+++ /dev/null
-/*
- * ring_buffer_backend.c
- *
- * Copyright (C) 2005-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * Dual LGPL v2.1/GPL v2 license.
- */
-
-#include "config.h"
-#include "backend.h"
-#include "frontend.h"
-
-/**
- * lib_ring_buffer_backend_allocate - allocate a channel buffer
- * @config: ring buffer instance configuration
- * @buf: the buffer struct
- * @size: total size of the buffer
- * @num_subbuf: number of subbuffers
- * @extra_reader_sb: need extra subbuffer for reader
- */
-static
-int lib_ring_buffer_backend_allocate(const struct lib_ring_buffer_config *config,
- struct lib_ring_buffer_backend *bufb,
- size_t size, size_t num_subbuf,
- int extra_reader_sb)
-{
- struct channel_backend *chanb = &bufb->chan->backend;
- unsigned long j, num_pages, num_pages_per_subbuf, page_idx = 0;
- unsigned long subbuf_size, mmap_offset = 0;
- unsigned long num_subbuf_alloc;
- struct page **pages;
- void **virt;
- unsigned long i;
-
- num_pages = size >> PAGE_SHIFT;
- num_pages_per_subbuf = num_pages >> get_count_order(num_subbuf);
- subbuf_size = chanb->subbuf_size;
- num_subbuf_alloc = num_subbuf;
-
- if (extra_reader_sb) {
- num_pages += num_pages_per_subbuf; /* Add pages for reader */
- num_subbuf_alloc++;
- }
-
- pages = kmalloc_node(ALIGN(sizeof(*pages) * num_pages,
- 1 << INTERNODE_CACHE_SHIFT),
- GFP_KERNEL, cpu_to_node(max(bufb->cpu, 0)));
- if (unlikely(!pages))
- goto pages_error;
-
- virt = kmalloc_node(ALIGN(sizeof(*virt) * num_pages,
- 1 << INTERNODE_CACHE_SHIFT),
- GFP_KERNEL, cpu_to_node(max(bufb->cpu, 0)));
- if (unlikely(!virt))
- goto virt_error;
-
- bufb->array = kmalloc_node(ALIGN(sizeof(*bufb->array)
- * num_subbuf_alloc,
- 1 << INTERNODE_CACHE_SHIFT),
- GFP_KERNEL, cpu_to_node(max(bufb->cpu, 0)));
- if (unlikely(!bufb->array))
- goto array_error;
-
- for (i = 0; i < num_pages; i++) {
- pages[i] = alloc_pages_node(cpu_to_node(max(bufb->cpu, 0)),
- GFP_KERNEL | __GFP_ZERO, 0);
- if (unlikely(!pages[i]))
- goto depopulate;
- virt[i] = page_address(pages[i]);
- }
- bufb->num_pages_per_subbuf = num_pages_per_subbuf;
-
- /* Allocate backend pages array elements */
- for (i = 0; i < num_subbuf_alloc; i++) {
- bufb->array[i] =
- kzalloc_node(ALIGN(
- sizeof(struct lib_ring_buffer_backend_pages) +
- sizeof(struct lib_ring_buffer_backend_page)
- * num_pages_per_subbuf,
- 1 << INTERNODE_CACHE_SHIFT),
- GFP_KERNEL, cpu_to_node(max(bufb->cpu, 0)));
- if (!bufb->array[i])
- goto free_array;
- }
-
- /* Allocate write-side subbuffer table */
- bufb->buf_wsb = kzalloc_node(ALIGN(
- sizeof(struct lib_ring_buffer_backend_subbuffer)
- * num_subbuf,
- 1 << INTERNODE_CACHE_SHIFT),
- GFP_KERNEL, cpu_to_node(max(bufb->cpu, 0)));
- if (unlikely(!bufb->buf_wsb))
- goto free_array;
-
- for (i = 0; i < num_subbuf; i++)
- bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i);
-
- /* Assign read-side subbuffer table */
- if (extra_reader_sb)
- bufb->buf_rsb.id = subbuffer_id(config, 0, 1,
- num_subbuf_alloc - 1);
- else
- bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0);
-
- /* Assign pages to page index */
- for (i = 0; i < num_subbuf_alloc; i++) {
- for (j = 0; j < num_pages_per_subbuf; j++) {
- CHAN_WARN_ON(chanb, page_idx > num_pages);
- bufb->array[i]->p[j].virt = virt[page_idx];
- bufb->array[i]->p[j].page = pages[page_idx];
- page_idx++;
- }
- if (config->output == RING_BUFFER_MMAP) {
- bufb->array[i]->mmap_offset = mmap_offset;
- mmap_offset += subbuf_size;
- }
- }
-
- /*
- * If kmalloc ever uses vmalloc underneath, make sure the buffer pages
- * will not fault.
- */
- wrapper_vmalloc_sync_all();
- kfree(virt);
- kfree(pages);
- return 0;
-
-free_array:
- for (i = 0; (i < num_subbuf_alloc && bufb->array[i]); i++)
- kfree(bufb->array[i]);
-depopulate:
- /* Free all allocated pages */
- for (i = 0; (i < num_pages && pages[i]); i++)
- __free_page(pages[i]);
- kfree(bufb->array);
-array_error:
- kfree(virt);
-virt_error:
- kfree(pages);
-pages_error:
- return -ENOMEM;
-}
-
-int lib_ring_buffer_backend_create(struct lib_ring_buffer_backend *bufb,
- struct channel_backend *chanb, int cpu)
-{
- const struct lib_ring_buffer_config *config = chanb->config;
-
- bufb->chan = container_of(chanb, struct channel, backend);
- bufb->cpu = cpu;
-
- return lib_ring_buffer_backend_allocate(config, bufb, chanb->buf_size,
- chanb->num_subbuf,
- chanb->extra_reader_sb);
-}
-
-void lib_ring_buffer_backend_free(struct lib_ring_buffer_backend *bufb)
-{
- struct channel_backend *chanb = &bufb->chan->backend;
- unsigned long i, j, num_subbuf_alloc;
-
- num_subbuf_alloc = chanb->num_subbuf;
- if (chanb->extra_reader_sb)
- num_subbuf_alloc++;
-
- kfree(bufb->buf_wsb);
- for (i = 0; i < num_subbuf_alloc; i++) {
- for (j = 0; j < bufb->num_pages_per_subbuf; j++)
- __free_page(bufb->array[i]->p[j].page);
- kfree(bufb->array[i]);
- }
- kfree(bufb->array);
- bufb->allocated = 0;
-}
-
-void lib_ring_buffer_backend_reset(struct lib_ring_buffer_backend *bufb)
-{
- struct channel_backend *chanb = &bufb->chan->backend;
- const struct lib_ring_buffer_config *config = chanb->config;
- unsigned long num_subbuf_alloc;
- unsigned int i;
-
- num_subbuf_alloc = chanb->num_subbuf;
- if (chanb->extra_reader_sb)
- num_subbuf_alloc++;
-
- for (i = 0; i < chanb->num_subbuf; i++)
- bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i);
- if (chanb->extra_reader_sb)
- bufb->buf_rsb.id = subbuffer_id(config, 0, 1,
- num_subbuf_alloc - 1);
- else
- bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0);
-
- for (i = 0; i < num_subbuf_alloc; i++) {
- /* Don't reset mmap_offset */
- v_set(config, &bufb->array[i]->records_commit, 0);
- v_set(config, &bufb->array[i]->records_unread, 0);
- bufb->array[i]->data_size = 0;
- /* Don't reset backend page and virt addresses */
- }
- /* Don't reset num_pages_per_subbuf, cpu, allocated */
- v_set(config, &bufb->records_read, 0);
-}
-
-/*
- * The frontend is responsible for also calling ring_buffer_backend_reset for
- * each buffer when calling channel_backend_reset.
- */
-void channel_backend_reset(struct channel_backend *chanb)
-{
- struct channel *chan = container_of(chanb, struct channel, backend);
- const struct lib_ring_buffer_config *config = chanb->config;
-
- /*
- * Don't reset buf_size, subbuf_size, subbuf_size_order,
- * num_subbuf_order, buf_size_order, extra_reader_sb, num_subbuf,
- * priv, notifiers, config, cpumask and name.
- */
- chanb->start_tsc = config->cb.ring_buffer_clock_read(chan);
-}
-
-#ifdef CONFIG_HOTPLUG_CPU
-/**
- * lib_ring_buffer_cpu_hp_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)
- */
-static
-int __cpuinit lib_ring_buffer_cpu_hp_callback(struct notifier_block *nb,
- unsigned long action,
- void *hcpu)
-{
- unsigned int cpu = (unsigned long)hcpu;
- struct channel_backend *chanb = container_of(nb, struct channel_backend,
- cpu_hp_notifier);
- const struct lib_ring_buffer_config *config = chanb->config;
- struct lib_ring_buffer *buf;
- int ret;
-
- CHAN_WARN_ON(chanb, config->alloc == RING_BUFFER_ALLOC_GLOBAL);
-
- switch (action) {
- case CPU_UP_PREPARE:
- case CPU_UP_PREPARE_FROZEN:
- buf = per_cpu_ptr(chanb->buf, cpu);
- ret = lib_ring_buffer_create(buf, chanb, cpu);
- if (ret) {
- printk(KERN_ERR
- "ring_buffer_cpu_hp_callback: cpu %d "
- "buffer creation failed\n", cpu);
- return NOTIFY_BAD;
- }
- break;
- case CPU_DEAD:
- case CPU_DEAD_FROZEN:
- /* No need to do a buffer switch here, because it will happen
- * when tracing is stopped, or will be done by switch timer CPU
- * DEAD callback. */
- break;
- }
- return NOTIFY_OK;
-}
-#endif
-
-/**
- * channel_backend_init - initialize a channel backend
- * @chanb: channel backend
- * @name: channel name
- * @config: client ring buffer configuration
- * @priv: client private data
- * @parent: dentry of parent directory, %NULL for root directory
- * @subbuf_size: size of sub-buffers (> PAGE_SIZE, power of 2)
- * @num_subbuf: number of sub-buffers (power of 2)
- *
- * Returns channel pointer if successful, %NULL otherwise.
- *
- * Creates per-cpu channel buffers using the sizes and attributes
- * specified. The created channel buffer files will be named
- * name_0...name_N-1. File permissions will be %S_IRUSR.
- *
- * Called with CPU hotplug disabled.
- */
-int channel_backend_init(struct channel_backend *chanb,
- const char *name,
- const struct lib_ring_buffer_config *config,
- void *priv, size_t subbuf_size, size_t num_subbuf)
-{
- struct channel *chan = container_of(chanb, struct channel, backend);
- unsigned int i;
- int ret;
-
- if (!name)
- return -EPERM;
-
- if (!(subbuf_size && num_subbuf))
- return -EPERM;
-
- /* Check that the subbuffer size is larger than a page. */
- if (subbuf_size < PAGE_SIZE)
- return -EINVAL;
-
- /*
- * Make sure the number of subbuffers and subbuffer size are power of 2.
- */
- CHAN_WARN_ON(chanb, hweight32(subbuf_size) != 1);
- CHAN_WARN_ON(chanb, hweight32(num_subbuf) != 1);
-
- ret = subbuffer_id_check_index(config, num_subbuf);
- if (ret)
- return ret;
-
- chanb->priv = priv;
- chanb->buf_size = num_subbuf * subbuf_size;
- chanb->subbuf_size = subbuf_size;
- chanb->buf_size_order = get_count_order(chanb->buf_size);
- chanb->subbuf_size_order = get_count_order(subbuf_size);
- chanb->num_subbuf_order = get_count_order(num_subbuf);
- chanb->extra_reader_sb =
- (config->mode == RING_BUFFER_OVERWRITE) ? 1 : 0;
- chanb->num_subbuf = num_subbuf;
- strlcpy(chanb->name, name, NAME_MAX);
- chanb->config = config;
-
- if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
- if (!zalloc_cpumask_var(&chanb->cpumask, GFP_KERNEL))
- return -ENOMEM;
- }
-
- if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
- /* Allocating the buffer per-cpu structures */
- chanb->buf = alloc_percpu(struct lib_ring_buffer);
- if (!chanb->buf)
- goto free_cpumask;
-
- /*
- * In case of non-hotplug cpu, if the ring-buffer is allocated
- * in early initcall, it will not be notified of secondary cpus.
- * In that off case, we need to allocate for all possible cpus.
- */
-#ifdef CONFIG_HOTPLUG_CPU
- /*
- * buf->backend.allocated test takes care of concurrent CPU
- * hotplug.
- * Priority higher than frontend, so we create the ring buffer
- * before we start the timer.
- */
- chanb->cpu_hp_notifier.notifier_call =
- lib_ring_buffer_cpu_hp_callback;
- chanb->cpu_hp_notifier.priority = 5;
- register_hotcpu_notifier(&chanb->cpu_hp_notifier);
-
- get_online_cpus();
- for_each_online_cpu(i) {
- ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i),
- chanb, i);
- if (ret)
- goto free_bufs; /* cpu hotplug locked */
- }
- put_online_cpus();
-#else
- for_each_possible_cpu(i) {
- ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i),
- chanb, i);
- if (ret)
- goto free_bufs; /* cpu hotplug locked */
- }
-#endif
- } else {
- chanb->buf = kzalloc(sizeof(struct lib_ring_buffer), GFP_KERNEL);
- if (!chanb->buf)
- goto free_cpumask;
- ret = lib_ring_buffer_create(chanb->buf, chanb, -1);
- if (ret)
- goto free_bufs;
- }
- chanb->start_tsc = config->cb.ring_buffer_clock_read(chan);
-
- return 0;
-
-free_bufs:
- if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
- for_each_possible_cpu(i) {
- struct lib_ring_buffer *buf = per_cpu_ptr(chanb->buf, i);
-
- if (!buf->backend.allocated)
- continue;
- lib_ring_buffer_free(buf);
- }
-#ifdef CONFIG_HOTPLUG_CPU
- put_online_cpus();
-#endif
- free_percpu(chanb->buf);
- } else
- kfree(chanb->buf);
-free_cpumask:
- if (config->alloc == RING_BUFFER_ALLOC_PER_CPU)
- free_cpumask_var(chanb->cpumask);
- return -ENOMEM;
-}
-
-/**
- * channel_backend_unregister_notifiers - unregister notifiers
- * @chan: the channel
- *
- * Holds CPU hotplug.
- */
-void channel_backend_unregister_notifiers(struct channel_backend *chanb)
-{
- const struct lib_ring_buffer_config *config = chanb->config;
-
- if (config->alloc == RING_BUFFER_ALLOC_PER_CPU)
- unregister_hotcpu_notifier(&chanb->cpu_hp_notifier);
-}
-
-/**
- * channel_backend_free - destroy the channel
- * @chan: the channel
- *
- * Destroy all channel buffers and frees the channel.
- */
-void channel_backend_free(struct channel_backend *chanb)
-{
- const struct lib_ring_buffer_config *config = chanb->config;
- unsigned int i;
-
- if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
- for_each_possible_cpu(i) {
- struct lib_ring_buffer *buf = per_cpu_ptr(chanb->buf, i);
-
- if (!buf->backend.allocated)
- continue;
- lib_ring_buffer_free(buf);
- }
- free_cpumask_var(chanb->cpumask);
- free_percpu(chanb->buf);
- } else {
- struct lib_ring_buffer *buf = chanb->buf;
-
- CHAN_WARN_ON(chanb, !buf->backend.allocated);
- lib_ring_buffer_free(buf);
- kfree(buf);
- }
-}
-
-/**
- * lib_ring_buffer_write - write data to a ring_buffer buffer.
- * @bufb : buffer backend
- * @offset : offset within the buffer
- * @src : source address
- * @len : length to write
- * @pagecpy : page size copied so far
- */
-void _lib_ring_buffer_write(struct lib_ring_buffer_backend *bufb, size_t offset,
- const void *src, size_t len, ssize_t pagecpy)
-{
- struct channel_backend *chanb = &bufb->chan->backend;
- const struct lib_ring_buffer_config *config = chanb->config;
- size_t sbidx, index;
- struct lib_ring_buffer_backend_pages *rpages;
- unsigned long sb_bindex, id;
-
- do {
- len -= pagecpy;
- src += pagecpy;
- offset += pagecpy;
- sbidx = offset >> chanb->subbuf_size_order;
- index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
-
- /*
- * Underlying layer should never ask for writes across
- * subbuffers.
- */
- CHAN_WARN_ON(chanb, offset >= chanb->buf_size);
-
- pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK));
- id = bufb->buf_wsb[sbidx].id;
- sb_bindex = subbuffer_id_get_index(config, id);
- rpages = bufb->array[sb_bindex];
- CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
- && subbuffer_id_is_noref(config, id));
- lib_ring_buffer_do_copy(config,
- rpages->p[index].virt
- + (offset & ~PAGE_MASK),
- src, pagecpy);
- } while (unlikely(len != pagecpy));
-}
-EXPORT_SYMBOL_GPL(_lib_ring_buffer_write);
-
-/**
- * lib_ring_buffer_read - read data from ring_buffer_buffer.
- * @bufb : buffer backend
- * @offset : offset within the buffer
- * @dest : destination address
- * @len : length to copy to destination
- *
- * Should be protected by get_subbuf/put_subbuf.
- * Returns the length copied.
- */
-size_t lib_ring_buffer_read(struct lib_ring_buffer_backend *bufb, size_t offset,
- void *dest, size_t len)
-{
- struct channel_backend *chanb = &bufb->chan->backend;
- const struct lib_ring_buffer_config *config = chanb->config;
- size_t index;
- ssize_t pagecpy, orig_len;
- struct lib_ring_buffer_backend_pages *rpages;
- unsigned long sb_bindex, id;
-
- orig_len = len;
- offset &= chanb->buf_size - 1;
- index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
- if (unlikely(!len))
- return 0;
- for (;;) {
- pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK));
- id = bufb->buf_rsb.id;
- sb_bindex = subbuffer_id_get_index(config, id);
- rpages = bufb->array[sb_bindex];
- CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
- && subbuffer_id_is_noref(config, id));
- memcpy(dest, rpages->p[index].virt + (offset & ~PAGE_MASK),
- pagecpy);
- len -= pagecpy;
- if (likely(!len))
- break;
- dest += pagecpy;
- offset += pagecpy;
- index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
- /*
- * Underlying layer should never ask for reads across
- * subbuffers.
- */
- CHAN_WARN_ON(chanb, offset >= chanb->buf_size);
- }
- return orig_len;
-}
-EXPORT_SYMBOL_GPL(lib_ring_buffer_read);
-
-/**
- * __lib_ring_buffer_copy_to_user - read data from ring_buffer to userspace
- * @bufb : buffer backend
- * @offset : offset within the buffer
- * @dest : destination userspace address
- * @len : length to copy to destination
- *
- * Should be protected by get_subbuf/put_subbuf.
- * access_ok() must have been performed on dest addresses prior to call this
- * function.
- * Returns -EFAULT on error, 0 if ok.
- */
-int __lib_ring_buffer_copy_to_user(struct lib_ring_buffer_backend *bufb,
- size_t offset, void __user *dest, size_t len)
-{
- struct channel_backend *chanb = &bufb->chan->backend;
- const struct lib_ring_buffer_config *config = chanb->config;
- size_t index;
- ssize_t pagecpy, orig_len;
- struct lib_ring_buffer_backend_pages *rpages;
- unsigned long sb_bindex, id;
-
- orig_len = len;
- offset &= chanb->buf_size - 1;
- index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
- if (unlikely(!len))
- return 0;
- for (;;) {
- pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK));
- id = bufb->buf_rsb.id;
- sb_bindex = subbuffer_id_get_index(config, id);
- rpages = bufb->array[sb_bindex];
- CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
- && subbuffer_id_is_noref(config, id));
- if (__copy_to_user(dest,
- rpages->p[index].virt + (offset & ~PAGE_MASK),
- pagecpy))
- return -EFAULT;
- len -= pagecpy;
- if (likely(!len))
- break;
- dest += pagecpy;
- offset += pagecpy;
- index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
- /*
- * Underlying layer should never ask for reads across
- * subbuffers.
- */
- CHAN_WARN_ON(chanb, offset >= chanb->buf_size);
- }
- return 0;
-}
-EXPORT_SYMBOL_GPL(__lib_ring_buffer_copy_to_user);
-
-/**
- * lib_ring_buffer_read_cstr - read a C-style string from ring_buffer.
- * @bufb : buffer backend
- * @offset : offset within the buffer
- * @dest : destination address
- * @len : destination's length
- *
- * return string's length
- * Should be protected by get_subbuf/put_subbuf.
- */
-int lib_ring_buffer_read_cstr(struct lib_ring_buffer_backend *bufb, size_t offset,
- void *dest, size_t len)
-{
- struct channel_backend *chanb = &bufb->chan->backend;
- const struct lib_ring_buffer_config *config = chanb->config;
- size_t index;
- ssize_t pagecpy, pagelen, strpagelen, orig_offset;
- char *str;
- struct lib_ring_buffer_backend_pages *rpages;
- unsigned long sb_bindex, id;
-
- offset &= chanb->buf_size - 1;
- index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
- orig_offset = offset;
- for (;;) {
- id = bufb->buf_rsb.id;
- sb_bindex = subbuffer_id_get_index(config, id);
- rpages = bufb->array[sb_bindex];
- CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
- && subbuffer_id_is_noref(config, id));
- str = (char *)rpages->p[index].virt + (offset & ~PAGE_MASK);
- pagelen = PAGE_SIZE - (offset & ~PAGE_MASK);
- strpagelen = strnlen(str, pagelen);
- if (len) {
- pagecpy = min_t(size_t, len, strpagelen);
- if (dest) {
- memcpy(dest, str, pagecpy);
- dest += pagecpy;
- }
- len -= pagecpy;
- }
- offset += strpagelen;
- index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
- if (strpagelen < pagelen)
- break;
- /*
- * Underlying layer should never ask for reads across
- * subbuffers.
- */
- CHAN_WARN_ON(chanb, offset >= chanb->buf_size);
- }
- if (dest && len)
- ((char *)dest)[0] = 0;
- return offset - orig_offset;
-}
-EXPORT_SYMBOL_GPL(lib_ring_buffer_read_cstr);
-
-/**
- * lib_ring_buffer_read_get_page - Get a whole page to read from
- * @bufb : buffer backend
- * @offset : offset within the buffer
- * @virt : pointer to page address (output)
- *
- * Should be protected by get_subbuf/put_subbuf.
- * Returns the pointer to the page struct pointer.
- */
-struct page **lib_ring_buffer_read_get_page(struct lib_ring_buffer_backend *bufb,
- size_t offset, void ***virt)
-{
- size_t index;
- struct lib_ring_buffer_backend_pages *rpages;
- struct channel_backend *chanb = &bufb->chan->backend;
- const struct lib_ring_buffer_config *config = chanb->config;
- unsigned long sb_bindex, id;
-
- offset &= chanb->buf_size - 1;
- index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
- id = bufb->buf_rsb.id;
- sb_bindex = subbuffer_id_get_index(config, id);
- rpages = bufb->array[sb_bindex];
- CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
- && subbuffer_id_is_noref(config, id));
- *virt = &rpages->p[index].virt;
- return &rpages->p[index].page;
-}
-EXPORT_SYMBOL_GPL(lib_ring_buffer_read_get_page);
-
-/**
- * lib_ring_buffer_read_offset_address - get address of a buffer location
- * @bufb : buffer backend
- * @offset : offset within the buffer.
- *
- * Return the address where a given offset is located (for read).
- * 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 *lib_ring_buffer_read_offset_address(struct lib_ring_buffer_backend *bufb,
- size_t offset)
-{
- size_t index;
- struct lib_ring_buffer_backend_pages *rpages;
- struct channel_backend *chanb = &bufb->chan->backend;
- const struct lib_ring_buffer_config *config = chanb->config;
- unsigned long sb_bindex, id;
-
- offset &= chanb->buf_size - 1;
- index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
- id = bufb->buf_rsb.id;
- sb_bindex = subbuffer_id_get_index(config, id);
- rpages = bufb->array[sb_bindex];
- CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
- && subbuffer_id_is_noref(config, id));
- return rpages->p[index].virt + (offset & ~PAGE_MASK);
-}
-EXPORT_SYMBOL_GPL(lib_ring_buffer_read_offset_address);
-
-/**
- * lib_ring_buffer_offset_address - get address of a location within the buffer
- * @bufb : buffer backend
- * @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 always at the beginning of a page, it's safe to write directly to this
- * address, as long as the write is never bigger than a page size.
- */
-void *lib_ring_buffer_offset_address(struct lib_ring_buffer_backend *bufb,
- size_t offset)
-{
- size_t sbidx, index;
- struct lib_ring_buffer_backend_pages *rpages;
- struct channel_backend *chanb = &bufb->chan->backend;
- const struct lib_ring_buffer_config *config = chanb->config;
- unsigned long sb_bindex, id;
-
- offset &= chanb->buf_size - 1;
- sbidx = offset >> chanb->subbuf_size_order;
- index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
- id = bufb->buf_wsb[sbidx].id;
- sb_bindex = subbuffer_id_get_index(config, id);
- rpages = bufb->array[sb_bindex];
- CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
- && subbuffer_id_is_noref(config, id));
- return rpages->p[index].virt + (offset & ~PAGE_MASK);
-}
-EXPORT_SYMBOL_GPL(lib_ring_buffer_offset_address);
projects / lttng-ust.git / blobdiff