Hi Kees and Andrew,

On Thu, Apr 16, 2026 at 10:48:51AM +0300, Andy Shevchenko wrote:
> On Wed, Apr 15, 2026 at 05:30:50PM +0200, Thorsten Blum wrote:
> > On Wed, Apr 15, 2026 at 05:42:41PM +0300, Andy Shevchenko wrote:
> > > On Wed, Apr 15, 2026 at 02:25:43PM +0200, Thorsten Blum wrote:
> > > > kasprintf_strarray() returns an array of N strings and kfree_strarray()
> > > > also frees N entries.  However, kasprintf_strarray() currently allocates
> > > > N+1 char pointers.  Allocate exactly N pointers instead of N+1.
> > > > 
> > > > Also update the kernel-doc for @n.
> > > 
> > > Have you checked all current users that they do not rely on the NULL 
> > > terminated
> > > array?
> > 
> > Yes, I've checked all call sites, and none of them rely on the NULL
> > terminator. Specifically, I checked:
> > 
> >   drivers/gpio/gpio-mockup.c
> > 
> > which uses PROPERTY_ENTRY_STRING_ARRAY_LEN(), and
> > 
> >   drivers/pinctrl/bcm/pinctrl-bcm4908.c
> >   drivers/pinctrl/intel/pinctrl-intel-platform.c
> >   drivers/pinctrl/meson/pinctrl-amlogic-a4.c
> >   drivers/pinctrl/mvebu/pinctrl-armada-37xx.c
> >   drivers/pinctrl/pinctrl-at91.c
> >   drivers/pinctrl/pinctrl-rockchip.c
> >   drivers/pinctrl/pinctrl-st.c
> > 
> > all of which use the size N to iterate over the returned array.
> 
> Thanks for confirming.
> 
> > Also, kfree_strarray() explicitly takes the number of entries N,
> > indicating that callers are expected to keep track of it.
> 
> Still we might have an API that requires a NULL terminated arrays (when it
> doesn't take size), which a caller wants to use.
> 
> > > Note, that was done on purpose that once allocated it can allow user
> > > to drop the track of the number of strings and rely on NULL terminator.
> > > I.o.w.  the number of strings may be just a local variable somewhere
> > > where kasprintf_strarray() is called.
> > > 
> > > I tend to NAK this change, rather you can update kernel-doc to explain
> > > why it's done this way (see above).
> 
> Given pros and cons, and what David said I'm still not sure that this is
> going to be a beneficial patch. I leave it Kees and Andrew to decide.

What's your take on this and the __counted_by_ptr() annotation from
patch 2/2?

Thanks,
Thorsten

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