Re: [PATCH next] mtd: rawnand: loongson1: Fix error code in ls1x_nand_dma_transfer()

[Dan Carpenter <dan.carpenter@linaro.org>]

On Tue, May 06, 2025 at 05:16:03PM +0800, Keguang Zhang wrote:
> On Fri, May 2, 2025 at 4:39 PM Dan Carpenter <dan.carpenter@linaro.org> wrote:
> >
> > The "desc" variable is NULL and PTR_ERR(NULL) is zero/success.  Return
> > a negative error code instead.
> >
> > Fixes: d2d10ede04b1 ("mtd: rawnand: Add Loongson-1 NAND Controller Driver")
> > Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
> > ---
> > It's hard to know what the patch prefix should be here.  Ideally when we
> > add a new driver we would use the patch prefix for the driver.
> >
> > Tired: subsystem: Add driver XXX
> > Wired: subsystem: XXX: Add driver for XXX
> >
> >  drivers/mtd/nand/raw/loongson1-nand-controller.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/mtd/nand/raw/loongson1-nand-controller.c b/drivers/mtd/nand/raw/loongson1-nand-controller.c
> > index 6a369b1c7d86..8754bb4f8b56 100644
> > --- a/drivers/mtd/nand/raw/loongson1-nand-controller.c
> > +++ b/drivers/mtd/nand/raw/loongson1-nand-controller.c
> > @@ -371,7 +371,7 @@ static int ls1x_nand_dma_transfer(struct ls1x_nand_host *host, struct ls1x_nand_
> >         desc = dmaengine_prep_slave_single(chan, dma_addr, op->len, xfer_dir, DMA_PREP_INTERRUPT);
> >         if (!desc) {
> >                 dev_err(dev, "failed to prepare DMA descriptor\n");
> > -               ret = PTR_ERR(desc);
> > +               ret = -ENOMEM;
> 
> Thank you for fixing this issue.
> However, I believe -EIO is more appropriate than -ENOMEM, since
> dmaengine_prep_slave_single() can return errors other than -ENOMEM.
> 

It's not an I/O error so -EIO isn't correct.

There are a bunch of reasons it could fail but most likely
dma_pool_alloc() failed.  I think -ENOMEM is correct.

regards,
dan carpenter