2022-07-19 10:22:14

by Andrey Strachuk

Subject: [PATCH] ACPI: remove useless comparisons in acpi_pci_link_check_possible(), acpi_pci_link_check_current()

Local variable 'p' is initialized by an address
of field of acpi_resource, so it does not make
sense to compare 'p' with NULL.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Andrey Strachuk <[email protected]>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
---
drivers/acpi/pci_link.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
index 58647051c948..aa1038b8aec4 100644
--- a/drivers/acpi/pci_link.c
+++ b/drivers/acpi/pci_link.c
@@ -95,7 +95,7 @@ static acpi_status acpi_pci_link_check_possible(struct acpi_resource *resource,
case ACPI_RESOURCE_TYPE_IRQ:
{
struct acpi_resource_irq *p = &resource->data.irq;
- if (!p || !p->interrupt_count) {
+ if (!p->interrupt_count) {
acpi_handle_debug(handle,
"Blank _PRS IRQ resource\n");
return AE_OK;
@@ -121,7 +121,7 @@ static acpi_status acpi_pci_link_check_possible(struct acpi_resource *resource,
{
struct acpi_resource_extended_irq *p =
&resource->data.extended_irq;
- if (!p || !p->interrupt_count) {
+ if (!p->interrupt_count) {
acpi_handle_debug(handle,
"Blank _PRS EXT IRQ resource\n");
return AE_OK;
@@ -182,7 +182,7 @@ static acpi_status acpi_pci_link_check_current(struct acpi_resource *resource,
case ACPI_RESOURCE_TYPE_IRQ:
{
struct acpi_resource_irq *p = &resource->data.irq;
- if (!p || !p->interrupt_count) {
+ if (!p->interrupt_count) {
/*
* IRQ descriptors may have no IRQ# bits set,
* particularly those w/ _STA disabled
@@ -197,7 +197,7 @@ static acpi_status acpi_pci_link_check_current(struct acpi_resource *resource,
{
struct acpi_resource_extended_irq *p =
&resource->data.extended_irq;
- if (!p || !p->interrupt_count) {
+ if (!p->interrupt_count) {
/*
* extended IRQ descriptors must
* return at least 1 IRQ
--
2.25.1

2022-07-19 20:49:08

by Bjorn Helgaas

Subject: Re: [PATCH] ACPI: remove useless comparisons in acpi_pci_link_check_possible(), acpi_pci_link_check_current()

Since this only affects pci_link.c, I would update the subject to
match the style of previous commits:

ACPI/PCI: Remove useless NULL pointer checks

On Tue, Jul 19, 2022 at 12:59:50PM +0300, Andrey Strachuk wrote:
> Local variable 'p' is initialized by an address
> of field of acpi_resource, so it does not make
> sense to compare 'p' with NULL.

Rewrap to fill 75 columns, which is the typical width of commit logs.

> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Signed-off-by: Andrey Strachuk <[email protected]>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")

I think you should drop this Fixes: tag because it's not useful.

Reviewed-by: Bjorn Helgaas <[email protected]>

> ---
> drivers/acpi/pci_link.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
> index 58647051c948..aa1038b8aec4 100644
> --- a/drivers/acpi/pci_link.c
> +++ b/drivers/acpi/pci_link.c
> @@ -95,7 +95,7 @@ static acpi_status acpi_pci_link_check_possible(struct acpi_resource *resource,
> case ACPI_RESOURCE_TYPE_IRQ:
> {
> struct acpi_resource_irq *p = &resource->data.irq;
> - if (!p || !p->interrupt_count) {
> + if (!p->interrupt_count) {
> acpi_handle_debug(handle,
> "Blank _PRS IRQ resource\n");
> return AE_OK;
> @@ -121,7 +121,7 @@ static acpi_status acpi_pci_link_check_possible(struct acpi_resource *resource,
> {
> struct acpi_resource_extended_irq *p =
> &resource->data.extended_irq;
> - if (!p || !p->interrupt_count) {
> + if (!p->interrupt_count) {
> acpi_handle_debug(handle,
> "Blank _PRS EXT IRQ resource\n");
> return AE_OK;
> @@ -182,7 +182,7 @@ static acpi_status acpi_pci_link_check_current(struct acpi_resource *resource,
> case ACPI_RESOURCE_TYPE_IRQ:
> {
> struct acpi_resource_irq *p = &resource->data.irq;
> - if (!p || !p->interrupt_count) {
> + if (!p->interrupt_count) {
> /*
> * IRQ descriptors may have no IRQ# bits set,
> * particularly those w/ _STA disabled
> @@ -197,7 +197,7 @@ static acpi_status acpi_pci_link_check_current(struct acpi_resource *resource,
> {
> struct acpi_resource_extended_irq *p =
> &resource->data.extended_irq;
> - if (!p || !p->interrupt_count) {
> + if (!p->interrupt_count) {
> /*
> * extended IRQ descriptors must
> * return at least 1 IRQ
> --
> 2.25.1
>