Re: Patch 2/5

On 2010-10-28, Lino Sanfilippo <[email protected]> wrote:
>>> This patch enables behaviour compatible with BSD signal semantics
>>> by making the read() calls on the dazukofs devices restartable
>>> across signals.
>
a> Userspace will (in most cases) still see -EINTR if interrupted by a
> signal (in fact -ERESTARTSYS should never be seen by userspace).
> The exception is if a signal handler has been installed with the
> SA_RESTART flag set, the kernel will try to restart the interrupted
> system call (read() from dazukofs device in our case) and not notify
> userspace.  This is a feature that has been introduced by BSD and is
> also supported by Linux.  I thought it would be nice if dazukofs
> would support those semantics, too (i know some device drivers do,
> but I dont think its something a device _has_ to support...)

Thank you for the explanation. I wasn't sure because I couldn't find
the Linux code that shows how this was being handled. (But I must
admit that I did not look very hard.) I will include the patch for the
next release candidate.

John Ogness