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irq: add irq_alloc_desc_between() helper

PATCH In review Grant Likely 1 participant 2 messages May 4, 2011 IRQ

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Grant Likely

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#0 lore raw

PATCH 1/1 irq: add irq_alloc_desc_between() helper

Written in response to conversation on IRC about needing to specify an upper limit on the virq value returned for some MSI interrupt controllers. Compiled only; untested

Signed-off-by Grant Likely <[email protected]>
---
 include/linux/irq.h  |    9 ++++++++-
 kernel/irq/irqdesc.c |    5 ++++-
 2 files changed, 12 insertions(+), 2 deletions(-)
include/linux/irq.h +8 -1
index 09a3080..bcb712b 100644
@@ -544,10 +544,17 @@ static inline struct msi_desc *irq_data_get_msi(struct irq_data *d)
 	return d->msi_desc;
 }
 
-int irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node);
+int irq_alloc_descs_between(int irq, unsigned int from, unsigned int cnt,
+			    unsigned int max, int node);
 void irq_free_descs(unsigned int irq, unsigned int cnt);
 int irq_reserve_irqs(unsigned int from, unsigned int cnt);
 
+static inline int irq_alloc_descs(int irq, unsigned int from, unsigned int cnt,
+				  int node)
+{
+	return irq_alloc_descs_between(irq, from, cnt, 0, node);
+}
+
 static inline int irq_alloc_desc(int node)
 {
 	return irq_alloc_descs(-1, 0, 1, node);
kernel/irq/irqdesc.c +4 -1
index 2c039c9..c1ddabd 100644
@@ -322,7 +322,7 @@ void irq_free_descs(unsigned int from, unsigned int cnt)
  * Returns the first irq number or error code
  */
 int __ref
-irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node)
+irq_alloc_descs_between(int irq, unsigned int from, unsigned int cnt, unsigned int max, int node)
 {
 	int start, ret;
 

@@ -337,6 +337,9 @@ irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node)
 	if (irq >=0 && start != irq)
 		goto err;
 
+	if (max && start + cnt >= max)
+		goto err;
+
 	if (start + cnt > nr_irqs) {
 		ret = irq_expand_nr_irqs(start + cnt);
 		if (ret)
author
#1 lore raw
Quoted 47 lines · Grant Likely

Written in response to conversation on IRC about needing to specify an upper limit on the virq value returned for some MSI interrupt controllers.  Compiled only; untested

Signed-off-by Grant Likely <[email protected]>

---
 include/linux/irq.h  |    9 ++++++++-
 kernel/irq/irqdesc.c |    5 ++++-

 2 files changed, 12 insertions(+), 2 deletions(-)
include/linux/irq.h +8 -1
index 09a3080..bcb712b 100644
@@ -544,10 +544,17 @@ static inline struct msi_desc *irq_data_get_msi(struct irq_data *d)
        return d->msi_desc;
  }
 
-int irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node);
+int irq_alloc_descs_between(int irq, unsigned int from, unsigned int cnt,
+                           unsigned int max, int node);
  void irq_free_descs(unsigned int irq, unsigned int cnt);
  int irq_reserve_irqs(unsigned int from, unsigned int cnt);
 
+static inline int irq_alloc_descs(int irq, unsigned int from, unsigned int cnt,
+                                 int node)
+{
+       return irq_alloc_descs_between(irq, from, cnt, 0, node);
+}
+
  static inline int irq_alloc_desc(int node)
  {
        return irq_alloc_descs(-1, 0, 1, node);
kernel/irq/irqdesc.c +0 -0
index 2c039c9..c1ddabd 100644
@@ -322,7 +322,7 @@ void irq_free_descs(unsigned int from, unsigned int cnt)
  * Returns the first irq number or error code
  */

 int __ref

kernel/irq/irqdesc.c +1 -1
-irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node)
+irq_alloc_descs_between(int irq, unsigned int from, unsigned int cnt, unsigned int max, int node)

 {
       int start, ret;

kernel/irq/irqdesc.c irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node) · line 340

Quoted 4 lines
kernel/irq/irqdesc.c +1 -0
@@ -337,6 +337,9 @@ irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node)
        if (irq >=0 && start != irq)
                goto err;
 
+       if (max && start + cnt >= max)

Actually, this should be 'if (max && start + cnt > max)'

g.