hw-breakpoints: Drop callback and task parameters from modify helper

Drop the callback and task parameters from modify_user_hw_breakpoint().
For now we have no user that need to modify a breakpoint to the point
of changing its handler or its task context.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: "K. Prasad" <prasad@linux.vnet.ibm.com>

arch/x86/kernel/ptrace.c

@@ -618,7 +618,7 @@ ptrace_modify_breakpoint(struct perf_event *bp, int len, int type,
 	attr.bp_type = gen_type;
 	attr.disabled = disabled;
 
-	return modify_user_hw_breakpoint(bp, &attr, bp->callback, tsk);
+	return modify_user_hw_breakpoint(bp, &attr);
 }
 
 /*
@@ -740,7 +740,7 @@ static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
 
 		attr = bp->attr;
 		attr.bp_addr = addr;
-		bp = modify_user_hw_breakpoint(bp, &attr, bp->callback, tsk);
+		bp = modify_user_hw_breakpoint(bp, &attr);
 	}
 	/*
 	 * CHECKME: the previous code returned -EIO if the addr wasn't a

include/linux/hw_breakpoint.h

@@ -57,10 +57,7 @@ register_user_hw_breakpoint(struct perf_event_attr *attr,
 
 /* FIXME: only change from the attr, and don't unregister */
 extern struct perf_event *
-modify_user_hw_breakpoint(struct perf_event *bp,
-			  struct perf_event_attr *attr,
-			  perf_callback_t triggered,
-			  struct task_struct *tsk);
+modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr);
 
 /*
  * Kernel breakpoints are not associated with any particular thread.
@@ -97,9 +94,7 @@ register_user_hw_breakpoint(struct perf_event_attr *attr,
 			    struct task_struct *tsk)	{ return NULL; }
 static inline struct perf_event *
 modify_user_hw_breakpoint(struct perf_event *bp,
-			  struct perf_event_attr *attr,
-			  perf_callback_t triggered,
-			  struct task_struct *tsk)	{ return NULL; }
+			  struct perf_event_attr *attr)	{ return NULL; }
 static inline struct perf_event *
 register_wide_hw_breakpoint_cpu(struct perf_event_attr *attr,
 				perf_callback_t triggered,

kernel/hw_breakpoint.c

@@ -312,9 +312,7 @@ EXPORT_SYMBOL_GPL(register_user_hw_breakpoint);
  * @tsk: pointer to 'task_struct' of the process to which the address belongs
  */
 struct perf_event *
-modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr,
-			  perf_callback_t triggered,
-			  struct task_struct *tsk)
+modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr)
 {
 	/*
 	 * FIXME: do it without unregistering
@@ -323,7 +321,8 @@ modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr,
 	 */
 	unregister_hw_breakpoint(bp);
 
-	return perf_event_create_kernel_counter(attr, -1, tsk->pid, triggered);
+	return perf_event_create_kernel_counter(attr, -1, bp->ctx->task->pid,
+						bp->callback);
 }
 EXPORT_SYMBOL_GPL(modify_user_hw_breakpoint);