Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
relay: remove unused relay_late_setup_files
The last use of relay_late_setup_files() was removed in 2018 by commit
2b47733045aa ("drm/i915/guc: Merge log relay file and channel creation")
Remove it and the helper it used.
relay_late_setup_files() was used for eventually registering 'buffer only'
channels. With it gone, delete the docs that explain how to do that.
Which suggests it should be possible to lose the 'has_base_filename'
flags.
(Are there any other uses??)
Link: https://lkml.kernel.org/r/20250418234932.490863-1-linux@treblig.org
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andriy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
authored by
Dr. David Alan Gilbert
and committed by
Andrew Morton
2a1c6158
ba8182d4
+1
-123
-10
Documentation/filesystems/relay.rst
-10
Documentation/filesystems/relay.rst
···
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(including in create_buf_file()) via chan->private_data or
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buf->chan->private_data.
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-
Buffer-only channels
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-
--------------------
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-
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These channels have no files associated and can be created with
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relay_open(NULL, NULL, ...). Such channels are useful in scenarios such
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as when doing early tracing in the kernel, before the VFS is up. In these
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-
cases, one may open a buffer-only channel and then call
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relay_late_setup_files() when the kernel is ready to handle files,
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to expose the buffered data to the userspace.
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-
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Channel 'modes'
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---------------
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-3
include/linux/relay.h
-3
include/linux/relay.h
···
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size_t n_subbufs,
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const struct rchan_callbacks *cb,
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void *private_data);
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extern int relay_late_setup_files(struct rchan *chan,
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const char *base_filename,
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struct dentry *parent);
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extern void relay_close(struct rchan *chan);
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extern void relay_flush(struct rchan *chan);
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extern void relay_subbufs_consumed(struct rchan *chan,
+1
-110
kernel/relay.c
+1
-110
kernel/relay.c
···
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/**
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* relay_open - create a new relay channel
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-
* @base_filename: base name of files to create, %NULL for buffering only
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+
* @base_filename: base name of files to create
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* @parent: dentry of parent directory, %NULL for root directory or buffer
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* @subbuf_size: size of sub-buffers
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* @n_subbufs: number of sub-buffers
···
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* attributes specified. The created channel buffer files
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* will be named base_filename0...base_filenameN-1. File
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* permissions will be %S_IRUSR.
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*
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* If opening a buffer (@parent = NULL) that you later wish to register
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* in a filesystem, call relay_late_setup_files() once the @parent dentry
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* is available.
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*/
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struct rchan *relay_open(const char *base_filename,
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struct dentry *parent,
···
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struct rchan_buf *buf;
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struct dentry *dentry;
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};
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-
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/* Called in atomic context. */
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static void __relay_set_buf_dentry(void *info)
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{
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struct rchan_percpu_buf_dispatcher *p = info;
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-
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relay_set_buf_dentry(p->buf, p->dentry);
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}
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-
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/**
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* relay_late_setup_files - triggers file creation
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* @chan: channel to operate on
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* @base_filename: base name of files to create
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* @parent: dentry of parent directory, %NULL for root directory
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*
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* Returns 0 if successful, non-zero otherwise.
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*
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* Use to setup files for a previously buffer-only channel created
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* by relay_open() with a NULL parent dentry.
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*
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* For example, this is useful for perfomring early tracing in kernel,
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* before VFS is up and then exposing the early results once the dentry
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* is available.
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*/
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int relay_late_setup_files(struct rchan *chan,
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const char *base_filename,
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struct dentry *parent)
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{
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int err = 0;
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unsigned int i, curr_cpu;
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unsigned long flags;
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struct dentry *dentry;
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struct rchan_buf *buf;
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struct rchan_percpu_buf_dispatcher disp;
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if (!chan || !base_filename)
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return -EINVAL;
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-
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strscpy(chan->base_filename, base_filename, NAME_MAX);
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-
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mutex_lock(&relay_channels_mutex);
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/* Is chan already set up? */
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if (unlikely(chan->has_base_filename)) {
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mutex_unlock(&relay_channels_mutex);
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return -EEXIST;
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}
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chan->has_base_filename = 1;
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chan->parent = parent;
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if (chan->is_global) {
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err = -EINVAL;
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buf = *per_cpu_ptr(chan->buf, 0);
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if (!WARN_ON_ONCE(!buf)) {
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dentry = relay_create_buf_file(chan, buf, 0);
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if (dentry && !WARN_ON_ONCE(!chan->is_global)) {
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relay_set_buf_dentry(buf, dentry);
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err = 0;
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}
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}
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mutex_unlock(&relay_channels_mutex);
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return err;
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}
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curr_cpu = get_cpu();
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/*
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* The CPU hotplug notifier ran before us and created buffers with
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* no files associated. So it's safe to call relay_setup_buf_file()
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* on all currently online CPUs.
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*/
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for_each_online_cpu(i) {
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buf = *per_cpu_ptr(chan->buf, i);
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if (unlikely(!buf)) {
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WARN_ONCE(1, KERN_ERR "CPU has no buffer!\n");
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err = -EINVAL;
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break;
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}
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dentry = relay_create_buf_file(chan, buf, i);
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if (unlikely(!dentry)) {
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err = -EINVAL;
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break;
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}
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if (curr_cpu == i) {
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local_irq_save(flags);
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relay_set_buf_dentry(buf, dentry);
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local_irq_restore(flags);
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} else {
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disp.buf = buf;
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disp.dentry = dentry;
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smp_mb();
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/* relay_channels_mutex must be held, so wait. */
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err = smp_call_function_single(i,
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__relay_set_buf_dentry,
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&disp, 1);
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}
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if (unlikely(err))
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break;
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}
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put_cpu();
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mutex_unlock(&relay_channels_mutex);
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-
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return err;
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}
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EXPORT_SYMBOL_GPL(relay_late_setup_files);
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/**
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* relay_switch_subbuf - switch to a new sub-buffer