[next,v2,1/2] mmc: sunplus: Fix error handling in spmmc_drv_probe()

When mmc allocation succeeds, the error paths are not freeing mmc.

Fix the above issue by changing mmc_alloc_host() to devm_mmc_alloc_host()
to simplify the error handling. Remove label 'probe_free_host' as devm_*
api takes care of freeing, also remove mmc_free_host() from remove
function as devm_* takes care of freeing.

Fixes: 4e268fed8b18 ("mmc: Add mmc driver for Sunplus SP7021")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/all/a3829ed3-d827-4b9d-827e-9cc24a3ec3bc@moroto.mountain/
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
---
This is based on static analysis with smatch, only compile tested.

v1->v2: Simplify code by using devm_mmc_alloc_host() instead of
mmc_alloc_host() (Ulf Hansson's suggestion)
---
 drivers/mmc/host/sunplus-mmc.c | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

On Wed, 9 Aug 2023 at 09:18, Harshit Mogalapalli
<harshit.m.mogalapalli@oracle.com> wrote:
>
> When mmc allocation succeeds, the error paths are not freeing mmc.
>
> Fix the above issue by changing mmc_alloc_host() to devm_mmc_alloc_host()
> to simplify the error handling. Remove label 'probe_free_host' as devm_*
> api takes care of freeing, also remove mmc_free_host() from remove
> function as devm_* takes care of freeing.
>
> Fixes: 4e268fed8b18 ("mmc: Add mmc driver for Sunplus SP7021")
> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> Closes: https://lore.kernel.org/all/a3829ed3-d827-4b9d-827e-9cc24a3ec3bc@moroto.mountain/
> Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>

This doesn't apply on my next branch, please rebase it.

Moreover, it looks like you should replace a few more "goto
probe_free_host;" with "return ret;". Please have a closer look.

Kind regards
Uffe

> ---
> This is based on static analysis with smatch, only compile tested.
>
> v1->v2: Simplify code by using devm_mmc_alloc_host() instead of
> mmc_alloc_host() (Ulf Hansson's suggestion)
> ---
>  drivers/mmc/host/sunplus-mmc.c | 14 +++-----------
>  1 file changed, 3 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/mmc/host/sunplus-mmc.c b/drivers/mmc/host/sunplus-mmc.c
> index a55a87f64d2a..2bdebeb1f8e4 100644
> --- a/drivers/mmc/host/sunplus-mmc.c
> +++ b/drivers/mmc/host/sunplus-mmc.c
> @@ -863,11 +863,9 @@ static int spmmc_drv_probe(struct platform_device *pdev)
>         struct spmmc_host *host;
>         int ret = 0;
>
> -       mmc = mmc_alloc_host(sizeof(*host), &pdev->dev);
> -       if (!mmc) {
> -               ret = -ENOMEM;
> -               goto probe_free_host;
> -       }
> +       mmc = devm_mmc_alloc_host(&pdev->dev, sizeof(struct spmmc_host));
> +       if (!mmc)
> +               return -ENOMEM;
>
>         host = mmc_priv(mmc);
>         host->mmc = mmc;
> @@ -938,11 +936,6 @@ static int spmmc_drv_probe(struct platform_device *pdev)
>
>  clk_disable:
>         clk_disable_unprepare(host->clk);
> -
> -probe_free_host:
> -       if (mmc)
> -               mmc_free_host(mmc);
> -
>         return ret;
>  }
>
> @@ -956,7 +949,6 @@ static int spmmc_drv_remove(struct platform_device *dev)
>         pm_runtime_put_noidle(&dev->dev);
>         pm_runtime_disable(&dev->dev);
>         platform_set_drvdata(dev, NULL);
> -       mmc_free_host(host->mmc);
>
>         return 0;
>  }
> --
> 2.39.3
>

On Wed, 9 Aug 2023 at 09:19, Harshit Mogalapalli
<harshit.m.mogalapalli@oracle.com> wrote:
>
> The platform_get_irq() function returns negative error codes on failure.
>
> Fixes: 4e268fed8b18 ("mmc: Add mmc driver for Sunplus SP7021")
> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> Closes: https://lore.kernel.org/all/a3829ed3-d827-4b9d-827e-9cc24a3ec3bc@moroto.mountain/
> Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>

Applied for fixes and by adding a stable tag, thanks!

Kind regards
Uffe


> ---
> v1->v2: Split into two patches as they are doing different things.
>
> This is based on static analysis with smatch, only compile tested.
> ---
>  drivers/mmc/host/sunplus-mmc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sunplus-mmc.c b/drivers/mmc/host/sunplus-mmc.c
> index 2bdebeb1f8e4..e9cb1a57cb75 100644
> --- a/drivers/mmc/host/sunplus-mmc.c
> +++ b/drivers/mmc/host/sunplus-mmc.c
> @@ -885,7 +885,7 @@ static int spmmc_drv_probe(struct platform_device *pdev)
>                 return dev_err_probe(&pdev->dev, PTR_ERR(host->rstc), "rst get fail\n");
>
>         host->irq = platform_get_irq(pdev, 0);
> -       if (host->irq <= 0)
> +       if (host->irq < 0)
>                 return host->irq;
>
>         ret = devm_request_threaded_irq(&pdev->dev, host->irq,
> --
> 2.39.3
>

On Wed, Aug 09, 2023 at 01:33:51PM +0200, Ulf Hansson wrote:
> On Wed, 9 Aug 2023 at 09:19, Harshit Mogalapalli
> <harshit.m.mogalapalli@oracle.com> wrote:
> >
> > The platform_get_irq() function returns negative error codes on failure.
> >
> > Fixes: 4e268fed8b18 ("mmc: Add mmc driver for Sunplus SP7021")
> > Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> > Closes: https://lore.kernel.org/all/a3829ed3-d827-4b9d-827e-9cc24a3ec3bc@moroto.mountain/
> > Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
> 
> Applied for fixes and by adding a stable tag, thanks!

It's not really a fix.  The platform_get_irq() function can't actually
return zero.

I asked Arnd about this and he said that there were some arches where
zero was a valid IRQ but they're not in the upstream kernel any more and
we're hopefully not going to do that again.

regards,
dan carpenter