Re: [PATCH 1 4/4] PCI: rcar: Use of_device_get_match_data() to simplify probe

[Simon Horman]

On Tue, Jan 31, 2017 at 02:20:20PM -0600, Bjorn Helgaas wrote:
> This is a DT-only driver, so the only way to call rcar_pcie_probe() is to
> match an entry in rcar_pcie_of_match[], so of_id cannot be NULL.
> 
> Furthermore, of_id->data can only be NULL if an rcar_pcie_of_match[] entry
> has a NULL .data member.  That's a driver defect, and we don't want to
> return -EINVAL, which is easy to ignore.  We'd rather take the NULL pointer
> dereference so we notice the problem and fix it.
> 
> Use of_device_get_match_data() to retrieve the hw_init_fn pointer.  No
> functional change intended.
> 
> Suggested-by: Geert Uytterhoeven 
> Signed-off-by: Bjorn Helgaas 

Acked-by: Simon Horman 

> ---
>  drivers/pci/host/pcie-rcar.c |7 +--
>  1 file changed, 1 insertion(+), 6 deletions(-)
> 
> diff --git a/drivers/pci/host/pcie-rcar.c b/drivers/pci/host/pcie-rcar.c
> index aca85be101f8..b3b6d5273347 100644
> --- a/drivers/pci/host/pcie-rcar.c
> +++ b/drivers/pci/host/pcie-rcar.c
> @@ -1125,7 +1125,6 @@ static int rcar_pcie_probe(struct platform_device *pdev)
>   struct device *dev = &pdev->dev;
>   struct rcar_pcie *pcie;
>   unsigned int data;
> - const struct of_device_id *of_id;
>   int err;
>   int (*hw_init_fn)(struct rcar_pcie *);
>  
> @@ -1149,11 +1148,6 @@ static int rcar_pcie_probe(struct platform_device 
> *pdev)
>   if (err)
>   return err;
>  
> - of_id = of_match_device(rcar_pcie_of_match, dev);
> - if (!of_id || !of_id->data)
> - return -EINVAL;
> - hw_init_fn = of_id->data;
> -
>   pm_runtime_enable(dev);
>   err = pm_runtime_get_sync(dev);
>   if (err < 0) {
> @@ -1162,6 +1156,7 @@ static int rcar_pcie_probe(struct platform_device *pdev)
>   }
>  
>   /* Failure to get a link might just be that no cards are inserted */
> + hw_init_fn = of_device_get_match_data(dev);
>   err = hw_init_fn(pcie);
>   if (err) {
>   dev_info(dev, "PCIe link down\n");
> 

[PATCH 1 4/4] PCI: rcar: Use of_device_get_match_data() to simplify probe

[Bjorn Helgaas]

This is a DT-only driver, so the only way to call rcar_pcie_probe() is to
match an entry in rcar_pcie_of_match[], so of_id cannot be NULL.

Furthermore, of_id->data can only be NULL if an rcar_pcie_of_match[] entry
has a NULL .data member.  That's a driver defect, and we don't want to
return -EINVAL, which is easy to ignore.  We'd rather take the NULL pointer
dereference so we notice the problem and fix it.

Use of_device_get_match_data() to retrieve the hw_init_fn pointer.  No
functional change intended.

Suggested-by: Geert Uytterhoeven 
Signed-off-by: Bjorn Helgaas 
---
 drivers/pci/host/pcie-rcar.c |7 +--
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/drivers/pci/host/pcie-rcar.c b/drivers/pci/host/pcie-rcar.c
index aca85be101f8..b3b6d5273347 100644
--- a/drivers/pci/host/pcie-rcar.c
+++ b/drivers/pci/host/pcie-rcar.c
@@ -1125,7 +1125,6 @@ static int rcar_pcie_probe(struct platform_device *pdev)
struct device *dev = &pdev->dev;
struct rcar_pcie *pcie;
unsigned int data;
-   const struct of_device_id *of_id;
int err;
int (*hw_init_fn)(struct rcar_pcie *);
 
@@ -1149,11 +1148,6 @@ static int rcar_pcie_probe(struct platform_device *pdev)
if (err)
return err;
 
-   of_id = of_match_device(rcar_pcie_of_match, dev);
-   if (!of_id || !of_id->data)
-   return -EINVAL;
-   hw_init_fn = of_id->data;
-
pm_runtime_enable(dev);
err = pm_runtime_get_sync(dev);
if (err < 0) {
@@ -1162,6 +1156,7 @@ static int rcar_pcie_probe(struct platform_device *pdev)
}
 
/* Failure to get a link might just be that no cards are inserted */
+   hw_init_fn = of_device_get_match_data(dev);
err = hw_init_fn(pcie);
if (err) {
dev_info(dev, "PCIe link down\n");