diff options
Diffstat (limited to 'fs/relayfs/relay.c')
| -rw-r--r-- | fs/relayfs/relay.c | 482 |
1 files changed, 0 insertions, 482 deletions
diff --git a/fs/relayfs/relay.c b/fs/relayfs/relay.c deleted file mode 100644 index abf3ceaace491..0000000000000 --- a/fs/relayfs/relay.c +++ /dev/null @@ -1,482 +0,0 @@ -/* - * Public API and common code for RelayFS. - * - * See Documentation/filesystems/relayfs.txt for an overview of relayfs. - * - * Copyright (C) 2002-2005 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp - * Copyright (C) 1999-2005 - Karim Yaghmour (karim@opersys.com) - * - * This file is released under the GPL. - */ - -#include <linux/errno.h> -#include <linux/stddef.h> -#include <linux/slab.h> -#include <linux/module.h> -#include <linux/string.h> -#include <linux/relayfs_fs.h> -#include "relay.h" -#include "buffers.h" - -/** - * relay_buf_empty - boolean, is the channel buffer empty? - * @buf: channel buffer - * - * Returns 1 if the buffer is empty, 0 otherwise. - */ -int relay_buf_empty(struct rchan_buf *buf) -{ - return (buf->subbufs_produced - buf->subbufs_consumed) ? 0 : 1; -} - -/** - * relay_buf_full - boolean, is the channel buffer full? - * @buf: channel buffer - * - * Returns 1 if the buffer is full, 0 otherwise. - */ -int relay_buf_full(struct rchan_buf *buf) -{ - size_t ready = buf->subbufs_produced - buf->subbufs_consumed; - return (ready >= buf->chan->n_subbufs) ? 1 : 0; -} - -/* - * High-level relayfs kernel API and associated functions. - */ - -/* - * rchan_callback implementations defining default channel behavior. Used - * in place of corresponding NULL values in client callback struct. - */ - -/* - * subbuf_start() default callback. Does nothing. - */ -static int subbuf_start_default_callback (struct rchan_buf *buf, - void *subbuf, - void *prev_subbuf, - size_t prev_padding) -{ - if (relay_buf_full(buf)) - return 0; - - return 1; -} - -/* - * buf_mapped() default callback. Does nothing. - */ -static void buf_mapped_default_callback(struct rchan_buf *buf, - struct file *filp) -{ -} - -/* - * buf_unmapped() default callback. Does nothing. - */ -static void buf_unmapped_default_callback(struct rchan_buf *buf, - struct file *filp) -{ -} - -/* - * create_buf_file_create() default callback. Creates file to represent buf. - */ -static struct dentry *create_buf_file_default_callback(const char *filename, - struct dentry *parent, - int mode, - struct rchan_buf *buf, - int *is_global) -{ - return relayfs_create_file(filename, parent, mode, - &relay_file_operations, buf); -} - -/* - * remove_buf_file() default callback. Removes file representing relay buffer. - */ -static int remove_buf_file_default_callback(struct dentry *dentry) -{ - return relayfs_remove(dentry); -} - -/* relay channel default callbacks */ -static struct rchan_callbacks default_channel_callbacks = { - .subbuf_start = subbuf_start_default_callback, - .buf_mapped = buf_mapped_default_callback, - .buf_unmapped = buf_unmapped_default_callback, - .create_buf_file = create_buf_file_default_callback, - .remove_buf_file = remove_buf_file_default_callback, -}; - -/** - * wakeup_readers - wake up readers waiting on a channel - * @private: the channel buffer - * - * This is the work function used to defer reader waking. The - * reason waking is deferred is that calling directly from write - * causes problems if you're writing from say the scheduler. - */ -static void wakeup_readers(void *private) -{ - struct rchan_buf *buf = private; - wake_up_interruptible(&buf->read_wait); -} - -/** - * __relay_reset - reset a channel buffer - * @buf: the channel buffer - * @init: 1 if this is a first-time initialization - * - * See relay_reset for description of effect. - */ -static inline void __relay_reset(struct rchan_buf *buf, unsigned int init) -{ - size_t i; - - if (init) { - init_waitqueue_head(&buf->read_wait); - kref_init(&buf->kref); - INIT_WORK(&buf->wake_readers, NULL, NULL); - } else { - cancel_delayed_work(&buf->wake_readers); - flush_scheduled_work(); - } - - buf->subbufs_produced = 0; - buf->subbufs_consumed = 0; - buf->bytes_consumed = 0; - buf->finalized = 0; - buf->data = buf->start; - buf->offset = 0; - - for (i = 0; i < buf->chan->n_subbufs; i++) - buf->padding[i] = 0; - - buf->chan->cb->subbuf_start(buf, buf->data, NULL, 0); -} - -/** - * relay_reset - reset the channel - * @chan: the channel - * - * This has the effect of erasing all data from all channel buffers - * and restarting the channel in its initial state. The buffers - * are not freed, so any mappings are still in effect. - * - * NOTE: Care should be taken that the channel isn't actually - * being used by anything when this call is made. - */ -void relay_reset(struct rchan *chan) -{ - unsigned int i; - struct rchan_buf *prev = NULL; - - if (!chan) - return; - - for (i = 0; i < NR_CPUS; i++) { - if (!chan->buf[i] || chan->buf[i] == prev) - break; - __relay_reset(chan->buf[i], 0); - prev = chan->buf[i]; - } -} - -/** - * relay_open_buf - create a new channel buffer in relayfs - * - * Internal - used by relay_open(). - */ -static struct rchan_buf *relay_open_buf(struct rchan *chan, - const char *filename, - struct dentry *parent, - int *is_global) -{ - struct rchan_buf *buf; - struct dentry *dentry; - - if (*is_global) - return chan->buf[0]; - - buf = relay_create_buf(chan); - if (!buf) - return NULL; - - /* Create file in fs */ - dentry = chan->cb->create_buf_file(filename, parent, S_IRUSR, - buf, is_global); - if (!dentry) { - relay_destroy_buf(buf); - return NULL; - } - - buf->dentry = dentry; - __relay_reset(buf, 1); - - return buf; -} - -/** - * relay_close_buf - close a channel buffer - * @buf: channel buffer - * - * Marks the buffer finalized and restores the default callbacks. - * The channel buffer and channel buffer data structure are then freed - * automatically when the last reference is given up. - */ -static inline void relay_close_buf(struct rchan_buf *buf) -{ - buf->finalized = 1; - buf->chan->cb = &default_channel_callbacks; - cancel_delayed_work(&buf->wake_readers); - flush_scheduled_work(); - kref_put(&buf->kref, relay_remove_buf); -} - -static inline void setup_callbacks(struct rchan *chan, - struct rchan_callbacks *cb) -{ - if (!cb) { - chan->cb = &default_channel_callbacks; - return; - } - - if (!cb->subbuf_start) - cb->subbuf_start = subbuf_start_default_callback; - if (!cb->buf_mapped) - cb->buf_mapped = buf_mapped_default_callback; - if (!cb->buf_unmapped) - cb->buf_unmapped = buf_unmapped_default_callback; - if (!cb->create_buf_file) - cb->create_buf_file = create_buf_file_default_callback; - if (!cb->remove_buf_file) - cb->remove_buf_file = remove_buf_file_default_callback; - chan->cb = cb; -} - -/** - * relay_open - create a new relayfs channel - * @base_filename: base name of files to create - * @parent: dentry of parent directory, NULL for root directory - * @subbuf_size: size of sub-buffers - * @n_subbufs: number of sub-buffers - * @cb: client callback functions - * - * Returns channel pointer if successful, NULL otherwise. - * - * Creates a channel buffer for each cpu using the sizes and - * attributes specified. The created channel buffer files - * will be named base_filename0...base_filenameN-1. File - * permissions will be S_IRUSR. - */ -struct rchan *relay_open(const char *base_filename, - struct dentry *parent, - size_t subbuf_size, - size_t n_subbufs, - struct rchan_callbacks *cb) -{ - unsigned int i; - struct rchan *chan; - char *tmpname; - int is_global = 0; - - if (!base_filename) - return NULL; - - if (!(subbuf_size && n_subbufs)) - return NULL; - - chan = kcalloc(1, sizeof(struct rchan), GFP_KERNEL); - if (!chan) - return NULL; - - chan->version = RELAYFS_CHANNEL_VERSION; - chan->n_subbufs = n_subbufs; - chan->subbuf_size = subbuf_size; - chan->alloc_size = FIX_SIZE(subbuf_size * n_subbufs); - setup_callbacks(chan, cb); - kref_init(&chan->kref); - - tmpname = kmalloc(NAME_MAX + 1, GFP_KERNEL); - if (!tmpname) - goto free_chan; - - for_each_online_cpu(i) { - sprintf(tmpname, "%s%d", base_filename, i); - chan->buf[i] = relay_open_buf(chan, tmpname, parent, - &is_global); - chan->buf[i]->cpu = i; - if (!chan->buf[i]) - goto free_bufs; - } - - kfree(tmpname); - return chan; - -free_bufs: - for (i = 0; i < NR_CPUS; i++) { - if (!chan->buf[i]) - break; - relay_close_buf(chan->buf[i]); - if (is_global) - break; - } - kfree(tmpname); - -free_chan: - kref_put(&chan->kref, relay_destroy_channel); - return NULL; -} - -/** - * relay_switch_subbuf - switch to a new sub-buffer - * @buf: channel buffer - * @length: size of current event - * - * Returns either the length passed in or 0 if full. - - * Performs sub-buffer-switch tasks such as invoking callbacks, - * updating padding counts, waking up readers, etc. - */ -size_t relay_switch_subbuf(struct rchan_buf *buf, size_t length) -{ - void *old, *new; - size_t old_subbuf, new_subbuf; - - if (unlikely(length > buf->chan->subbuf_size)) - goto toobig; - - if (buf->offset != buf->chan->subbuf_size + 1) { - buf->prev_padding = buf->chan->subbuf_size - buf->offset; - old_subbuf = buf->subbufs_produced % buf->chan->n_subbufs; - buf->padding[old_subbuf] = buf->prev_padding; - buf->subbufs_produced++; - if (waitqueue_active(&buf->read_wait)) { - PREPARE_WORK(&buf->wake_readers, wakeup_readers, buf); - schedule_delayed_work(&buf->wake_readers, 1); - } - } - - old = buf->data; - new_subbuf = buf->subbufs_produced % buf->chan->n_subbufs; - new = buf->start + new_subbuf * buf->chan->subbuf_size; - buf->offset = 0; - if (!buf->chan->cb->subbuf_start(buf, new, old, buf->prev_padding)) { - buf->offset = buf->chan->subbuf_size + 1; - return 0; - } - buf->data = new; - buf->padding[new_subbuf] = 0; - - if (unlikely(length + buf->offset > buf->chan->subbuf_size)) - goto toobig; - - return length; - -toobig: - buf->chan->last_toobig = length; - return 0; -} - -/** - * relay_subbufs_consumed - update the buffer's sub-buffers-consumed count - * @chan: the channel - * @cpu: the cpu associated with the channel buffer to update - * @subbufs_consumed: number of sub-buffers to add to current buf's count - * - * Adds to the channel buffer's consumed sub-buffer count. - * subbufs_consumed should be the number of sub-buffers newly consumed, - * not the total consumed. - * - * NOTE: kernel clients don't need to call this function if the channel - * mode is 'overwrite'. - */ -void relay_subbufs_consumed(struct rchan *chan, - unsigned int cpu, - size_t subbufs_consumed) -{ - struct rchan_buf *buf; - - if (!chan) - return; - - if (cpu >= NR_CPUS || !chan->buf[cpu]) - return; - - buf = chan->buf[cpu]; - buf->subbufs_consumed += subbufs_consumed; - if (buf->subbufs_consumed > buf->subbufs_produced) - buf->subbufs_consumed = buf->subbufs_produced; -} - -/** - * relay_destroy_channel - free the channel struct - * - * Should only be called from kref_put(). - */ -void relay_destroy_channel(struct kref *kref) -{ - struct rchan *chan = container_of(kref, struct rchan, kref); - kfree(chan); -} - -/** - * relay_close - close the channel - * @chan: the channel - * - * Closes all channel buffers and frees the channel. - */ -void relay_close(struct rchan *chan) -{ - unsigned int i; - struct rchan_buf *prev = NULL; - - if (!chan) - return; - - for (i = 0; i < NR_CPUS; i++) { - if (!chan->buf[i] || chan->buf[i] == prev) - break; - relay_close_buf(chan->buf[i]); - prev = chan->buf[i]; - } - - if (chan->last_toobig) - printk(KERN_WARNING "relayfs: one or more items not logged " - "[item size (%Zd) > sub-buffer size (%Zd)]\n", - chan->last_toobig, chan->subbuf_size); - - kref_put(&chan->kref, relay_destroy_channel); -} - -/** - * relay_flush - close the channel - * @chan: the channel - * - * Flushes all channel buffers i.e. forces buffer switch. - */ -void relay_flush(struct rchan *chan) -{ - unsigned int i; - struct rchan_buf *prev = NULL; - - if (!chan) - return; - - for (i = 0; i < NR_CPUS; i++) { - if (!chan->buf[i] || chan->buf[i] == prev) - break; - relay_switch_subbuf(chan->buf[i], 0); - prev = chan->buf[i]; - } -} - -EXPORT_SYMBOL_GPL(relay_open); -EXPORT_SYMBOL_GPL(relay_close); -EXPORT_SYMBOL_GPL(relay_flush); -EXPORT_SYMBOL_GPL(relay_reset); -EXPORT_SYMBOL_GPL(relay_subbufs_consumed); -EXPORT_SYMBOL_GPL(relay_switch_subbuf); -EXPORT_SYMBOL_GPL(relay_buf_full); |