On Fri, Aug 30, 2024 at 10:06:24AM +0800, Zhang Zekun wrote:
> __free() provides a scoped of_node_put() functionality to put the
> device_node automatically, and we don't need to call of_node_put()
> directly. Let's simplify the code a bit with the use of __free().
>
> Signed-off-by: Zhang Zekun <zhangzekun11@xxxxxxxxxx>
> ---
> drivers/of/device.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/of/device.c b/drivers/of/device.c
> index edf3be197265..7a71ef2aa16e 100644
> --- a/drivers/of/device.c
> +++ b/drivers/of/device.c
> @@ -35,7 +35,7 @@ EXPORT_SYMBOL(of_match_device);
> static void
> of_dma_set_restricted_buffer(struct device *dev, struct device_node *np)
> {
> - struct device_node *node, *of_node = dev->of_node;
> + struct device_node *of_node = dev->of_node;
> int count, i;
>
> if (!IS_ENABLED(CONFIG_DMA_RESTRICTED_POOL))
> @@ -54,17 +54,16 @@ of_dma_set_restricted_buffer(struct device *dev, struct device_node *np)
> }
>
> for (i = 0; i < count; i++) {
> - node = of_parse_phandle(of_node, "memory-region", i);
> + struct device_node *node __free(device_node) =
> + of_parse_phandle(of_node, "memory-region", i);
> /*
> * There might be multiple memory regions, but only one
> * restricted-dma-pool region is allowed.
> */
> if (of_device_is_compatible(node, "restricted-dma-pool") &&
> of_device_is_available(node)) {
> - of_node_put(node);
> break;
> }
> - of_node_put(node);
> }
Actually, I'd re-write this function like this (untested):
static void
of_dma_set_restricted_buffer(struct device *dev, struct device_node *np)
{
struct device_node *of_node = dev->of_node;
struct of_phandle_iterator it;
int rc, match = -1, i = 0;
if (!IS_ENABLED(CONFIG_DMA_RESTRICTED_POOL))
return;
/*
* If dev->of_node doesn't exist or doesn't contain memory-region, try
* the OF node having DMA configuration.
*/
if (!of_property_present(of_node, "memory-region"))
of_node = np;
of_for_each_phandle(&it, of_node, rc, "memory-region", NULL, 0) {
/*
* There might be multiple memory regions, but only one
* restricted-dma-pool region is allowed.
*/
if ((match < 0) && of_device_is_compatible(it.node, "restricted-dma-pool") &&
of_device_is_available(it.node)) {
match = i;
if (of_reserved_mem_device_init_by_idx(dev, of_node, i))
dev_warn(dev, "failed to initialise \"restricted-dma-pool\" memory node\n");
}
i++;
}
}
of_parse_phandle() is implemented using of_for_each_phandle(), so every
call to of_parse_phandle() is iterating i times.
Rob
