Xen devel - Feb 2013 - [PATCH v2 15/26] xen, irq: call irq_realloc_desc_at() at first

We will pre-reserve irq for all gsi at first for x86, so we have to
use realloc with it.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: xen-devel@lists.xensource.com
---
 drivers/xen/events.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 0be4df3..dda38db 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -482,8 +482,12 @@ static int __must_check xen_allocate_irq_gsi(unsigned gsi)
 	/* Legacy IRQ descriptors are already allocated by the arch. */
 	if (gsi < NR_IRQS_LEGACY)
 		irq = gsi;
-	else
-		irq = irq_alloc_desc_at(gsi, -1);
+	else {
+		/* for x86, irq already get reserved for gsi */
+		irq = irq_realloc_desc_at(gsi, -1);
+		if (irq < 0)
+			irq = irq_alloc_desc_at(gsi, -1);
+	}
 
 	xen_irq_init(irq);
 
-- 
1.7.10.4

On Fri, Feb 08, 2013 at 11:28:12AM -0800, Yinghai Lu
wrote:
> We will pre-reserve irq for all gsi at first for x86, so we have to
> use realloc with it.
Where are the GSI''s pre-allocated?
> 
> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Cc: xen-devel@lists.xensource.com
> ---
>  drivers/xen/events.c |    8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/xen/events.c b/drivers/xen/events.c
> index 0be4df3..dda38db 100644
> --- a/drivers/xen/events.c
> +++ b/drivers/xen/events.c
> @@ -482,8 +482,12 @@ static int __must_check xen_allocate_irq_gsi(unsigned
gsi)
>  	/* Legacy IRQ descriptors are already allocated by the arch. */
>  	if (gsi < NR_IRQS_LEGACY)
>  		irq = gsi;
> -	else
> -		irq = irq_alloc_desc_at(gsi, -1);
> +	else {
> +		/* for x86, irq already get reserved for gsi */
> +		irq = irq_realloc_desc_at(gsi, -1);
> +		if (irq < 0)
> +			irq = irq_alloc_desc_at(gsi, -1);
> +	}
>  
>  	xen_irq_init(irq);
>  
> -- 
> 1.7.10.4
>

On Fri, Mar 8, 2013 at 11:43 AM, Konrad Rzeszutek Wilk
<konrad.wilk@oracle.com> wrote:
> On Fri, Feb 08, 2013 at 11:28:12AM -0800, Yinghai Lu wrote:
>> We will pre-reserve irq for all gsi at first for x86, so we have to
>> use realloc with it.
>
> Where are the GSI''s pre-allocated?
In following patch.

I put this one forward, so it will not break git bisecting.

On Fri, Mar 08, 2013 at 02:43:57PM -0500, Konrad Rzeszutek Wilk
wrote:
> On Fri, Feb 08, 2013 at 11:28:12AM -0800, Yinghai Lu wrote:
> > We will pre-reserve irq for all gsi at first for x86, so we have to
> > use realloc with it.
> 
> Where are the GSI''s pre-allocated?
And the answer is in arch_probe_nr_irqs and determined by nr_irqs_gsi.
That data then feeds in early_irq_init which sets the bitmap.

Could you add that please in the git commit if it is not too much
trouble?
> 
> > 
> > Signed-off-by: Yinghai Lu <yinghai@kernel.org>
> > Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> > Cc: xen-devel@lists.xensource.com
> > ---
> >  drivers/xen/events.c |    8 ++++++--
> >  1 file changed, 6 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/xen/events.c b/drivers/xen/events.c
> > index 0be4df3..dda38db 100644
> > --- a/drivers/xen/events.c
> > +++ b/drivers/xen/events.c
> > @@ -482,8 +482,12 @@ static int __must_check
xen_allocate_irq_gsi(unsigned gsi)
> >  	/* Legacy IRQ descriptors are already allocated by the arch. */
> >  	if (gsi < NR_IRQS_LEGACY)
> >  		irq = gsi;
> > -	else
> > -		irq = irq_alloc_desc_at(gsi, -1);
> > +	else {
> > +		/* for x86, irq already get reserved for gsi */
> > +		irq = irq_realloc_desc_at(gsi, -1);
> > +		if (irq < 0)
> > +			irq = irq_alloc_desc_at(gsi, -1);
> > +	}
> >  
> >  	xen_irq_init(irq);
> >  
> > -- 
> > 1.7.10.4
> >