在 2012-12-11二的 08:30 +0000，Grant Likely写道： > On Tue, 27 Nov 2012 09:41:46 +0800, Mike <qiud...@linux.vnet.ibm.com> wrote: > > 在 2012-11-26一的 20:17 +0000，Grant Likely写道： > > > On Mon, 24 Sep 2012 17:37:55 +0800, Mike Qiu <qiud...@linux.vnet.ibm.com> > > > wrote: > > > > Function irq_create_mapping() calls irq_find_mapping(). The later > > > > function has checked if the indicated IRQ domain has hw IRQ mapped to > > > > virtual IRQ through legacy mode or not and return the value of the > > > > legacy irq number by call irq_domain_legacy_revmap(). We needn't > > > > to call irq_domain_legacy_revmap() to do same check in > > > > irq_create_mapping() again. > > > > > > > > The patch removes the duplicate call. > > > > > > > > Signed-off-by: Mike Qiu <qiud...@linux.vnet.ibm.com> > > > > --- > > > > kernel/irq/irqdomain.c | 7 +++++-- > > > > 1 files changed, 5 insertions(+), 2 deletions(-) > > > > > > > > diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c > > > > index 49a7772..286d672 100644 > > > > --- a/kernel/irq/irqdomain.c > > > > +++ b/kernel/irq/irqdomain.c > > > > @@ -547,9 +547,12 @@ unsigned int irq_create_mapping(struct irq_domain > > > > *domain, > > > > return virq; > > > > } > > > > > > > > - /* Get a virtual interrupt number */ > > > > + /* > > > > + * For IRQ domain with type of IRQ_DOMAIN_MAP_LEGACY, we needn't > > > > + * create the IRQ mapping for non-existing one, so just return > > > > 0. > > > > + */ > > > > if (domain->revmap_type == IRQ_DOMAIN_MAP_LEGACY) > > > > - return irq_domain_legacy_revmap(domain, hwirq); > > > > + return 0; > > > > > > But it does need to return the virq assigned to the hwirq. That is why > > > it has to call the revmap function. > > > > > Yes, thanks > > > > this judgment has been done in > > /*Check if mapping already exists*/ > > virq = irq_find_mapping(domain, hwirq); > > > > if the virq equals none zero, the func irq_create_mapping will > > return the virq value directly(already exists). > > > > otherwise, that means virq equals zero, this has two meanings, one is > > haven't find the already exist mapping, the other one is in > > irq_find_mapping() > > case IRQ_DOMAIN_MAP_LEGACY: > > return irq_domain_legacy_revmap(domain, hwirq); > > this may return zero. > > > > So, when we check if it is a IRQ_DOMAIN_MAP_LEGACY, we just return zero > > is OK. because if it is none zero, it will be return after check if > > mapping already exists, and never come here. also we never try to assign > > the virq for the legacy map. > > > > I don't know if you have understand my explanation. > > Yes, your explanation makes sense and you are correct. I'm not going to > apply this for v3.8 (I've left it too late before the merge window), but > I'll look again after the merge window closes. > > g. > OK, fair enough. Thanks
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