[PATCH] irqdesc: Consolidate irq reservation logic

From: Grant Likely
Date: Mon Jan 23 2012 - 16:09:06 EST


irq_reserve_irqs() and irq_alloc_descs() use largely identical code for
finding the range of irqs to reserve. This patch consolidates it into
a single function

v2: Fix bug where irq_alloc_desc() was returning -EEXIST always

Signed-off-by: Grant Likely <grant.likely@xxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
kernel/irq/irqdesc.c | 45 ++++++++++++++++++++++++---------------------
1 files changed, 24 insertions(+), 21 deletions(-)

diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index d86e254..11feb2f 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -339,18 +339,15 @@ void irq_free_descs(unsigned int from, unsigned int cnt)
EXPORT_SYMBOL_GPL(irq_free_descs);

/**
- * irq_alloc_descs - allocate and initialize a range of irq descriptors
+ * __irq_reserve_irqs() - reserve a range of irq numbers
* @irq: Allocate for specific irq number if irq >= 0
* @from: Start the search from this irq number
* @cnt: Number of consecutive irqs to allocate.
- * @node: Preferred node on which the irq descriptor should be allocated
- * @owner: Owning module (can be NULL)
*
* Returns the first irq number or error code
*/
-int __ref
-__irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node,
- struct module *owner)
+static int __ref
+__irq_reserve_irqs(int irq, unsigned int from, unsigned int cnt)
{
int start, ret;

@@ -379,12 +376,30 @@ __irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node,

bitmap_set(allocated_irqs, start, cnt);
mutex_unlock(&sparse_irq_lock);
- return alloc_descs(start, cnt, node, owner);
+ return start;

err:
mutex_unlock(&sparse_irq_lock);
return ret;
}
+
+/**
+ * irq_alloc_descs - allocate and initialize a range of irq descriptors
+ * @irq: Allocate for specific irq number if irq >= 0
+ * @from: Start the search from this irq number
+ * @cnt: Number of consecutive irqs to allocate.
+ * @node: Preferred node on which the irq descriptor should be allocated
+ * @owner: Owning module (can be NULL)
+ *
+ * Returns the first irq number of the reserved range or an error code
+ */
+int __ref
+__irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node,
+ struct module *owner)
+{
+ int start = __irq_reserve_irqs(irq, from, cnt);
+ return start < 0 ? start : alloc_descs(start, cnt, node, owner);
+}
EXPORT_SYMBOL_GPL(__irq_alloc_descs);

/**
@@ -396,20 +411,8 @@ EXPORT_SYMBOL_GPL(__irq_alloc_descs);
*/
int irq_reserve_irqs(unsigned int from, unsigned int cnt)
{
- unsigned int start;
- int ret = 0;
-
- if (!cnt || (from + cnt) > nr_irqs)
- return -EINVAL;
-
- mutex_lock(&sparse_irq_lock);
- start = bitmap_find_next_zero_area(allocated_irqs, nr_irqs, from, cnt, 0);
- if (start == from)
- bitmap_set(allocated_irqs, start, cnt);
- else
- ret = -EEXIST;
- mutex_unlock(&sparse_irq_lock);
- return ret;
+ int start = __irq_reserve_irqs(from, from, cnt);
+ return start < 0 ? start : 0;
}

/**
--
1.7.5.4

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