/common.c Thu Jul 10 12:41:58 2014 > > > > (r268492) > > > > +++ head/lib/libfetch/common.c Thu Jul 10 13:04:52 2014 > > > > (r268493) > > > > @@ -1110,6 +1110,8 @@ fetch_writev(conn_t *conn, struct iovec > > > > errno = 0; > > > > pfd.revents = 0; > > > > if (poll(&pfd, 1, deltams) < 0) { > > > > + if (errno == EAGAIN) > > > > + continue; > > > > if (errno == EINTR && fetchRestartCalls) > > > > continue; > > > > return (-1); > > > > > > How is this error possible ? poll(2) converts EAGAIN from seltdwait(9) > > > to no error. > > > > For posix compliance, libfetch is not only used on FreeBSD, reading at: > > http://pubs.opengroup.org/onlinepubs/009695399/functions/poll.html I can > > read: > > > > [EAGAIN] > > The allocation of internal data structures failed but a subsequent > > request > > may succeed. > > > > Am I missing something? > > At least for me, it was very surprising. I accustomed to the facts that > poll(2) is never restarted after signal, and that you only should test > for EINTR as the error condition. > > Apparently, the behaviour of converting EAGAIN to no error can be tracked > back to at least 4.4 lite. On the other hand, just looking into the man > page for poll(2) on STREAMS-based systems indeed mention EAGAIN. > > My suggestion is to add a comment, noting that FreeBSD does not return > EAGAIN from poll(2), but SUSv4 allows it. This way, the addition would > be not removed in some code cleanup. Does it sound reasonable ?
More that reasonable (I was thinking something like this as well) I will do it tomorrow. regards, Bapt
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