mirror of https://gitee.com/openkylin/linux.git
tracing: Fix polling on trace_pipe_raw
The trace_pipe_raw never implemented polling and this was casing issues for several utilities. This is now implemented. Blocked reads still are on the TODO list. Reported-by: Mauro Carvalho Chehab <mchehab@redhat.com> Tested-by: Mauro Carvalho Chehab <mchehab@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Steven Rostedt
Steven Rostedt
parent
189e5784f6
commit
cc60cdc952
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@ -3555,10 +3555,8 @@ static int tracing_release_pipe(struct inode *inode, struct file *file)
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}
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static unsigned int
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tracing_poll_pipe(struct file *filp, poll_table *poll_table)
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trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table)
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{
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struct trace_iterator *iter = filp->private_data;
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if (trace_flags & TRACE_ITER_BLOCK) {
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/*
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* Always select as readable when in blocking mode
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@ -3567,6 +3565,7 @@ tracing_poll_pipe(struct file *filp, poll_table *poll_table)
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} else {
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if (!trace_empty(iter))
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return POLLIN | POLLRDNORM;
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trace_wakeup_needed = true;
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poll_wait(filp, &trace_wait, poll_table);
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if (!trace_empty(iter))
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return POLLIN | POLLRDNORM;
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@ -3575,6 +3574,14 @@ tracing_poll_pipe(struct file *filp, poll_table *poll_table)
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}
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}
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static unsigned int
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tracing_poll_pipe(struct file *filp, poll_table *poll_table)
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{
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struct trace_iterator *iter = filp->private_data;
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return trace_poll(iter, filp, poll_table);
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}
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/*
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* This is a make-shift waitqueue.
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* A tracer might use this callback on some rare cases:
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@ -4362,9 +4369,8 @@ static const struct file_operations snapshot_fops = {
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#endif /* CONFIG_TRACER_SNAPSHOT */
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struct ftrace_buffer_info {
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struct trace_array *tr;
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struct trace_iterator iter;
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void *spare;
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int cpu;
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unsigned int read;
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};
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@ -4381,22 +4387,32 @@ static int tracing_buffers_open(struct inode *inode, struct file *filp)
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if (!info)
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return -ENOMEM;
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info->tr = tr;
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info->cpu = tc->cpu;
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info->spare = NULL;
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info->iter.tr = tr;
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info->iter.cpu_file = tc->cpu;
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info->spare = NULL;
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/* Force reading ring buffer for first read */
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info->read = (unsigned int)-1;
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info->read = (unsigned int)-1;
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filp->private_data = info;
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return nonseekable_open(inode, filp);
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}
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static unsigned int
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tracing_buffers_poll(struct file *filp, poll_table *poll_table)
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{
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struct ftrace_buffer_info *info = filp->private_data;
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struct trace_iterator *iter = &info->iter;
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return trace_poll(iter, filp, poll_table);
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}
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static ssize_t
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tracing_buffers_read(struct file *filp, char __user *ubuf,
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size_t count, loff_t *ppos)
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{
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struct ftrace_buffer_info *info = filp->private_data;
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struct trace_iterator *iter = &info->iter;
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ssize_t ret;
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size_t size;
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@ -4404,7 +4420,7 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
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return 0;
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if (!info->spare)
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info->spare = ring_buffer_alloc_read_page(info->tr->buffer, info->cpu);
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info->spare = ring_buffer_alloc_read_page(iter->tr->buffer, iter->cpu_file);
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if (!info->spare)
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return -ENOMEM;
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@ -4412,12 +4428,12 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
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if (info->read < PAGE_SIZE)
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goto read;
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trace_access_lock(info->cpu);
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ret = ring_buffer_read_page(info->tr->buffer,
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trace_access_lock(iter->cpu_file);
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ret = ring_buffer_read_page(iter->tr->buffer,
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&info->spare,
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count,
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info->cpu, 0);
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trace_access_unlock(info->cpu);
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iter->cpu_file, 0);
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trace_access_unlock(iter->cpu_file);
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if (ret < 0)
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return 0;
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@ -4442,9 +4458,10 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
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static int tracing_buffers_release(struct inode *inode, struct file *file)
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{
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struct ftrace_buffer_info *info = file->private_data;
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struct trace_iterator *iter = &info->iter;
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if (info->spare)
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ring_buffer_free_read_page(info->tr->buffer, info->spare);
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ring_buffer_free_read_page(iter->tr->buffer, info->spare);
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kfree(info);
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return 0;
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@ -4511,6 +4528,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
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unsigned int flags)
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{
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struct ftrace_buffer_info *info = file->private_data;
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struct trace_iterator *iter = &info->iter;
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struct partial_page partial_def[PIPE_DEF_BUFFERS];
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struct page *pages_def[PIPE_DEF_BUFFERS];
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struct splice_pipe_desc spd = {
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@ -4541,8 +4559,9 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
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len &= PAGE_MASK;
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}
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trace_access_lock(info->cpu);
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entries = ring_buffer_entries_cpu(info->tr->buffer, info->cpu);
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again:
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trace_access_lock(iter->cpu_file);
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entries = ring_buffer_entries_cpu(iter->tr->buffer, iter->cpu_file);
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for (i = 0; i < pipe->buffers && len && entries; i++, len -= PAGE_SIZE) {
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struct page *page;
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@ -4553,15 +4572,15 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
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break;
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ref->ref = 1;
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ref->buffer = info->tr->buffer;
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ref->page = ring_buffer_alloc_read_page(ref->buffer, info->cpu);
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ref->buffer = iter->tr->buffer;
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ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
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if (!ref->page) {
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kfree(ref);
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break;
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}
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r = ring_buffer_read_page(ref->buffer, &ref->page,
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len, info->cpu, 1);
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len, iter->cpu_file, 1);
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if (r < 0) {
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ring_buffer_free_read_page(ref->buffer, ref->page);
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kfree(ref);
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@ -4585,20 +4604,24 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
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spd.nr_pages++;
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*ppos += PAGE_SIZE;
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entries = ring_buffer_entries_cpu(info->tr->buffer, info->cpu);
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entries = ring_buffer_entries_cpu(iter->tr->buffer, iter->cpu_file);
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}
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trace_access_unlock(info->cpu);
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trace_access_unlock(iter->cpu_file);
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spd.nr_pages = i;
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/* did we read anything? */
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if (!spd.nr_pages) {
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if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
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if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK)) {
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ret = -EAGAIN;
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else
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ret = 0;
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/* TODO: block */
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goto out;
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goto out;
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}
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default_wait_pipe(iter);
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if (signal_pending(current)) {
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ret = -EINTR;
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goto out;
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}
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goto again;
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}
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ret = splice_to_pipe(pipe, &spd);
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@ -4610,6 +4633,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
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static const struct file_operations tracing_buffers_fops = {
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.open = tracing_buffers_open,
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.read = tracing_buffers_read,
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.poll = tracing_buffers_poll,
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.release = tracing_buffers_release,
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.splice_read = tracing_buffers_splice_read,
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.llseek = no_llseek,
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