Hi Linus,
On Tue, Jun 02, 2020 at 04:55:04PM +0100, David Howells wrote:
> Can you pull this, please? It adds a general notification queue concept
I'm trying to use David's notification stuff in userspace, and I guess
feedback is welcome :-)
The notification stuff looks pretty promising, but I do not understand
why we need to use pipe for this purpose, see typical userspace use-case:
int pipefd[2], fd;
if (pipe2(pipefd, O_NOTIFICATION_PIPE) == -1)
err(EXIT_FAILURE, "pipe2 failed");
fd = pipefd[0];
All the next operations are done with "fd". It's nowhere used as a
pipe, and nothing uses pipefd[1]. The first impression from this code
is "oh, this is strange; why?".
Is it because we need to create a new file descriptor from nothing?
Why O_NOTIFICATION_PIPE is better than introduce a new syscall
notifyfd()?
(We have signalfd(), no O_SIGNAL_PIPE, etc.)
Karel
--
Karel Zak <kzak@xxxxxxxxxx>
http://karelzak.blogspot.com
