From: Al Viro <viro@ZenIV.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
David Miller <davem@davemloft.net>,
Stephen Hemminger <stephen@networkplumber.org>,
Network Development <netdev@vger.kernel.org>,
David Howells <dhowells@redhat.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [Bug 106241] New: shutdown(3)/close(3) behaviour is incorrect for sockets in accept(3)
Date: Sat, 31 Oct 2015 21:51:16 +0000 [thread overview]
Message-ID: <20151031215116.GO22011@ZenIV.linux.org.uk> (raw)
In-Reply-To: <CA+55aFz9wm7LssaaUzmo-NYNGW88gb_TkUFSJoFJrY+fvtt8+A@mail.gmail.com>
On Sat, Oct 31, 2015 at 02:23:31PM -0700, Linus Torvalds wrote:
> The other stuff we probably can't do all that much about. Unless we
> decide to go for some complicated lockless optimistic file descriptor
> allocation scheme with retry-on-failure instead of locks. Which I'm
> sure is possible, but I'm equally sure is painful.
The interesting part is dup2() - we'd have to do something like
serialize against other dup2
was_claimed = atomically set and test bit in bitmap
if was_claimed
tofree = fdt->fd[fd];
if (!tofree)
fail with EBUSY
install into ->fd[...]
end of critical area
in there; __alloc_fd() could be made retry-on-failure, but I don't see
how to cope with dup2 vs. dup2 without an explicit exclusion.
next prev parent reply other threads:[~2015-10-31 21:51 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <201510221824.t9MIOp6n003978@room101.nl.oracle.com>
[not found] ` <20151022190701.GV22011@ZenIV.linux.org.uk>
[not found] ` <201510221951.t9MJp5LC005892@room101.nl.oracle.com>
[not found] ` <20151022215741.GW22011@ZenIV.linux.org.uk>
[not found] ` <201510230952.t9N9qYZJ021998@room101.nl.oracle.com>
[not found] ` <20151024023054.GZ22011@ZenIV.linux.org.uk>
[not found] ` <201510270908.t9R9873a001683@room101.nl.oracle.com>
[not found] ` <562F577E.6000901@oracle.com>
[not found] ` <20151027231702.GA22011@ZenIV.linux.org.uk>
[not found] ` <1445991236.7476.59.camel@edumazet-glaptop2.roam.corp.google.com>
2015-10-28 12:35 ` [Bug 106241] New: shutdown(3)/close(3) behaviour is incorrect for sockets in accept(3) Al Viro
2015-10-28 13:24 ` Eric Dumazet
2015-10-28 14:47 ` Eric Dumazet
2015-10-28 21:13 ` Al Viro
2015-10-28 21:44 ` Eric Dumazet
2015-10-28 22:33 ` Al Viro
2015-10-28 23:08 ` Eric Dumazet
2015-10-29 0:15 ` Al Viro
2015-10-29 3:29 ` Eric Dumazet
2015-10-29 4:16 ` Al Viro
2015-10-29 12:35 ` Eric Dumazet
2015-10-29 13:48 ` Eric Dumazet
2015-10-30 17:18 ` Linus Torvalds
2015-10-30 21:02 ` Al Viro
2015-10-30 21:23 ` Linus Torvalds
2015-10-30 21:50 ` Linus Torvalds
2015-10-30 22:33 ` Al Viro
2015-10-30 23:52 ` Linus Torvalds
2015-10-31 0:09 ` Al Viro
2015-10-31 15:59 ` Eric Dumazet
2015-10-31 19:34 ` Al Viro
2015-10-31 19:54 ` Linus Torvalds
2015-10-31 20:29 ` Al Viro
2015-11-02 0:24 ` Al Viro
2015-11-02 0:59 ` Linus Torvalds
2015-11-02 2:14 ` Eric Dumazet
2015-11-02 6:22 ` Al Viro
2015-10-31 20:45 ` Eric Dumazet
2015-10-31 21:23 ` Linus Torvalds
2015-10-31 21:51 ` Al Viro [this message]
2015-10-31 22:34 ` Eric Dumazet
2015-10-31 1:07 ` Eric Dumazet
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