diff options
| -rw-r--r-- | Documentation/filesystems/relay.rst | 10 | ||||
| -rw-r--r-- | include/linux/relay.h | 3 | ||||
| -rw-r--r-- | kernel/relay.c | 111 |
3 files changed, 1 insertions, 123 deletions
diff --git a/Documentation/filesystems/relay.rst b/Documentation/filesystems/relay.rst index 04ad083cfe62..292ba8492aeb 100644 --- a/Documentation/filesystems/relay.rst +++ b/Documentation/filesystems/relay.rst @@ -301,16 +301,6 @@ user-defined data with a channel, and is immediately available (including in create_buf_file()) via chan->private_data or buf->chan->private_data. -Buffer-only channels --------------------- - -These channels have no files associated and can be created with -relay_open(NULL, NULL, ...). Such channels are useful in scenarios such -as when doing early tracing in the kernel, before the VFS is up. In these -cases, one may open a buffer-only channel and then call -relay_late_setup_files() when the kernel is ready to handle files, -to expose the buffered data to the userspace. - Channel 'modes' --------------- diff --git a/include/linux/relay.h b/include/linux/relay.h index 72b876dd5cb8..b3224111d074 100644 --- a/include/linux/relay.h +++ b/include/linux/relay.h @@ -159,9 +159,6 @@ struct rchan *relay_open(const char *base_filename, size_t n_subbufs, const struct rchan_callbacks *cb, void *private_data); -extern int relay_late_setup_files(struct rchan *chan, - const char *base_filename, - struct dentry *parent); extern void relay_close(struct rchan *chan); extern void relay_flush(struct rchan *chan); extern void relay_subbufs_consumed(struct rchan *chan, diff --git a/kernel/relay.c b/kernel/relay.c index 5ac7e711e4b6..c0c93a04d4ce 100644 --- a/kernel/relay.c +++ b/kernel/relay.c @@ -452,7 +452,7 @@ int relay_prepare_cpu(unsigned int cpu) /** * relay_open - create a new relay channel - * @base_filename: base name of files to create, %NULL for buffering only + * @base_filename: base name of files to create * @parent: dentry of parent directory, %NULL for root directory or buffer * @subbuf_size: size of sub-buffers * @n_subbufs: number of sub-buffers @@ -465,10 +465,6 @@ int relay_prepare_cpu(unsigned int cpu) * attributes specified. The created channel buffer files * will be named base_filename0...base_filenameN-1. File * permissions will be %S_IRUSR. - * - * If opening a buffer (@parent = NULL) that you later wish to register - * in a filesystem, call relay_late_setup_files() once the @parent dentry - * is available. */ struct rchan *relay_open(const char *base_filename, struct dentry *parent, @@ -540,111 +536,6 @@ struct rchan_percpu_buf_dispatcher { struct dentry *dentry; }; -/* Called in atomic context. */ -static void __relay_set_buf_dentry(void *info) -{ - struct rchan_percpu_buf_dispatcher *p = info; - - relay_set_buf_dentry(p->buf, p->dentry); -} - -/** - * relay_late_setup_files - triggers file creation - * @chan: channel to operate on - * @base_filename: base name of files to create - * @parent: dentry of parent directory, %NULL for root directory - * - * Returns 0 if successful, non-zero otherwise. - * - * Use to setup files for a previously buffer-only channel created - * by relay_open() with a NULL parent dentry. - * - * For example, this is useful for perfomring early tracing in kernel, - * before VFS is up and then exposing the early results once the dentry - * is available. - */ -int relay_late_setup_files(struct rchan *chan, - const char *base_filename, - struct dentry *parent) -{ - int err = 0; - unsigned int i, curr_cpu; - unsigned long flags; - struct dentry *dentry; - struct rchan_buf *buf; - struct rchan_percpu_buf_dispatcher disp; - - if (!chan || !base_filename) - return -EINVAL; - - strscpy(chan->base_filename, base_filename, NAME_MAX); - - mutex_lock(&relay_channels_mutex); - /* Is chan already set up? */ - if (unlikely(chan->has_base_filename)) { - mutex_unlock(&relay_channels_mutex); - return -EEXIST; - } - chan->has_base_filename = 1; - chan->parent = parent; - - if (chan->is_global) { - err = -EINVAL; - buf = *per_cpu_ptr(chan->buf, 0); - if (!WARN_ON_ONCE(!buf)) { - dentry = relay_create_buf_file(chan, buf, 0); - if (dentry && !WARN_ON_ONCE(!chan->is_global)) { - relay_set_buf_dentry(buf, dentry); - err = 0; - } - } - mutex_unlock(&relay_channels_mutex); - return err; - } - - curr_cpu = get_cpu(); - /* - * The CPU hotplug notifier ran before us and created buffers with - * no files associated. So it's safe to call relay_setup_buf_file() - * on all currently online CPUs. - */ - for_each_online_cpu(i) { - buf = *per_cpu_ptr(chan->buf, i); - if (unlikely(!buf)) { - WARN_ONCE(1, KERN_ERR "CPU has no buffer!\n"); - err = -EINVAL; - break; - } - - dentry = relay_create_buf_file(chan, buf, i); - if (unlikely(!dentry)) { - err = -EINVAL; - break; - } - - if (curr_cpu == i) { - local_irq_save(flags); - relay_set_buf_dentry(buf, dentry); - local_irq_restore(flags); - } else { - disp.buf = buf; - disp.dentry = dentry; - smp_mb(); - /* relay_channels_mutex must be held, so wait. */ - err = smp_call_function_single(i, - __relay_set_buf_dentry, - &disp, 1); - } - if (unlikely(err)) - break; - } - put_cpu(); - mutex_unlock(&relay_channels_mutex); - - return err; -} -EXPORT_SYMBOL_GPL(relay_late_setup_files); - /** * relay_switch_subbuf - switch to a new sub-buffer * @buf: channel buffer |