[PATCH] platform/x86: wmi: replace usage of found with dedicated list iterator variable

[PATCH] platform/x86: wmi: replace usage of found with dedicated list iterator variable

[Jakob Koschel]

To move the list iterator variable into the list_for_each_entry_*()
macro in the future it should be avoided to use the list iterator
variable after the loop body.

To *never* use the list iterator variable after the loop it was
concluded to use a separate iterator variable instead of a
found boolean [1].

This removes the need to use a found variable and simply checking if
the variable was set, can determine if the break/goto was hit.

Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/
Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
---
 drivers/platform/x86/wmi.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
index 58a23a9adbef..aed293b5af81 100644
--- a/drivers/platform/x86/wmi.c
+++ b/drivers/platform/x86/wmi.c
@@ -1308,21 +1308,20 @@ acpi_wmi_ec_space_handler(u32 function, acpi_physical_address address,
 static void acpi_wmi_notify_handler(acpi_handle handle, u32 event,
 				    void *context)
 {
-	struct wmi_block *wblock;
-	bool found_it = false;
+	struct wmi_block *wblock = NULL, *iter;
 
-	list_for_each_entry(wblock, &wmi_block_list, list) {
-		struct guid_block *block = &wblock->gblock;
+	list_for_each_entry(iter, &wmi_block_list, list) {
+		struct guid_block *block = &iter->gblock;
 
-		if (wblock->acpi_device->handle == handle &&
+		if (iter->acpi_device->handle == handle &&
 		    (block->flags & ACPI_WMI_EVENT) &&
 		    (block->notify_id == event)) {
-			found_it = true;
+			wblock = iter;
 			break;
 		}
 	}
 
-	if (!found_it)
+	if (!wblock)
 		return;
 
 	/* If a driver is bound, then notify the driver. */

base-commit: f443e374ae131c168a065ea1748feac6b2e76613
-- 
2.25.1

Re: [PATCH] platform/x86: wmi: replace usage of found with dedicated list iterator variable

[Hans de Goede]

Hi,

On 3/24/22 08:20, Jakob Koschel wrote:
> To move the list iterator variable into the list_for_each_entry_*()
> macro in the future it should be avoided to use the list iterator
> variable after the loop body.
> 
> To *never* use the list iterator variable after the loop it was
> concluded to use a separate iterator variable instead of a
> found boolean [1].
> 
> This removes the need to use a found variable and simply checking if
> the variable was set, can determine if the break/goto was hit.
> 
> Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/
> Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>

Thank you for your patch, I've applied this patch to my review-hans 
branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans

Note it will show up in my review-hans branch once I've pushed my
local branch there, which might take a while.

Once I've run some tests on this branch the patches there will be
added to the platform-drivers-x86/for-next branch and eventually
will be included in the pdx86 pull-request to Linus for the next
merge-window.

Regards,

Hans


> ---
>  drivers/platform/x86/wmi.c | 13 ++++++-------
>  1 file changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
> index 58a23a9adbef..aed293b5af81 100644
> --- a/drivers/platform/x86/wmi.c
> +++ b/drivers/platform/x86/wmi.c
> @@ -1308,21 +1308,20 @@ acpi_wmi_ec_space_handler(u32 function, acpi_physical_address address,
>  static void acpi_wmi_notify_handler(acpi_handle handle, u32 event,
>  				    void *context)
>  {
> -	struct wmi_block *wblock;
> -	bool found_it = false;
> +	struct wmi_block *wblock = NULL, *iter;
>  
> -	list_for_each_entry(wblock, &wmi_block_list, list) {
> -		struct guid_block *block = &wblock->gblock;
> +	list_for_each_entry(iter, &wmi_block_list, list) {
> +		struct guid_block *block = &iter->gblock;
>  
> -		if (wblock->acpi_device->handle == handle &&
> +		if (iter->acpi_device->handle == handle &&
>  		    (block->flags & ACPI_WMI_EVENT) &&
>  		    (block->notify_id == event)) {
> -			found_it = true;
> +			wblock = iter;
>  			break;
>  		}
>  	}
>  
> -	if (!found_it)
> +	if (!wblock)
>  		return;
>  
>  	/* If a driver is bound, then notify the driver. */
> 
> base-commit: f443e374ae131c168a065ea1748feac6b2e76613