lkml.org 
[lkml]   [2013]   [Jul]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Subject[PATCH RFC] genirq: Genric chip: Use DIV_ROUND_UP to count numchips
From
Date
The number of interrupts in a domain may be not divisible by the number of
interrupts each chip handles.
Integer division may truncate the result, thus use DIV_ROUND_UP to count
numchips.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
---
Seems all users of irq_alloc_domain_generic_chips() in current code do not
have this issue. I just found the issue while reading the code.

In the commit 02c981c0 of "ARM: CSR: Adding CSR SiRFprimaII board support"
It set SIRFSOC_INTENAL_IRQ_END to 59.
So I think this might be a possible case for some hardware.

kernel/irq/generic-chip.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/irq/generic-chip.c b/kernel/irq/generic-chip.c
index 10e663a..452d6f2 100644
--- a/kernel/irq/generic-chip.c
+++ b/kernel/irq/generic-chip.c
@@ -275,7 +275,7 @@ int irq_alloc_domain_generic_chips(struct irq_domain *d, int irqs_per_chip,
if (d->gc)
return -EBUSY;

- numchips = d->revmap_size / irqs_per_chip;
+ numchips = DIV_ROUND_UP(d->revmap_size, irqs_per_chip);
if (!numchips)
return -EINVAL;

--
1.8.1.2




\
 
 \ /
  Last update: 2013-07-05 12:01    [W:0.041 / U:1.804 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site