On Sun, 8 Jan 2006, David S. Miller wrote:
From: Davide Libenzi <[email protected]>
Date: Sun, 8 Jan 2006 16:11:10 -0800 (PST)
On Sun, 8 Jan 2006, David S. Miller wrote:
The extra last read is always necessary, it's an error synchronization
barrier. Did you know that?
If a partial read or write hits an error, the successful amount of
bytes read or written before the error occurred is returned. Then any
subsequent read or write will report the error immediately.
Sorry for the missing info, but I was clearly talking about O_NONBLOCK
here.
What I said still applies to O_NONBLOCK.
I thought you said in _not_ necessary, sorry. The extra read() for error
discovery is just bogus, w/out proper Linux poll reporting. The epoll
interface will have wait queue heads dropped inside the monitored devices
wait queue, so I assume that an error condition would trigger a wakeup ->
epoll event. If this is not true (but I'm pretty much sure it is), look at
the extra read() for error reporting:
1) Good
read_loop();
--> Error happen on device
if (read() == ERROR)
gotcha();
2)
read_loop();
if (read() == ERROR)
whoops();
--> Error happen on device
- Davide
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
