-/*
- * Public API and common code for kernel->userspace relay file support.
- *
- * Copyright (C) 2002-2005 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp
- * Copyright (C) 1999-2005 - Karim Yaghmour (karim@opersys.com)
- * Copyright (C) 2008 - Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca)
- *
- * Moved to kernel/relay.c by Paul Mundt, 2006.
- * November 2006 - CPU hotplug support by Mathieu Desnoyers
- * (mathieu.desnoyers@polymtl.ca)
- *
- * This file is released under the GPL.
- */
-//ust// #include <linux/errno.h>
-//ust// #include <linux/stddef.h>
-//ust// #include <linux/slab.h>
-//ust// #include <linux/module.h>
-//ust// #include <linux/string.h>
-//ust// #include <linux/ltt-relay.h>
-//ust// #include <linux/vmalloc.h>
-//ust// #include <linux/mm.h>
-//ust// #include <linux/cpu.h>
-//ust// #include <linux/splice.h>
-//ust// #include <linux/bitops.h>
-#include <sys/mman.h>
-#include "kernelcompat.h"
-#include "list.h"
-#include "relay.h"
-#include "channels.h"
-#include "kref.h"
-
-/* list of open channels, for cpu hotplug */
-static DEFINE_MUTEX(relay_channels_mutex);
-static LIST_HEAD(relay_channels);
-
-/**
- * relay_alloc_buf - allocate a channel buffer
- * @buf: the buffer struct
- * @size: total size of the buffer
- */
-//ust// static int relay_alloc_buf(struct rchan_buf *buf, size_t *size)
-//ust//{
-//ust// unsigned int i, n_pages;
-//ust// struct buf_page *buf_page, *n;
-//ust//
-//ust// *size = PAGE_ALIGN(*size);
-//ust// n_pages = *size >> PAGE_SHIFT;
-//ust//
-//ust// INIT_LIST_HEAD(&buf->pages);
-//ust//
-//ust// for (i = 0; i < n_pages; i++) {
-//ust// buf_page = kmalloc_node(sizeof(*buf_page), GFP_KERNEL,
-//ust// cpu_to_node(buf->cpu));
-//ust// if (unlikely(!buf_page))
-//ust// goto depopulate;
-//ust// buf_page->page = alloc_pages_node(cpu_to_node(buf->cpu),
-//ust// GFP_KERNEL | __GFP_ZERO, 0);
-//ust// if (unlikely(!buf_page->page)) {
-//ust// kfree(buf_page);
-//ust// goto depopulate;
-//ust// }
-//ust// list_add_tail(&buf_page->list, &buf->pages);
-//ust// buf_page->offset = (size_t)i << PAGE_SHIFT;
-//ust// buf_page->buf = buf;
-//ust// set_page_private(buf_page->page, (unsigned long)buf_page);
-//ust// if (i == 0) {
-//ust// buf->wpage = buf_page;
-//ust// buf->hpage[0] = buf_page;
-//ust// buf->hpage[1] = buf_page;
-//ust// buf->rpage = buf_page;
-//ust// }
-//ust// }
-//ust// buf->page_count = n_pages;
-//ust// return 0;
-//ust//
-//ust//depopulate:
-//ust// list_for_each_entry_safe(buf_page, n, &buf->pages, list) {
-//ust// list_del_init(&buf_page->list);
-//ust// __free_page(buf_page->page);
-//ust// kfree(buf_page);
-//ust// }
-//ust// return -ENOMEM;
-//ust//}
-
-static int relay_alloc_buf(struct rchan_buf *buf, size_t *size)
-{
- unsigned int n_pages;
- struct buf_page *buf_page, *n;
-
- void *result;
-
- *size = PAGE_ALIGN(*size);
-
- /* Maybe do read-ahead */
- result = mmap(NULL, *size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS, -1, 0);
- if(result == MAP_FAILED) {
- PERROR("mmap");
- return -1;
- }
-
- buf->buf_data = result;
- buf->buf_size = *size;
-
- return 0;
-}
-
-/**
- * relay_create_buf - allocate and initialize a channel buffer
- * @chan: the relay channel
- * @cpu: cpu the buffer belongs to
- *
- * Returns channel buffer if successful, %NULL otherwise.
- */
-static struct rchan_buf *relay_create_buf(struct rchan *chan, int cpu)
-{
- int ret;
- struct rchan_buf *buf = kzalloc(sizeof(struct rchan_buf), GFP_KERNEL);
- if (!buf)
- return NULL;
-
-// buf->cpu = cpu;
- ret = relay_alloc_buf(buf, &chan->alloc_size);
- if (ret)
- goto free_buf;
-
- buf->chan = chan;
- kref_get(&buf->chan->kref);
- return buf;
-
-free_buf:
- kfree(buf);
- return NULL;
-}
-
-/**
- * relay_destroy_channel - free the channel struct
- * @kref: target kernel reference that contains the relay channel
- *
- * Should only be called from kref_put().
- */
-static void relay_destroy_channel(struct kref *kref)
-{
- struct rchan *chan = container_of(kref, struct rchan, kref);
- kfree(chan);
-}
-
-/**
- * relay_destroy_buf - destroy an rchan_buf struct and associated buffer
- * @buf: the buffer struct
- */
-static void relay_destroy_buf(struct rchan_buf *buf)
-{
- struct rchan *chan = buf->chan;
- struct buf_page *buf_page, *n;
- int result;
-
- result = munmap(buf->buf_data, buf->buf_size);
- if(result == -1) {
- PERROR("munmap");
-
-//ust// chan->buf[buf->cpu] = NULL;
- kfree(buf);
- kref_put(&chan->kref, relay_destroy_channel);
-}
-
-/**
- * relay_remove_buf - remove a channel buffer
- * @kref: target kernel reference that contains the relay buffer
- *
- * Removes the file from the fileystem, which also frees the
- * rchan_buf_struct and the channel buffer. Should only be called from
- * kref_put().
- */
-static void relay_remove_buf(struct kref *kref)
-{
- struct rchan_buf *buf = container_of(kref, struct rchan_buf, kref);
- buf->chan->cb->remove_buf_file(buf->dentry);
- relay_destroy_buf(buf);
-}
-
-/*
- * High-level relay kernel API and associated functions.
- */
-
-/*
- * rchan_callback implementations defining default channel behavior. Used
- * in place of corresponding NULL values in client callback struct.
- */
-
-/*
- * create_buf_file_create() default callback. Does nothing.
- */
-static struct dentry *create_buf_file_default_callback(const char *filename,
- struct dentry *parent,
- int mode,
- struct rchan_buf *buf)
-{
- return NULL;
-}
-
-/*
- * remove_buf_file() default callback. Does nothing.
- */
-static int remove_buf_file_default_callback(struct dentry *dentry)
-{
- return -EINVAL;
-}
-
-/* relay channel default callbacks */
-static struct rchan_callbacks default_channel_callbacks = {
- .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
- * @data: contains the channel buffer
- *
- * This is the timer function used to defer reader waking.
- */
-static void wakeup_readers(unsigned long data)
-{
- struct rchan_buf *buf = (struct rchan_buf *)data;
- 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 void __relay_reset(struct rchan_buf *buf, unsigned int init)
-{
- if (init) {
- init_waitqueue_head(&buf->read_wait);
- kref_init(&buf->kref);
- setup_timer(&buf->timer, wakeup_readers, (unsigned long)buf);
- } else
- del_timer_sync(&buf->timer);
-
- buf->finalized = 0;
-}
-
-/*
- * relay_open_buf - create a new relay channel buffer
- *
- * used by relay_open() and CPU hotplug.
- */
-static struct rchan_buf *relay_open_buf(struct rchan *chan, unsigned int cpu)
-{
- struct rchan_buf *buf = NULL;
- struct dentry *dentry;
- char *tmpname;
-
- tmpname = kzalloc(NAME_MAX + 1, GFP_KERNEL);
- if (!tmpname)
- goto end;
- snprintf(tmpname, NAME_MAX, "%s%d", chan->base_filename, cpu);
-
- buf = relay_create_buf(chan, cpu);
- if (!buf)
- goto free_name;
-
- __relay_reset(buf, 1);
-
- /* Create file in fs */
-//ust// dentry = chan->cb->create_buf_file(tmpname, chan->parent, S_IRUSR,
-//ust// buf);
-//ust// if (!dentry)
-//ust// goto free_buf;
-//ust//
-//ust// buf->dentry = dentry;
-
- goto free_name;
-
-free_buf:
- relay_destroy_buf(buf);
- buf = NULL;
-free_name:
- kfree(tmpname);
-end:
- 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 void relay_close_buf(struct rchan_buf *buf)
-{
- del_timer_sync(&buf->timer);
- kref_put(&buf->kref, relay_remove_buf);
-}
-
-static void setup_callbacks(struct rchan *chan,
- struct rchan_callbacks *cb)
-{
- if (!cb) {
- chan->cb = &default_channel_callbacks;
- return;
- }
-
- 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_hotcpu_callback - CPU hotplug callback
- * @nb: notifier block
- * @action: hotplug action to take
- * @hcpu: CPU number
- *
- * Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD)
- */
-//ust// static int __cpuinit relay_hotcpu_callback(struct notifier_block *nb,
-//ust// unsigned long action,
-//ust// void *hcpu)
-//ust// {
-//ust// unsigned int hotcpu = (unsigned long)hcpu;
-//ust// struct rchan *chan;
-//ust//
-//ust// switch (action) {
-//ust// case CPU_UP_PREPARE:
-//ust// case CPU_UP_PREPARE_FROZEN:
-//ust// mutex_lock(&relay_channels_mutex);
-//ust// list_for_each_entry(chan, &relay_channels, list) {
-//ust// if (chan->buf[hotcpu])
-//ust// continue;
-//ust// chan->buf[hotcpu] = relay_open_buf(chan, hotcpu);
-//ust// if (!chan->buf[hotcpu]) {
-//ust// printk(KERN_ERR
-//ust// "relay_hotcpu_callback: cpu %d buffer "
-//ust// "creation failed\n", hotcpu);
-//ust// mutex_unlock(&relay_channels_mutex);
-//ust// return NOTIFY_BAD;
-//ust// }
-//ust// }
-//ust// mutex_unlock(&relay_channels_mutex);
-//ust// break;
-//ust// case CPU_DEAD:
-//ust// case CPU_DEAD_FROZEN:
-//ust// /* No need to flush the cpu : will be flushed upon
-//ust// * final relay_flush() call. */
-//ust// break;
-//ust// }
-//ust// return NOTIFY_OK;
-//ust// }
-
-/**
- * ltt_relay_open - create a new relay 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
- * @private_data: user-defined data
- *
- * 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 *ltt_relay_open(const char *base_filename,
- struct dentry *parent,
- size_t subbuf_size,
- size_t n_subbufs,
- struct rchan_callbacks *cb,
- void *private_data)
-{
- unsigned int i;
- struct rchan *chan;
- if (!base_filename)
- return NULL;
-
- if (!(subbuf_size && n_subbufs))
- return NULL;
-
- chan = kzalloc(sizeof(struct rchan), GFP_KERNEL);
- if (!chan)
- return NULL;
-
- chan->version = LTT_RELAY_CHANNEL_VERSION;
- chan->n_subbufs = n_subbufs;
- chan->subbuf_size = subbuf_size;
- chan->subbuf_size_order = get_count_order(subbuf_size);
- chan->alloc_size = FIX_SIZE(subbuf_size * n_subbufs);
- chan->parent = parent;
- chan->private_data = private_data;
- strlcpy(chan->base_filename, base_filename, NAME_MAX);
- setup_callbacks(chan, cb);
- kref_init(&chan->kref);
-
- mutex_lock(&relay_channels_mutex);
- for_each_online_cpu(i) {
- chan->buf[i] = relay_open_buf(chan, i);
- if (!chan->buf[i])
- goto free_bufs;
- }
- list_add(&chan->list, &relay_channels);
- mutex_unlock(&relay_channels_mutex);
-
- return chan;
-
-free_bufs:
- for_each_possible_cpu(i) {
- if (!chan->buf[i])
- break;
- relay_close_buf(chan->buf[i]);
- }
-
- kref_put(&chan->kref, relay_destroy_channel);
- mutex_unlock(&relay_channels_mutex);
- return NULL;
-}
-EXPORT_SYMBOL_GPL(ltt_relay_open);
-
-/**
- * ltt_relay_close - close the channel
- * @chan: the channel
- *
- * Closes all channel buffers and frees the channel.
- */
-void ltt_relay_close(struct rchan *chan)
-{
- unsigned int i;
-
- if (!chan)
- return;
-
- mutex_lock(&relay_channels_mutex);
- for_each_possible_cpu(i)
- if (chan->buf[i])
- relay_close_buf(chan->buf[i]);
-
- list_del(&chan->list);
- kref_put(&chan->kref, relay_destroy_channel);
- mutex_unlock(&relay_channels_mutex);
-}
-EXPORT_SYMBOL_GPL(ltt_relay_close);
-
-/*
- * Start iteration at the previous element. Skip the real list head.
- */
-struct buf_page *ltt_relay_find_prev_page(struct rchan_buf *buf,
- struct buf_page *page, size_t offset, ssize_t diff_offset)
-{
- struct buf_page *iter;
- size_t orig_iter_off;
- unsigned int i = 0;
-
- orig_iter_off = page->offset;
- list_for_each_entry_reverse(iter, &page->list, list) {
- /*
- * Skip the real list head.
- */
- if (&iter->list == &buf->pages)
- continue;
- i++;
- if (offset >= iter->offset
- && offset < iter->offset + PAGE_SIZE) {
-#ifdef CONFIG_LTT_RELAY_CHECK_RANDOM_ACCESS
- if (i > 1) {
- printk(KERN_WARNING
- "Backward random access detected in "
- "ltt_relay. Iterations %u, "
- "offset %zu, orig iter->off %zu, "
- "iter->off %zu diff_offset %zd.\n", i,
- offset, orig_iter_off, iter->offset,
- diff_offset);
- WARN_ON(1);
- }
-#endif
- return iter;
- }
- }
- WARN_ON(1);
- return NULL;
-}
-EXPORT_SYMBOL_GPL(ltt_relay_find_prev_page);
-
-/*
- * Start iteration at the next element. Skip the real list head.
- */
-struct buf_page *ltt_relay_find_next_page(struct rchan_buf *buf,
- struct buf_page *page, size_t offset, ssize_t diff_offset)
-{
- struct buf_page *iter;
- unsigned int i = 0;
- size_t orig_iter_off;
-
- orig_iter_off = page->offset;
- list_for_each_entry(iter, &page->list, list) {
- /*
- * Skip the real list head.
- */
- if (&iter->list == &buf->pages)
- continue;
- i++;
- if (offset >= iter->offset
- && offset < iter->offset + PAGE_SIZE) {
-#ifdef CONFIG_LTT_RELAY_CHECK_RANDOM_ACCESS
- if (i > 1) {
- printk(KERN_WARNING
- "Forward random access detected in "
- "ltt_relay. Iterations %u, "
- "offset %zu, orig iter->off %zu, "
- "iter->off %zu diff_offset %zd.\n", i,
- offset, orig_iter_off, iter->offset,
- diff_offset);
- WARN_ON(1);
- }
-#endif
- return iter;
- }
- }
- WARN_ON(1);
- return NULL;
-}
-EXPORT_SYMBOL_GPL(ltt_relay_find_next_page);
-
-/**
- * ltt_relay_write - write data to a ltt_relay buffer.
- * @buf : buffer
- * @offset : offset within the buffer
- * @src : source address
- * @len : length to write
- * @page : cached buffer page
- * @pagecpy : page size copied so far
- */
-void _ltt_relay_write(struct rchan_buf *buf, size_t offset,
- const void *src, size_t len, struct buf_page *page, ssize_t pagecpy)
-{
- do {
- len -= pagecpy;
- src += pagecpy;
- offset += pagecpy;
- /*
- * Underlying layer should never ask for writes across
- * subbuffers.
- */
- WARN_ON(offset >= buf->chan->alloc_size);
-
- page = ltt_relay_cache_page(buf, &buf->wpage, page, offset);
- pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK));
- ltt_relay_do_copy(page_address(page->page)
- + (offset & ~PAGE_MASK), src, pagecpy);
- } while (unlikely(len != pagecpy));
-}
-EXPORT_SYMBOL_GPL(_ltt_relay_write);
-
-/**
- * ltt_relay_read - read data from ltt_relay_buffer.
- * @buf : buffer
- * @offset : offset within the buffer
- * @dest : destination address
- * @len : length to write
- */
-int ltt_relay_read(struct rchan_buf *buf, size_t offset,
- void *dest, size_t len)
-{
- struct buf_page *page;
- ssize_t pagecpy, orig_len;
-
- orig_len = len;
- offset &= buf->chan->alloc_size - 1;
- page = buf->rpage;
- if (unlikely(!len))
- return 0;
- for (;;) {
- page = ltt_relay_cache_page(buf, &buf->rpage, page, offset);
- pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK));
- memcpy(dest, page_address(page->page) + (offset & ~PAGE_MASK),
- pagecpy);
- len -= pagecpy;
- if (likely(!len))
- break;
- dest += pagecpy;
- offset += pagecpy;
- /*
- * Underlying layer should never ask for reads across
- * subbuffers.
- */
- WARN_ON(offset >= buf->chan->alloc_size);
- }
- return orig_len;
-}
-EXPORT_SYMBOL_GPL(ltt_relay_read);
-
-/**
- * ltt_relay_read_get_page - Get a whole page to read from
- * @buf : buffer
- * @offset : offset within the buffer
- */
-//ust// struct buf_page *ltt_relay_read_get_page(struct rchan_buf *buf, size_t offset)
-//ust// {
-//ust// struct buf_page *page;
-
-//ust// offset &= buf->chan->alloc_size - 1;
-//ust// page = buf->rpage;
-//ust// page = ltt_relay_cache_page(buf, &buf->rpage, page, offset);
-//ust// return page;
-//ust// }
-//ust// EXPORT_SYMBOL_GPL(ltt_relay_read_get_page);
-
-/**
- * ltt_relay_offset_address - get address of a location within the buffer
- * @buf : buffer
- * @offset : offset within the buffer.
- *
- * Return the address where a given offset is located.
- * Should be used to get the current subbuffer header pointer. Given we know
- * it's never on a page boundary, it's safe to write directly to this address,
- * as long as the write is never bigger than a page size.
- */
-void *ltt_relay_offset_address(struct rchan_buf *buf, size_t offset)
-{
- struct buf_page *page;
- unsigned int odd;
-
- offset &= buf->chan->alloc_size - 1;
- odd = !!(offset & buf->chan->subbuf_size);
- page = buf->hpage[odd];
- if (offset < page->offset || offset >= page->offset + PAGE_SIZE)
- buf->hpage[odd] = page = buf->wpage;
- page = ltt_relay_cache_page(buf, &buf->hpage[odd], page, offset);
- return page_address(page->page) + (offset & ~PAGE_MASK);
-}
-//ust// EXPORT_SYMBOL_GPL(ltt_relay_offset_address);
-
-/**
- * relay_file_open - open file op for relay files
- * @inode: the inode
- * @filp: the file
- *
- * Increments the channel buffer refcount.
- */
-//ust// static int relay_file_open(struct inode *inode, struct file *filp)
-//ust// {
-//ust// struct rchan_buf *buf = inode->i_private;
-//ust// kref_get(&buf->kref);
-//ust// filp->private_data = buf;
-//ust//
-//ust// return nonseekable_open(inode, filp);
-//ust// }
-
-/**
- * relay_file_release - release file op for relay files
- * @inode: the inode
- * @filp: the file
- *
- * Decrements the channel refcount, as the filesystem is
- * no longer using it.
- */
-static int relay_file_release(struct inode *inode, struct file *filp)
-{
- struct rchan_buf *buf = filp->private_data;
- kref_put(&buf->kref, relay_remove_buf);
-
- return 0;
-}
-
-//ust// const struct file_operations ltt_relay_file_operations = {
-//ust// .open = relay_file_open,
-//ust// .release = relay_file_release,
-//ust// };
-//ust// EXPORT_SYMBOL_GPL(ltt_relay_file_operations);
-
-//ust// static __init int relay_init(void)
-//ust// {
-//ust// hotcpu_notifier(relay_hotcpu_callback, 5);
-//ust// return 0;
-//ust// }
-
-//ust// module_init(relay_init);
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