diff options
| author | Yinghai Lu <yinghai@kernel.org> | 2011-02-19 11:07:37 -0800 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2011-02-21 21:20:00 +0100 |
| commit | ed4dea6e0e33a3e58d8b77b775a8f0e433e7a005 (patch) | |
| tree | 99f3168f5307545e6107603431e877b5369f767f /kernel | |
| parent | a61d825808a0ce9935afebc225dcd602d5339e14 (diff) | |
genirq: Use IRQ_BITMAP_BITS as search size in irq_alloc_descs()
The runtime expansion of nr_irqs does not take into account that
bitmap_find_next_zero_area() returns "start" + size in case the search
for an matching zero area fails. That results in a start value which
can be completely off and is not covered by the following
expand_nr_irqs() and possibly outside of the absolute limit. But we
use it without further checking.
Use IRQ_BITMAP_BITS as the limit for the bitmap search and expand
nr_irqs when the start bit is beyond nr_irqs. So start is always
pointing to the correct area in the bitmap. nr_irqs is just the limit
for irq enumerations, not the real limit for the irq space.
[ tglx: Let irq_expand_nr_irqs() take the new upper end so we do not
expand nr_irqs more than necessary. Made changelog readable ]
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4D6014F9.8040605@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/irq/irqdesc.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c index 394ab6a6c62..dbccc799407 100644 --- a/kernel/irq/irqdesc.c +++ b/kernel/irq/irqdesc.c @@ -207,11 +207,11 @@ struct irq_desc * __ref irq_to_desc_alloc_node(unsigned int irq, int node) return NULL; } -static int irq_expand_nr_irqs(unsigned int cnt) +static int irq_expand_nr_irqs(unsigned int nr) { - if (nr_irqs + cnt > IRQ_BITMAP_BITS) + if (nr > IRQ_BITMAP_BITS) return -ENOMEM; - nr_irqs += cnt; + nr_irqs = nr; return 0; } @@ -298,7 +298,7 @@ static inline int alloc_descs(unsigned int start, unsigned int cnt, int node) return start; } -static int irq_expand_nr_irqs(unsigned int cnt) +static int irq_expand_nr_irqs(unsigned int nr) { return -ENOMEM; } @@ -346,13 +346,14 @@ irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node) mutex_lock(&sparse_irq_lock); - start = bitmap_find_next_zero_area(allocated_irqs, nr_irqs, from, cnt, 0); + start = bitmap_find_next_zero_area(allocated_irqs, IRQ_BITMAP_BITS, + from, cnt, 0); ret = -EEXIST; if (irq >=0 && start != irq) goto err; - if (start >= nr_irqs) { - ret = irq_expand_nr_irqs(cnt); + if (start + cnt > nr_irqs) { + ret = irq_expand_nr_irqs(start + cnt); if (ret) goto err; } |