This is a note to let you know that I've just added the patch titled
powerpc: Check !irq instead of irq == NO_IRQ and remove NO_IRQ
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
powerpc-check-irq-instead-of-irq-no_irq-and-remove-n.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit b653f9325500ff5e88cf988bcd11dbc766a1ebfb
Author: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Date: Mon Jan 23 13:26:46 2023 +0100
powerpc: Check !irq instead of irq == NO_IRQ and remove NO_IRQ
[ Upstream commit bab537805a10bdbf55b31324ba4a9599e0651e5e ]
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://lore.kernel.org/all/Pine.LNX.4.64.0511211150040.13959@xxxxxxxxxxx
He re-iterated the same view recently in
https://lore.kernel.org/all/CAHk-=wg2Pkb9kbfbstbB91AJA2SF6cySbsgHG-iQMq56j3VTcA@xxxxxxxxxxxxxx
So test !irq instead of tesing irq == NO_IRQ.
All other usage of NO_IRQ for powerpc were removed in previous cycles so
the time has come to remove NO_IRQ completely for powerpc.
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/4b8d4f96140af01dec3a3330924dda8b2451c316.1674476798.git.christophe.leroy@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/powerpc/include/asm/irq.h b/arch/powerpc/include/asm/irq.h
index 2b3278534bc14..858393f7fd7d7 100644
--- a/arch/powerpc/include/asm/irq.h
+++ b/arch/powerpc/include/asm/irq.h
@@ -16,9 +16,6 @@
extern atomic_t ppc_n_lost_interrupts;
-/* This number is used when no interrupt has been assigned */
-#define NO_IRQ (0)
-
/* Total number of virq in the platform */
#define NR_IRQS CONFIG_NR_IRQS
diff --git a/arch/powerpc/platforms/44x/fsp2.c b/arch/powerpc/platforms/44x/fsp2.c
index 823397c802def..f8bbe05d9ef29 100644
--- a/arch/powerpc/platforms/44x/fsp2.c
+++ b/arch/powerpc/platforms/44x/fsp2.c
@@ -205,7 +205,7 @@ static void node_irq_request(const char *compat, irq_handler_t errirq_handler)
for_each_compatible_node(np, NULL, compat) {
irq = irq_of_parse_and_map(np, 0);
- if (irq == NO_IRQ) {
+ if (!irq) {
pr_err("device tree node %pOFn is missing a interrupt",
np);
of_node_put(np);
