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 abf3ceaace4..00000000000 --- 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); | 
