Re: [PATCH] gpiolib: Fix incorrect use of find_next_zero_bit()

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Sat, Sep 29, 2018 at 2:19 PM Janusz Krzysztofik <jmkrzyszt@xxxxxxxxx> wrote:

> Commit b17566a6b08b ("gpiolib: Implement fast processing path in
> get/set array"), already fixed to some extent with commit 5d581d7e8cdc
> ("gpiolib: Fix missing updates of bitmap index"), introduced a new mode
> of processing bitmaps where bits applicable for fast bitmap processing
> path are supposed to be skipped while iterating bits which don't apply.
> Unfortunately, find_next_zero_bit() function supposed to skip over
> those fast bits is always called with a 'start' argument equal to an
> index of last zero bit found and returns that index value again an
> again, causing an infinite loop.
>
> Fix it by incrementing the index uncoditionally before
> find_next_zero_bit() is optionally called.
>
> Reported-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> Signed-off-by: Janusz Krzysztofik <jmkrzyszt@xxxxxxxxx>

Patch applied with Marek's Tested-by.

Thanks to both of you for digging in and fixing this up!
Now we are in good shape for the v4.20 cycle :)

Yours,
Linus Walleij