From 3b8249e759c701c4a82f99d957be651a7657bf6f Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 7 Feb 2011 16:02:20 +0100 Subject: [PATCH] genirq: Do not copy affinity before set While rumaging through arch code I found that there are a few workarounds which deal with the fact that the initial affinity setting from request_irq() copies the mask into irq_data->affinity before the chip code is called. In the normal path we unconditionally copy the mask when the chip code returns 0. Copy after the code is called and add a return code IRQ_SET_MASK_OK_NOCOPY for the chip functions, which prevents the copy. That way we see the real mask when the chip function decided to truncate it further as some arches do. IRQ_SET_MASK_OK is 0, which is the current behaviour. Signed-off-by: Thomas Gleixner --- include/linux/irq.h | 11 +++++++++++ kernel/irq/internals.h | 2 +- kernel/irq/manage.c | 47 ++++++++++++++++++++++++++++++++++------------- kernel/irq/proc.c | 2 +- 4 files changed, 47 insertions(+), 15 deletions(-) diff --git a/include/linux/irq.h b/include/linux/irq.h index e9f847d..f5e9003 100644 --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -85,6 +85,17 @@ typedef void (*irq_flow_handler_t)(unsigned int irq, # define IRQ_NO_BALANCING_MASK IRQ_NO_BALANCING #endif +/* + * Return value for chip->irq_set_affinity() + * + * IRQ_SET_MASK_OK - OK, core updates irq_data.affinity + * IRQ_SET_MASK_NOCPY - OK, chip did update irq_data.affinity + */ +enum { + IRQ_SET_MASK_OK = 0, + IRQ_SET_MASK_OK_NOCOPY, +}; + struct msi_desc; /** diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h index 99c3bc8..b5bfa24 100644 --- a/kernel/irq/internals.h +++ b/kernel/irq/internals.h @@ -43,7 +43,7 @@ static inline void unregister_handler_proc(unsigned int irq, struct irqaction *action) { } #endif -extern int irq_select_affinity_usr(unsigned int irq); +extern int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask); extern void irq_set_thread_affinity(struct irq_desc *desc); diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index ade65bf..dc95d53 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -148,9 +148,12 @@ int irq_set_affinity(unsigned int irq, const struct cpumask *mask) if (irq_can_move_pcntxt(desc)) { ret = chip->irq_set_affinity(&desc->irq_data, mask, false); - if (!ret) { + switch (ret) { + case IRQ_SET_MASK_OK: cpumask_copy(desc->irq_data.affinity, mask); + case IRQ_SET_MASK_OK_NOCOPY: irq_set_thread_affinity(desc); + ret = 0; } } else { desc->status |= IRQ_MOVE_PENDING; @@ -254,9 +257,12 @@ EXPORT_SYMBOL_GPL(irq_set_affinity_notifier); /* * Generic version of the affinity autoselector. */ -static int setup_affinity(unsigned int irq, struct irq_desc *desc) +static int +setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask) { + struct irq_chip *chip = get_irq_desc_chip(desc); struct cpumask *set = irq_default_affinity; + int ret; /* Excludes PER_CPU and NO_BALANCE interrupts */ if (!irq_can_set_affinity(irq)) @@ -273,13 +279,20 @@ static int setup_affinity(unsigned int irq, struct irq_desc *desc) else desc->status &= ~IRQ_AFFINITY_SET; } - cpumask_and(desc->irq_data.affinity, cpu_online_mask, set); - desc->irq_data.chip->irq_set_affinity(&desc->irq_data, desc->irq_data.affinity, false); + cpumask_and(mask, cpu_online_mask, set); + ret = chip->irq_set_affinity(&desc->irq_data, mask, false); + switch (ret) { + case IRQ_SET_MASK_OK: + cpumask_copy(desc->irq_data.affinity, mask); + case IRQ_SET_MASK_OK_NOCOPY: + irq_set_thread_affinity(desc); + } return 0; } #else -static inline int setup_affinity(unsigned int irq, struct irq_desc *d) +static inline int +setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask) { return irq_select_affinity(irq); } @@ -288,23 +301,23 @@ static inline int setup_affinity(unsigned int irq, struct irq_desc *d) /* * Called when affinity is set via /proc/irq */ -int irq_select_affinity_usr(unsigned int irq) +int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask) { struct irq_desc *desc = irq_to_desc(irq); unsigned long flags; int ret; raw_spin_lock_irqsave(&desc->lock, flags); - ret = setup_affinity(irq, desc); + ret = setup_affinity(irq, desc, mask); if (!ret) irq_set_thread_affinity(desc); raw_spin_unlock_irqrestore(&desc->lock, flags); - return ret; } #else -static inline int setup_affinity(unsigned int irq, struct irq_desc *desc) +static inline int +setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask) { return 0; } @@ -765,8 +778,8 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) struct irqaction *old, **old_ptr; const char *old_name = NULL; unsigned long flags; - int nested, shared = 0; - int ret; + int ret, nested, shared = 0; + cpumask_var_t mask; if (!desc) return -EINVAL; @@ -831,6 +844,11 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) new->thread = t; } + if (!alloc_cpumask_var(&mask, GFP_KERNEL)) { + ret = -ENOMEM; + goto out_thread; + } + /* * The following block of code has to be executed atomically */ @@ -876,7 +894,7 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) new->flags & IRQF_TRIGGER_MASK); if (ret) - goto out_thread; + goto out_mask; } else compat_irq_chip_set_default_handler(desc); #if defined(CONFIG_IRQ_PER_CPU) @@ -903,7 +921,7 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) desc->status |= IRQ_NO_BALANCING; /* Set default affinity mask once everything is setup */ - setup_affinity(irq, desc); + setup_affinity(irq, desc, mask); } else if ((new->flags & IRQF_TRIGGER_MASK) && (new->flags & IRQF_TRIGGER_MASK) @@ -956,6 +974,9 @@ mismatch: #endif ret = -EBUSY; +out_mask: + free_cpumask_var(mask); + out_thread: raw_spin_unlock_irqrestore(&desc->lock, flags); if (new->thread) { diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c index 6c8a2a9..a46bd76 100644 --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c @@ -89,7 +89,7 @@ static ssize_t irq_affinity_proc_write(struct file *file, if (!cpumask_intersects(new_value, cpu_online_mask)) { /* Special case for empty set - allow the architecture code to set default SMP affinity. */ - err = irq_select_affinity_usr(irq) ? -EINVAL : count; + err = irq_select_affinity_usr(irq, new_value) ? -EINVAL : count; } else { irq_set_affinity(irq, new_value); err = count; -- 2.7.4