irq: Add irq_set_chained_handler_and_data()

Driver authors seem to get the ordering of irq_set_chained_handler()
and irq_set_handler_data() wrong - ordering the former before the
latter.  This opens a race window where, if there is an interrupt
pending, the handler will be called between these two calls,
potentially resulting in an oops.

Provide a single interface to set both of these together, especially
as that's commonly what is required.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Hans Ulli Kroll <ulli.kroll@googlemail.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/E1Z4yzs-0002Rw-4B@rmk-PC.arm.linux.org.uk
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/include/linux/irq.h b/include/linux/irq.h
index de3213d271ffd50fc5839c18407ae8c184053b0d..42861d28fc2a89bccabe24ef9cd4045fe59538c8 100644 (file)
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -525,6 +525,15 @@ irq_set_chained_handler(unsigned int irq, irq_flow_handler_t handle)
        __irq_set_handler(irq, handle, 1, NULL);
 }
 
+/*
+ * Set a highlevel chained flow handler and its data for a given IRQ.
+ * (a chained handler is automatically enabled and set to
+ *  IRQ_NOREQUEST, IRQ_NOPROBE, and IRQ_NOTHREAD)
+ */
+void
+irq_set_chained_handler_and_data(unsigned int irq, irq_flow_handler_t handle,
+                                void *data);
+
 void irq_modify_status(unsigned int irq, unsigned long clr, unsigned long set);
 
 static inline void irq_set_status_flags(unsigned int irq, unsigned long set)

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 330fc797e632cb68e75d75bf59ea61d7134be320..27f4332c7f84ea8b3d7ec8bb3466a64f225a8487 100644 (file)
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -719,15 +719,9 @@ void handle_percpu_devid_irq(unsigned int irq, struct irq_desc *desc)
 }
 
 void
-__irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
-                 const char *name)
+__irq_do_set_handler(struct irq_desc *desc, irq_flow_handler_t handle,
+                    int is_chained, const char *name)
 {
-       unsigned long flags;
-       struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, 0);
-
-       if (!desc)
-               return;
-
        if (!handle) {
                handle = handle_bad_irq;
        } else {
@@ -749,13 +743,13 @@ __irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
                         * right away.
                         */
                        if (WARN_ON(is_chained))
-                               goto out;
+                               return;
                        /* Try the parent */
                        irq_data = irq_data->parent_data;
                }
 #endif
                if (WARN_ON(!irq_data || irq_data->chip == &no_irq_chip))
-                       goto out;
+                       return;
        }
 
        /* Uninstall? */
@@ -774,11 +768,40 @@ __irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
                irq_settings_set_nothread(desc);
                irq_startup(desc, true);
        }
-out:
+}
+
+void
+__irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
+                 const char *name)
+{
+       unsigned long flags;
+       struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, 0);
+
+       if (!desc)
+               return;
+
+       __irq_do_set_handler(desc, handle, is_chained, name);
        irq_put_desc_busunlock(desc, flags);
 }
 EXPORT_SYMBOL_GPL(__irq_set_handler);
 
+void
+irq_set_chained_handler_and_data(unsigned int irq, irq_flow_handler_t handle,
+                                void *data)
+{
+       unsigned long flags;
+       struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, 0);
+
+       if (!desc)
+               return;
+
+       __irq_do_set_handler(desc, handle, 1, NULL);
+       desc->irq_data.handler_data = data;
+
+       irq_put_desc_busunlock(desc, flags);
+}
+EXPORT_SYMBOL_GPL(irq_set_chained_handler_and_data);
+
 void
 irq_set_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
                              irq_flow_handler_t handle, const char *name)