Inline implementation of task_prio()

The task_prio() function has been implemented as "return p->prio -
MAX_RT_PRIO;" since at least kernel v3.0, so inline it into
lttng-modules rather than using kallsyms to call the kernel
implementation.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I7dd482a2da72a005c16b3e5864767b47d7bc3fd3

diff --git a/include/lttng/events-internal.h b/include/lttng/events-internal.h
index 181b7b4552305456c16eb8662e76bdbf4dff0a7c..a727230ffffb8c21320b04b502e98ff4755987d1 100644 (file)
--- a/include/lttng/events-internal.h
+++ b/include/lttng/events-internal.h
@@ -649,7 +649,6 @@ int lttng_add_pid_to_ctx(struct lttng_kernel_ctx **ctx);
 int lttng_add_cpu_id_to_ctx(struct lttng_kernel_ctx **ctx);
 int lttng_add_procname_to_ctx(struct lttng_kernel_ctx **ctx);
 int lttng_add_prio_to_ctx(struct lttng_kernel_ctx **ctx);
-int wrapper_task_prio_init(void);
 int lttng_add_nice_to_ctx(struct lttng_kernel_ctx **ctx);
 int lttng_add_vpid_to_ctx(struct lttng_kernel_ctx **ctx);
 int lttng_add_tid_to_ctx(struct lttng_kernel_ctx **ctx);

diff --git a/src/lttng-context-prio.c b/src/lttng-context-prio.c
index aac10a6399ac8618a42e23c299edd8d41a0c7ee7..cbe9480030756ec1ba34bd0441626243f417f840 100644 (file)
--- a/src/lttng-context-prio.c
+++ b/src/lttng-context-prio.c
@@ -14,34 +14,16 @@
 #include <lttng/events-internal.h>
 #include <ringbuffer/frontend_types.h>
 #include <wrapper/vmalloc.h>
-#include <wrapper/kallsyms.h>
 #include <lttng/tracer.h>
 
-static
-int (*wrapper_task_prio_sym)(struct task_struct *t);
-
-int wrapper_task_prio_init(void)
-{
-       wrapper_task_prio_sym = (void *) kallsyms_lookup_funcptr("task_prio");
-       if (!wrapper_task_prio_sym) {
-               printk(KERN_WARNING "LTTng: task_prio symbol lookup failed.\n");
-               return -EINVAL;
-       }
-       return 0;
-}
-EXPORT_SYMBOL_GPL(wrapper_task_prio_init);
-
 /*
- * Canary function to check for 'task_prio()' at compile time.
- *
- * From 'include/linux/sched.h':
- *
- *   extern int task_prio(const struct task_struct *p);
+ * task_prio() has been implemented as p->prio - MAX_RT_PRIO since at
+ * least kernel v3.0.
  */
-__attribute__((unused)) static
-int __canary__task_prio(const struct task_struct *p)
+static
+int wrapper_task_prio(struct task_struct *p)
 {
-       return task_prio(p);
+       return p->prio - MAX_RT_PRIO;
 }
 
 static
@@ -61,7 +43,7 @@ void prio_record(void *priv, struct lttng_kernel_probe_ctx *probe_ctx,
 {
        int prio;
 
-       prio = wrapper_task_prio_sym(current);
+       prio = wrapper_task_prio(current);
        chan->ops->event_write(ctx, &prio, sizeof(prio), lttng_alignof(prio));
 }
 
@@ -70,7 +52,7 @@ void prio_get_value(void *priv,
                struct lttng_kernel_probe_ctx *lttng_probe_ctx,
                struct lttng_ctx_value *value)
 {
-       value->u.s64 = wrapper_task_prio_sym(current);
+       value->u.s64 = wrapper_task_prio(current);
 }
 
 static const struct lttng_kernel_ctx_field *ctx_field = lttng_kernel_static_ctx_field(

diff --git a/src/lttng-events.c b/src/lttng-events.c
index 08884410f20971781bc0305d1e63f92a86578620..a0bd232228c8dd6a3120134bce7cd16d2c5db33e 100644 (file)
--- a/src/lttng-events.c
+++ b/src/lttng-events.c
@@ -4148,9 +4148,6 @@ static int __init lttng_events_init(void)
        int ret;
 
        ret = wrapper_get_pfnblock_flags_mask_init();
-       if (ret)
-               return ret;
-       ret = wrapper_task_prio_init();
        if (ret)
                return ret;
        ret = lttng_probes_init();