Re: [PATCH] ARM: s3c: irq-s3c24xx: Fix return value check for s3c24xx_init_intc()
From: Jackie Liu <hidden>
Date: 2021-09-01 12:30:59
Hi Krzysztof, Thanks for you message. ��� 2021/9/1 ������8:09, Krzysztof Kozlowski ������:
On 31/08/2021 11:57, Jackie Liu wrote:quoted
From: Jackie Liu <redacted> The s3c24xx_init_intc() returns an error pointer upon failure, not NULL. let's add an error pointer check in s3c24xx_handle_irq. Fixes: 1f629b7a3ced ("ARM: S3C24XX: transform irq handling into a declarative form") Signed-off-by: Jackie Liu <redacted>Please use scripts/get_maintainers.pl to get list of mailing lists to CC. You skipped two - arm and LKML.quoted
--- arch/arm/mach-s3c/irq-s3c24xx.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)diff --git a/arch/arm/mach-s3c/irq-s3c24xx.c b/arch/arm/mach-s3c/irq-s3c24xx.c index 0c631c14a817..d58bf0f9bf9a 100644 --- a/arch/arm/mach-s3c/irq-s3c24xx.c +++ b/arch/arm/mach-s3c/irq-s3c24xx.c@@ -362,11 +362,11 @@ static inline int s3c24xx_handle_intc(struct s3c_irq_intc *intc, static asmlinkage void __exception_irq_entry s3c24xx_handle_irq(struct pt_regs *regs) { do { - if (likely(s3c_intc[0])) + if (likely(!IS_ERR_OR_NULL(s3c_intc[0]))) if (s3c24xx_handle_intc(s3c_intc[0], regs, 0))Thanks for the patch but it does not look entirely correct. For platform based machines, neither ERR nor NULL can happen here. The s3c24xx_handle_irq() will be set as IRQ handler iff this succeeds: s3c_intc[0] = s3c24xx_init_intc() If this fails, the next calls to s3c24xx_init_intc() won't be executed. For DT machine, s3c_init_intc_of() could set the IRQ handler without setting s3c_intc[0] only if it was called with num_ctrl=0. There is no such code path, so again the s3c_intc[0] will have a valid pointer if set_handle_irq() is called. Therefore in s3c24xx_handle_irq(), the s3c_intc[0] is always something. The code can be simplified by removing if(), if we really wanted and were sure about it.
In fact, I didn't study his underlying logic in depth, but found that this place was not particularly perfect based on the return value of the function, because I happened to encounter a similar problem elsewhere.
quoted
continue; - if (s3c_intc[2]) + if (!IS_ERR_OR_NULL(s3c_intc[2]))For the non-DT case, this seems ugly but proper solution. The s3c_intc[2] could be NULL (not set at all) or set as ERR (if s3c24xx_init_intc() fails).quoted
if (s3c24xx_handle_intc(s3c_intc[2], regs, 64)) continue;Best regards, Krzysztof
Would you mind review v2? --------------------------------------------------------------
diff --git a/arch/arm/mach-s3c/irq-s3c24xx.c b/arch/arm/mach-s3c/irq-s3c24xx.c index 0c631c14a817..df471d322493 100644
--- a/arch/arm/mach-s3c/irq-s3c24xx.c
+++ b/arch/arm/mach-s3c/irq-s3c24xx.c@@ -362,11 +362,24 @@ static inline int s3c24xx_handle_intc(struct s3c_irq_intc *intc,
static asmlinkage void __exception_irq_entry s3c24xx_handle_irq(struct
pt_regs *regs)
{
do {
- if (likely(s3c_intc[0]))
- if (s3c24xx_handle_intc(s3c_intc[0], regs, 0))
- continue;
+ /* For platform based machines, neither ERR nor NULL can
happen here.
+ * The s3c24xx_handle_irq() will be set as IRQ handler
iff this succeeds:
+ *
+ * s3c_intc[0] = s3c24xx_init_intc()
+ *
+ * If this fails, the next calls to s3c24xx_init_intc()
won't be executed.
+ *
+ * For DT machine, s3c_init_intc_of() could set the IRQ
handler without
+ * setting s3c_intc[0] only if it was called with
num_ctrl=0. There is no
+ * such code path, so again the s3c_intc[0] will have a
valid pointer if
+ * set_handle_irq() is called.
+ *
+ * Therefore in s3c24xx_handle_irq(), the s3c_intc[0] is
always something.
+ */
+ if (s3c24xx_handle_intc(s3c_intc[0], regs, 0))
+ continue;
- if (s3c_intc[2])
+ if (!IS_ERR_OR_NULL(s3c_intc[2]))
if (s3c24xx_handle_intc(s3c_intc[2], regs, 64))
continue;
---
Thanks, Jackie