On Wed, 7 Jul 2004, Andrew Morton wrote:
> Greg KH <[EMAIL PROTECTED]> wrote:
> >
> > On Sat, Jul 03, 2004 at 12:23:30AM -0700, [EMAIL PROTECTED] wrote:
> > >
> > >
> > > usb_trylock_device() returns non-zero on success.
> > >
> > > Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
> >
> > Applied, thanks.
> >
>
> Can you unapply it and apply this one instead?
>
>
> From: Alan Stern <[EMAIL PROTECTED]>
>
> As Andrew Morton has already spotted, I messed up the interpretation of the
> result codes from various _trylock() routines. I didn't notice that
> down_trylock() and down_read_trylock() use opposite conventions for
> indicating success! This patch fixes the incorrect interpretation of
> down_trylock(). That error may well be responsible for some of the
> problems cropping up recently with OHCI controllers.
>
> Signed-off-by: Alan Stern <[EMAIL PROTECTED]>
> Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
> ---
>
> 25-akpm/drivers/usb/core/usb.c | 2 +-
> 1 files changed, 1 insertion(+), 1 deletion(-)
>
> diff -puN
> drivers/usb/core/usb.c~as339-interpret-down_trylock-result-code-correctly-in
> drivers/usb/core/usb.c
> --- 25/drivers/usb/core/usb.c~as339-interpret-down_trylock-result-code-correctly-in
> Tue Jul 6 17:10:05 2004
> +++ 25-akpm/drivers/usb/core/usb.c Tue Jul 6 17:10:05 2004
> @@ -871,7 +871,7 @@ int usb_trylock_device(struct usb_device
> {
> if (!down_read_trylock(&usb_all_devices_rwsem))
> return 0;
> - if (!down_trylock(&udev->serialize)) {
> + if (down_trylock(&udev->serialize)) {
> up_read(&usb_all_devices_rwsem);
> return 0;
> }
> _
No, no -- don't unapply it! Andrew's change was correct. _Both_ patches
need to be applied.
The basic problem is that usb_trylock_device(), like down_read_trylock(),
returns 1 for success whereas down_trylock() returns 0 for success. My
first patch, as329, replaced one occurrence of down_trylock in ohci-hub.c
with usb_trylock_device() but failed to invert the test of the return code
-- that's what Andrew's patch fixed. In as329 there was one other
occurrence of down_trylock(), and again I misinterpreted the return code
-- that's what the patch above (as339) fixes.
Alan Stern
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