Messages in this thread Patch in this message | | | Subject | [PATCH 6/6] powerpc: use irq_alloc_desc() to manage irq allocations | From | Grant Likely <> | Date | Thu, 28 Apr 2011 14:02:14 -0600 |
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This patch drops the architecture specific code for managing irq assignments and uses core code instead.
*RFC*
This patch is *not* ready for merging. The locking is messed up where the irq_map is still used to find out if a mapping is already established, but irq_alloc_desc() is now called before the irq_map is updated which creates a race condition. I've not completely sorted out how to solve this yet. The solution may very well be to convert the irq_big_lock to a mutex (but I'm not sure if anything that sleeps calls the affected code), and hold the mutex over the entire operation.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca> --- arch/powerpc/kernel/irq.c | 51 ++++++++++++--------------------------------- 1 files changed, 14 insertions(+), 37 deletions(-)
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c index 0fb90ab..e4a6646 100644 --- a/arch/powerpc/kernel/irq.c +++ b/arch/powerpc/kernel/irq.c @@ -984,53 +984,29 @@ unsigned int irq_linear_revmap(struct irq_host *host, static unsigned int irq_alloc_virt(struct irq_host *host, unsigned int hint) { unsigned long flags; - unsigned int i, j, found = NO_IRQ; - int res; + int found; - raw_spin_lock_irqsave(&irq_big_lock, flags); - - /* Use hint for 1 interrupt if any */ - if (hint >= NUM_ISA_INTERRUPTS && - hint < irq_virq_count && irq_map[hint].host == NULL) { - found = hint; - goto hint_found; - } - - /* Look for a free virq in the allocatable (non-legacy) space */ - for (i = NUM_ISA_INTERRUPTS, j = 0; i < irq_virq_count; i++) { - if (irq_map[i].host == NULL) { - found = i; - break; - } - } - if (found == NO_IRQ) { - raw_spin_unlock_irqrestore(&irq_big_lock, flags); + /* + * Find an unused interrupt. First, attempt to allocate + * 'hint'. If that fails, then just allocate any free one. + */ + found = irq_alloc_desc_at(hint, 0); + if (found <= NO_IRQ) + found = irq_alloc_desc(0); + if (found <= NO_IRQ) { + pr_debug("irq: -> allocating desc failed\n"); return NO_IRQ; } - hint_found: + + raw_spin_lock_irqsave(&irq_big_lock, flags); irq_map[found].hwirq = host->inval_irq; smp_wmb(); irq_map[found].host = host; raw_spin_unlock_irqrestore(&irq_big_lock, flags); - res = irq_alloc_desc_at(found, 0); - if (res != found) { - pr_debug("irq: -> allocating desc failed\n"); - goto error_desc; - } - irq_clear_status_flags(found, IRQ_NOREQUEST); return found; - - error_desc: - raw_spin_lock_irqsave(&irq_big_lock, flags); - host = irq_map[found].host; - irq_map[found].hwirq = host->inval_irq; - smp_wmb(); - irq_map[found].host = NULL; - raw_spin_unlock_irqrestore(&irq_big_lock, flags); - return NO_IRQ; } /** @@ -1051,13 +1027,14 @@ static void irq_free_virt(unsigned int virq) return; } - irq_free_descs(virq, 1); raw_spin_lock_irqsave(&irq_big_lock, flags); host = irq_map[virq].host; irq_map[virq].hwirq = host->inval_irq; smp_wmb(); irq_map[virq].host = NULL; raw_spin_unlock_irqrestore(&irq_big_lock, flags); + + irq_free_descs(virq, 1); } int arch_early_irq_init(void)
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