Messages in this thread | | | From | Bartosz Golaszewski <> | Date | Wed, 29 Apr 2020 08:40:03 +0200 | Subject | Re: [PATCH] gpiolib: don't call sleeping functions with a spinlock taken |
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wt., 28 kwi 2020 o 17:53 Andy Shevchenko <andy.shevchenko@gmail.com> napisał(a): > > On Tue, Apr 14, 2020 at 6:35 PM Bartosz Golaszewski > <bgolaszewski@baylibre.com> wrote: > > > > wt., 14 kwi 2020 o 14:00 Linus Walleij <linus.walleij@linaro.org> napisał(a): > > > > > > On Fri, Mar 20, 2020 at 10:31 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote: > > > > > > > From: Bartosz Golaszewski <bgolaszewski@baylibre.com> > > > > > > > > We must not call pinctrl_gpio_can_use_line() with the gpio_lock taken > > > > as it takes a mutex internally. Let's move the call before taking the > > > > spinlock and store the return value. > > > > > > > > This isn't perfect - there's a moment between calling > > > > pinctrl_gpio_can_use_line() and taking the spinlock where the situation > > > > can change but it isn't a regression either: previously this part wasn't > > > > protected at all and it only affects the information user-space is > > > > seeing. > > It seems I have no original at hand, so, commenting here. > > It looks like we need a mutex less function which can be used here and > in the call you are considering racy.
The thing is this mutex is in pinctrl - we'd need to export it too so that gpio can use it.
Bart
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