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Commit ff98781b authored by Eduard - Gabriel Munteanu's avatar Eduard - Gabriel Munteanu Committed by Steven Rostedt
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tracing: Move pipe waiting code out of tracing_read_pipe(). 



This moves the pipe waiting code from tracing_read_pipe() into
tracing_wait_pipe(), which is useful to implement other fops, like
splice_read.

Signed-off-by: default avatarEduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
parent 3c56819b

kernel/trace/trace.c

+40 −29
Original line number Diff line number Diff line
@@ -2388,37 +2388,15 @@ tracing_poll_pipe(struct file *filp, poll_table *poll_table) 
	}

}



/*

 * Consumer reader.

 */

static ssize_t

tracing_read_pipe(struct file *filp, char __user *ubuf,

		  size_t cnt, loff_t *ppos)

/* Must be called with trace_types_lock mutex held. */

static int tracing_wait_pipe(struct file *filp)

{

	struct trace_iterator *iter = filp->private_data;

	ssize_t sret;



	/* return any leftover data */

	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);

	if (sret != -EBUSY)

		return sret;



	trace_seq_reset(&iter->seq);



	mutex_lock(&trace_types_lock);

	if (iter->trace->read) {

		sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);

		if (sret)

			goto out;

	}



waitagain:

	sret = 0;

	while (trace_empty(iter)) {



		if ((filp->f_flags & O_NONBLOCK)) {

			sret = -EAGAIN;

			goto out;

			return -EAGAIN;

		}



		/*
@@ -2443,12 +2421,11 @@ tracing_read_pipe(struct file *filp, char __user *ubuf, 
		iter->tr->waiter = NULL;



		if (signal_pending(current)) {

			sret = -EINTR;

			goto out;

			return -EINTR;

		}



		if (iter->trace != current_trace)

			goto out;

			return 0;



		/*

		 * We block until we read something and tracing is disabled.
@@ -2465,9 +2442,43 @@ tracing_read_pipe(struct file *filp, char __user *ubuf, 
		continue;

	}



	return 1;

}



/*

 * Consumer reader.

 */

static ssize_t

tracing_read_pipe(struct file *filp, char __user *ubuf,

		  size_t cnt, loff_t *ppos)

{

	struct trace_iterator *iter = filp->private_data;

	ssize_t sret;



	/* return any leftover data */

	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);

	if (sret != -EBUSY)

		return sret;



	trace_seq_reset(&iter->seq);



	mutex_lock(&trace_types_lock);

	if (iter->trace->read) {

		sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);

		if (sret)

			goto out;

	}



waitagain:

	sret = tracing_wait_pipe(filp);

	if (sret <= 0)

		goto out;



	/* stop when tracing is finished */

	if (trace_empty(iter))

	if (trace_empty(iter)) {

		sret = 0;

		goto out;

	}



	if (cnt >= PAGE_SIZE)

		cnt = PAGE_SIZE - 1;