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USB: O_NONBLOCK in read path of skeleton

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Non blocking IO is supported in the read path of usb-skeleton.
This is done by just not blocking. As support for handling signals
without stopping IO is already there, it can be used for O_NONBLOCK, too.

Signed-off-by: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Oliver Neukum
2009-09-09 17:08:50 +02:00
committed by Greg Kroah-Hartman
parent 7981998673
commit 8cd0166434
1 changed files with 7 additions and 1 deletions
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8
drivers/usb/usb-skeleton.c
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@@ -268,6 +268,11 @@ retry:
spin_unlock_irq(&dev->err_lock); spin_unlock_irq(&dev->err_lock);
if (ongoing_io) { if (ongoing_io) {
/* nonblocking IO shall not wait */
if (file->f_flags & O_NONBLOCK) {
rv = -EAGAIN;
goto exit;
}
/* /*
* IO may take forever * IO may take forever
* hence wait in an interruptible state * hence wait in an interruptible state
@@ -351,8 +356,9 @@ retry:
rv = skel_do_read_io(dev, count); rv = skel_do_read_io(dev, count);
if (rv < 0) if (rv < 0)
goto exit; goto exit;
else else if (!file->f_flags & O_NONBLOCK)
goto retry; goto retry;
rv = -EAGAIN;
} }
exit: exit:
mutex_unlock(&dev->io_mutex); mutex_unlock(&dev->io_mutex);