genirq: Support per-IRQ thread disabling.

This adds support for disabling threading on a per-IRQ basis via the IRQ
status instead of the IRQ flow, which is necessary for interrupts that
don't follow the natural IRQ flow channels, such as those that are
virtually created.

The new APIs added are simply:

	irq_set_thread()
	irq_set_nothread()

which follow the rest of the IRQ status routines.

Chained handlers also have IRQ_NOTHREAD set on them automatically, making
the lack of threading explicit rather than implicit. Subsequently, the
nothread flag can be viewed through the standard genirq debugging
facilities.

[ tglx: Fixed cleanup fallout ]

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Link: http://lkml.kernel.org/r/%3C20110406210135.GF18426%40linux-sh.org%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/include/linux/irq.h b/include/linux/irq.h
index a71dd18639fb2b6df331ae81c63ca8d88fe9866c..39c23786c1db02b90f75686f9aab1f0ed00219f7 100644 (file)
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -59,6 +59,7 @@ typedef       void (*irq_preflow_handler_t)(struct irq_data *data);
  * IRQ_NOPROBE                 - Interrupt cannot be probed by autoprobing
  * IRQ_NOREQUEST               - Interrupt cannot be requested via
  *                               request_irq()
+ * IRQ_NOTHREAD                        - Interrupt cannot be threaded
  * IRQ_NOAUTOEN                        - Interrupt is not automatically enabled in
  *                               request/setup_irq()
  * IRQ_NO_BALANCING            - Interrupt cannot be balanced (affinity set)
@@ -85,6 +86,7 @@ enum {
        IRQ_NO_BALANCING        = (1 << 13),
        IRQ_MOVE_PCNTXT         = (1 << 14),
        IRQ_NESTED_THREAD       = (1 << 15),
+       IRQ_NOTHREAD            = (1 << 16),
 };
 
 #define IRQF_MODIFY_MASK       \
@@ -422,7 +424,7 @@ irq_set_handler(unsigned int irq, irq_flow_handler_t handle)
 /*
  * Set a highlevel chained flow handler for a given IRQ.
  * (a chained handler is automatically enabled and set to
- *  IRQ_NOREQUEST and IRQ_NOPROBE)
+ *  IRQ_NOREQUEST, IRQ_NOPROBE, and IRQ_NOTHREAD)
  */
 static inline void
 irq_set_chained_handler(unsigned int irq, irq_flow_handler_t handle)
@@ -452,6 +454,16 @@ static inline void irq_set_probe(unsigned int irq)
        irq_modify_status(irq, IRQ_NOPROBE, 0);
 }
 
+static inline void irq_set_nothread(unsigned int irq)
+{
+       irq_modify_status(irq, 0, IRQ_NOTHREAD);
+}
+
+static inline void irq_set_thread(unsigned int irq)
+{
+       irq_modify_status(irq, IRQ_NOTHREAD, 0);
+}
+
 static inline void irq_set_nested_thread(unsigned int irq, bool nest)
 {
        if (nest)

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 4af1e2b244cb258f24ed7644b18965ac9e65bc82..52d856d513ffb5bbc83b9a2b440a5a0c9b3339de 100644 (file)
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -573,6 +573,7 @@ __irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
        if (handle != handle_bad_irq && is_chained) {
                irq_settings_set_noprobe(desc);
                irq_settings_set_norequest(desc);
+               irq_settings_set_nothread(desc);
                irq_startup(desc);
        }
 out:

diff --git a/kernel/irq/debug.h b/kernel/irq/debug.h
index 306cba37e9a57280b869b3317852efe48b34e78f..97a8bfadc88a0cec4192bd457e18a54aca159cf0 100644 (file)
--- a/kernel/irq/debug.h
+++ b/kernel/irq/debug.h
@@ -27,6 +27,7 @@ static inline void print_irq_desc(unsigned int irq, struct irq_desc *desc)
        P(IRQ_PER_CPU);
        P(IRQ_NOPROBE);
        P(IRQ_NOREQUEST);
+       P(IRQ_NOTHREAD);
        P(IRQ_NOAUTOEN);
 
        PS(IRQS_AUTODETECT);

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 07c1611f38992ac98e5e8bb716d4d41f01290ea4..f7ce0021e1c48eb02e2eb6531265ac84bfc24d96 100644 (file)
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -900,7 +900,8 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
                 */
                new->handler = irq_nested_primary_handler;
        } else {
-               irq_setup_forced_threading(new);
+               if (irq_settings_can_thread(desc))
+                       irq_setup_forced_threading(new);
        }
 
        /*

diff --git a/kernel/irq/settings.h b/kernel/irq/settings.h
index 0d91730b6330b9b59594fd2486d5a493627d7fb3..f1667833d444496d862a3bfdd87ead8d2d2fece2 100644 (file)
--- a/kernel/irq/settings.h
+++ b/kernel/irq/settings.h
@@ -8,6 +8,7 @@ enum {
        _IRQ_LEVEL              = IRQ_LEVEL,
        _IRQ_NOPROBE            = IRQ_NOPROBE,
        _IRQ_NOREQUEST          = IRQ_NOREQUEST,
+       _IRQ_NOTHREAD           = IRQ_NOTHREAD,
        _IRQ_NOAUTOEN           = IRQ_NOAUTOEN,
        _IRQ_MOVE_PCNTXT        = IRQ_MOVE_PCNTXT,
        _IRQ_NO_BALANCING       = IRQ_NO_BALANCING,
@@ -20,6 +21,7 @@ enum {
 #define IRQ_LEVEL              GOT_YOU_MORON
 #define IRQ_NOPROBE            GOT_YOU_MORON
 #define IRQ_NOREQUEST          GOT_YOU_MORON
+#define IRQ_NOTHREAD           GOT_YOU_MORON
 #define IRQ_NOAUTOEN           GOT_YOU_MORON
 #define IRQ_NESTED_THREAD      GOT_YOU_MORON
 #undef IRQF_MODIFY_MASK
@@ -94,6 +96,21 @@ static inline void irq_settings_set_norequest(struct irq_desc *desc)
        desc->status_use_accessors |= _IRQ_NOREQUEST;
 }
 
+static inline bool irq_settings_can_thread(struct irq_desc *desc)
+{
+       return !(desc->status_use_accessors & _IRQ_NOTHREAD);
+}
+
+static inline void irq_settings_clr_nothread(struct irq_desc *desc)
+{
+       desc->status_use_accessors &= ~_IRQ_NOTHREAD;
+}
+
+static inline void irq_settings_set_nothread(struct irq_desc *desc)
+{
+       desc->status_use_accessors |= _IRQ_NOTHREAD;
+}
+
 static inline bool irq_settings_can_probe(struct irq_desc *desc)
 {
        return !(desc->status_use_accessors & _IRQ_NOPROBE);