lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

ftrace: add trace pipe header pluggin

Browse Source 
This patch adds a method for open_pipe and open_read to the pluggins
so that they can add a header to the trace pipe call.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Steven Rostedt
2008-05-12 21:21:01 +02:00
committed by Thomas Gleixner
parent 53d0aa7730
commit 107bad8bef
2 changed files with 36 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

38
kernel/trace/trace.c
View File

@@ -2307,11 +2307,15 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
if (!iter)
return -ENOMEM;
mutex_lock(&trace_types_lock);
iter->tr = &global_trace;
iter->trace = current_trace;
filp->private_data = iter;
if (iter->trace->pipe_open)
iter->trace->pipe_open(iter);
mutex_unlock(&trace_types_lock);
return 0;
}
@@ -2380,13 +2384,24 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
return cnt;
}
mutex_lock(&trace_types_lock);
if (iter->trace->read) {
ret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
if (ret) {
read = ret;
goto out;
}
}
trace_seq_reset(&iter->seq);
start = 0;
while (trace_empty(iter)) {
if ((filp->f_flags & O_NONBLOCK))
return -EAGAIN;
if ((filp->f_flags & O_NONBLOCK)) {
read = -EAGAIN;
goto out;
}
/*
* This is a make-shift waitqueue. The reason we don't use
@@ -2400,16 +2415,22 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
set_current_state(TASK_INTERRUPTIBLE);
iter->tr->waiter = current;
mutex_unlock(&trace_types_lock);
/* sleep for one second, and try again. */
schedule_timeout(HZ);
mutex_lock(&trace_types_lock);
iter->tr->waiter = NULL;
if (signal_pending(current))
return -EINTR;
if (signal_pending(current)) {
read = -EINTR;
goto out;
}
if (iter->trace != current_trace)
return 0;
goto out;
/*
* We block until we read something and tracing is disabled.
@@ -2428,7 +2449,7 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
/* stop when tracing is finished */
if (trace_empty(iter))
return 0;
goto out;
if (cnt >= PAGE_SIZE)
cnt = PAGE_SIZE - 1;
@@ -2518,6 +2539,9 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
if (ret)
read = -EFAULT;
out:
mutex_unlock(&trace_types_lock);
return read;
}