Re: [PATCH] i3c: master: svc: fix signed/unsigned mismatch in dynamic address assignment

[Frank Li]

On Tue, Mar 18, 2025 at 02:41:47PM +0000, Qasim Ijaz wrote:
> On Tue, Mar 18, 2025 at 09:40:17AM -0400, Frank Li wrote:
> > On Mon, Mar 17, 2025 at 10:15:16AM +0000, Qasim Ijaz wrote:
> > > svc_i3c_master_do_daa_locked() declares dyn_addr as an unsigned int
> > > however it initialises it with i3c_master_get_free_addr() which
> > > returns a signed int type and then attempts to check if dyn_addr is
> > > less than 0. Unsigned integers cannot be less than 0, so the check
> > > is essentially redundant. Furthermore i3c_master_get_free_addr()
> > > could return -ENOMEM which an unsigned int cannot store.
> > >
> > > Fix this by capturing the return value of i3c_master_get_free_addr()
> > > in a signed int ‘dyn_addr_ret’. If that value is negative, return
> > > an error. Otherwise, assign it to the unsigned int ‘dyn_addr’ once
> > > we know it’s valid.
> > >
> > > Fixes: 4008a74e0f9b ("i3c: master: svc: Fix npcm845 FIFO empty issue")
> > > Signed-off-by: Qasim Ijaz <qasdev00@xxxxxxxxx>
> > > ---
> >
> > Thank you for your patch, but similar one was already applied
> > https://lore.kernel.org/linux-i3c/174225158210.1593610.10018812780731849409.b4-ty@xxxxxxxxxxx/T/#m5120e1c362e7e57f4cab139a45410fde421c2f37
> >
>
> Hi Frank
>
> I sent a fix for this issue on the 9th March, which is before the patch
> you linked which was sent on the 10th March.

Yes, but perfer original owner to fix this type minor fix.

https://lore.kernel.org/linux-i3c/174129444617.1163689.11942276093411687387.b4-ty@xxxxxxxxxxx/T/#t

Frank
>
> You can view my orignal patch here:
>
> https://lore.kernel.org/all/20250309164314.15039-1-qasdev00@xxxxxxxxx/
>
> Thanks
> Qasim
> > Frank
> > >  drivers/i3c/master/svc-i3c-master.c | 5 +++--
> > >  1 file changed, 3 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
> > > index f22fb9e75142..eea08f00d7ce 100644
> > > --- a/drivers/i3c/master/svc-i3c-master.c
> > > +++ b/drivers/i3c/master/svc-i3c-master.c
> > > @@ -998,9 +998,10 @@ static int svc_i3c_master_do_daa_locked(struct svc_i3c_master *master,
> > >  			 * filling within a few hundred nanoseconds, which is significantly
> > >  			 * faster compared to the 64 SCL clock cycles.
> > >  			 */
> > > -			dyn_addr = i3c_master_get_free_addr(&master->base, last_addr + 1);
> > > -			if (dyn_addr < 0)
> > > +			int dyn_addr_ret = i3c_master_get_free_addr(&master->base, last_addr + 1);
> > > +			if (dyn_addr_ret < 0)
> > >  				return -ENOSPC;
> > > +			dyn_addr = dyn_addr_ret;
> > >
> > >  			writel(dyn_addr, master->regs + SVC_I3C_MWDATAB);
> > >
> > > --
> > > 2.39.5
> > >
>
> --
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