* [PATCH v2] usb: Check !irq instead of irq == NO_IRQ
@ 2022-11-10 17:54 Christophe Leroy
2022-11-10 18:39 ` Alan Stern
0 siblings, 1 reply; 2+ messages in thread
From: Christophe Leroy @ 2022-11-10 17:54 UTC (permalink / raw)
To: Alan Stern, Greg Kroah-Hartman; +Cc: Christophe Leroy, linux-kernel, linux-usb
NO_IRQ is a relic from the old days. It is not used anymore in core
functions. By the way, function irq_of_parse_and_map() returns value 0
on error.
In some drivers, NO_IRQ is erroneously used to check the return of
irq_of_parse_and_map().
It is not a real bug today because the only architectures using the
drivers being fixed by this patch define NO_IRQ as 0, but there are
architectures which define NO_IRQ as -1. If one day those
architectures start using the non fixed drivers, there will be a
problem.
Long time ago Linus advocated for not using NO_IRQ, see
https://lkml.org/lkml/2005/11/21/221 . He re-iterated the same view
recently in https://lkml.org/lkml/2022/10/12/622
So test !irq instead of tesing irq == NO_IRQ.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
drivers/usb/host/ehci-grlib.c | 2 +-
drivers/usb/host/ehci-ppc-of.c | 2 +-
drivers/usb/host/fhci-hcd.c | 2 +-
drivers/usb/host/ohci-ppc-of.c | 2 +-
drivers/usb/host/uhci-grlib.c | 2 +-
5 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/usb/host/ehci-grlib.c b/drivers/usb/host/ehci-grlib.c
index a2c3b4ec8a8b..0717f2ccf49d 100644
--- a/drivers/usb/host/ehci-grlib.c
+++ b/drivers/usb/host/ehci-grlib.c
@@ -99,7 +99,7 @@ static int ehci_hcd_grlib_probe(struct platform_device *op)
hcd->rsrc_len = resource_size(&res);
irq = irq_of_parse_and_map(dn, 0);
- if (irq == NO_IRQ) {
+ if (!irq) {
dev_err(&op->dev, "%s: irq_of_parse_and_map failed\n",
__FILE__);
rv = -EBUSY;
diff --git a/drivers/usb/host/ehci-ppc-of.c b/drivers/usb/host/ehci-ppc-of.c
index 28a19693c19f..62a0a193798c 100644
--- a/drivers/usb/host/ehci-ppc-of.c
+++ b/drivers/usb/host/ehci-ppc-of.c
@@ -119,7 +119,7 @@ static int ehci_hcd_ppc_of_probe(struct platform_device *op)
hcd->rsrc_len = resource_size(&res);
irq = irq_of_parse_and_map(dn, 0);
- if (irq == NO_IRQ) {
+ if (!irq) {
dev_err(&op->dev, "%s: irq_of_parse_and_map failed\n",
__FILE__);
rv = -EBUSY;
diff --git a/drivers/usb/host/fhci-hcd.c b/drivers/usb/host/fhci-hcd.c
index 95a44462bed0..64a64140c2fd 100644
--- a/drivers/usb/host/fhci-hcd.c
+++ b/drivers/usb/host/fhci-hcd.c
@@ -676,7 +676,7 @@ static int of_fhci_probe(struct platform_device *ofdev)
/* USB Host interrupt. */
usb_irq = irq_of_parse_and_map(node, 0);
- if (usb_irq == NO_IRQ) {
+ if (!usb_irq) {
dev_err(dev, "could not get usb irq\n");
ret = -EINVAL;
goto err_usb_irq;
diff --git a/drivers/usb/host/ohci-ppc-of.c b/drivers/usb/host/ohci-ppc-of.c
index 591f675cc930..f2f6c832ec98 100644
--- a/drivers/usb/host/ohci-ppc-of.c
+++ b/drivers/usb/host/ohci-ppc-of.c
@@ -120,7 +120,7 @@ static int ohci_hcd_ppc_of_probe(struct platform_device *op)
}
irq = irq_of_parse_and_map(dn, 0);
- if (irq == NO_IRQ) {
+ if (!irq) {
dev_err(&op->dev, "%s: irq_of_parse_and_map failed\n",
__FILE__);
rv = -EBUSY;
diff --git a/drivers/usb/host/uhci-grlib.c b/drivers/usb/host/uhci-grlib.c
index 3ef6d52839e5..907d5f01edfd 100644
--- a/drivers/usb/host/uhci-grlib.c
+++ b/drivers/usb/host/uhci-grlib.c
@@ -116,7 +116,7 @@ static int uhci_hcd_grlib_probe(struct platform_device *op)
hcd->rsrc_len = resource_size(&res);
irq = irq_of_parse_and_map(dn, 0);
- if (irq == NO_IRQ) {
+ if (!irq) {
printk(KERN_ERR "%s: irq_of_parse_and_map failed\n", __FILE__);
rv = -EBUSY;
goto err_usb;
--
2.37.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] usb: Check !irq instead of irq == NO_IRQ
2022-11-10 17:54 [PATCH v2] usb: Check !irq instead of irq == NO_IRQ Christophe Leroy
@ 2022-11-10 18:39 ` Alan Stern
0 siblings, 0 replies; 2+ messages in thread
From: Alan Stern @ 2022-11-10 18:39 UTC (permalink / raw)
To: Christophe Leroy; +Cc: Greg Kroah-Hartman, linux-kernel, linux-usb
On Thu, Nov 10, 2022 at 06:54:35PM +0100, Christophe Leroy wrote:
> NO_IRQ is a relic from the old days. It is not used anymore in core
> functions. By the way, function irq_of_parse_and_map() returns value 0
> on error.
>
> In some drivers, NO_IRQ is erroneously used to check the return of
> irq_of_parse_and_map().
>
> It is not a real bug today because the only architectures using the
> drivers being fixed by this patch define NO_IRQ as 0, but there are
> architectures which define NO_IRQ as -1. If one day those
> architectures start using the non fixed drivers, there will be a
> problem.
>
> Long time ago Linus advocated for not using NO_IRQ, see
> https://lkml.org/lkml/2005/11/21/221 . He re-iterated the same view
> recently in https://lkml.org/lkml/2022/10/12/622
>
> So test !irq instead of tesing irq == NO_IRQ.
>
> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> ---
> drivers/usb/host/ehci-grlib.c | 2 +-
> drivers/usb/host/ehci-ppc-of.c | 2 +-
> drivers/usb/host/fhci-hcd.c | 2 +-
> drivers/usb/host/ohci-ppc-of.c | 2 +-
> drivers/usb/host/uhci-grlib.c | 2 +-
> 5 files changed, 5 insertions(+), 5 deletions(-)
For the [eou]hci-* files:
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Alan Stern
^ permalink raw reply [flat|nested] 2+ messages in thread
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