Re: [PATCH v8 06/11] dma-buf: provide phys_vec to scatter-gather mapping routine

Leon Romanovsky
2025-11-19T13:45:32Z

On Wed, Nov 19, 2025 at 09:37:08AM -0400, Jason Gunthorpe wrote:
> On Wed, Nov 19, 2025 at 03:30:00PM +0200, Leon Romanovsky wrote:
> > On Wed, Nov 19, 2025 at 05:54:55AM +0000, Tian, Kevin wrote:
> > > > From: Leon Romanovsky <leon@kernel.org>
> > > > Sent: Tuesday, November 11, 2025 5:58 PM
> > > > +
> > > > + if (dma->state && dma_use_iova(dma->state)) {
> > > > + WARN_ON_ONCE(mapped_len != size);
> > >
> > > then "goto err_unmap_dma".
> >
> > It never should happen, there is no need to provide error unwind to
> > something that you won't get.
>
> It is expected that WARN_ON has recovery code, if it is possible and
> not burdensome.

It’s not necessary, but since I’m calculating mapped_len again, it’s natural—and completely
harmless—to double-check the arithmetic.

Thanks

>
> Jason