[Adeos-main] [PATCH] let ipipe_catch_event return old handler

[Jan Kiszka]

Hi,

this patch extends ipipe_catch_event() so that the previously registered
event handler is returned. The usage scenario are event listeners that
hook onto an existing listener for a specific domain, maybe filtering
events or simply overruling the original handler.

Note that this patch effectively removes the error detection from
ipipe_catch_event(), i.e. requests for event >= IPIPE_NR_EVENTS will be
silently ignored now. Regarding Xenomai as Ipipe user, this is a
non-issue as return codes are not checked there and only valid events
are passed.

Jan

Index: linux-2.6.16.1/include/linux/ipipe.h
===================================================================
--- linux-2.6.16.1.orig/include/linux/ipipe.h
+++ linux-2.6.16.1/include/linux/ipipe.h
@@ -125,9 +125,13 @@
 typedef void (*ipipe_irq_handler_t)(unsigned irq,
                                    void *cookie);
 
+#define IPIPE_SAME_HANDLER     ((ipipe_irq_handler_t)(-1))
+
 typedef int (*ipipe_irq_ackfn_t)(unsigned irq);
 
-#define IPIPE_SAME_HANDLER     ((ipipe_irq_handler_t)(-1))
+typedef int (*ipipe_event_handler_t)(unsigned event,
+                                    struct ipipe_domain *from,
+                                    void *data);
 
 struct ipipe_domain {
 
@@ -150,9 +154,7 @@
                void *cookie;
        } ____cacheline_aligned irqs[IPIPE_NR_IRQS];
 
-       int (*evhand[IPIPE_NR_EVENTS])(unsigned event,
-                                      struct ipipe_domain *from,
-                                      void *data); /* Event handlers. */
+       ipipe_event_handler_t evhand[IPIPE_NR_EVENTS]; /* Event handlers. */
        unsigned long long evself;      /* Self-monitored event bits. */
 
 #ifdef CONFIG_IPIPE_STATS
@@ -711,11 +713,9 @@
        clear_bit(IPIPE_SPRINTK_FLAG, &ipd->flags);
 }
 
-int ipipe_catch_event(struct ipipe_domain *ipd,
-                     unsigned event,
-                     int (*handler)(unsigned event,
-                                    struct ipipe_domain *ipd,
-                                    void *data));
+ipipe_event_handler_t ipipe_catch_event(struct ipipe_domain *ipd,
+                                       unsigned event,
+                                       ipipe_event_handler_t handler);
 
 cpumask_t ipipe_set_irq_affinity(unsigned irq,
                                 cpumask_t cpumask);
Index: linux-2.6.16.1/kernel/ipipe/generic.c
===================================================================
--- linux-2.6.16.1.orig/kernel/ipipe/generic.c
+++ linux-2.6.16.1/kernel/ipipe/generic.c
@@ -266,9 +266,9 @@
  * ipipe_catch_event() -- Interpose or remove an event handler for a
  * given domain.
  */
-int ipipe_catch_event(struct ipipe_domain *ipd,
-                     unsigned event,
-                     int (*handler)(unsigned event, struct ipipe_domain *ipd, 
void *data))
+ipipe_event_handler_t ipipe_catch_event(struct ipipe_domain *ipd,
+                                       unsigned event,
+                                       ipipe_event_handler_t handler)
 {
        int self = 0;
 
@@ -278,7 +278,7 @@
        }
 
        if (event >= IPIPE_NR_EVENTS)
-               return -EINVAL;
+               return NULL;
 
        if (!xchg(&ipd->evhand[event],handler)) {
                if (handler) {
@@ -301,7 +301,7 @@
                        ipd->evself |= (1LL << event);
        }
 
-       return 0;
+       return handler;
 }
 
 cpumask_t ipipe_set_irq_affinity (unsigned irq, cpumask_t cpumask)

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