/*
* Public API and common code for kernel->userspace relay file support.
*
- * See Documentation/filesystems/relayfs.txt for an overview of relayfs.
+ * See Documentation/filesystems/relay.txt for an overview.
*
* Copyright (C) 2002-2005 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp
* Copyright (C) 1999-2005 - Karim Yaghmour (karim@opersys.com)
*
* 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.
*/
#include <linux/relay.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
+#include <linux/cpu.h>
+#include <linux/splice.h>
+
+/* list of open channels, for cpu hotplug */
+static DEFINE_MUTEX(relay_channels_mutex);
+static LIST_HEAD(relay_channels);
/*
* close() vm_op implementation for relay file mapping.
}
/*
- * nopage() vm_op implementation for relay file mapping.
+ * fault() vm_op implementation for relay file mapping.
*/
-static struct page *relay_buf_nopage(struct vm_area_struct *vma,
- unsigned long address,
- int *type)
+static int relay_buf_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct page *page;
struct rchan_buf *buf = vma->vm_private_data;
- unsigned long offset = address - vma->vm_start;
+ pgoff_t pgoff = vmf->pgoff;
- if (address > vma->vm_end)
- return NOPAGE_SIGBUS; /* Disallow mremap */
if (!buf)
- return NOPAGE_OOM;
+ return VM_FAULT_OOM;
- page = vmalloc_to_page(buf->start + offset);
+ page = vmalloc_to_page(buf->start + (pgoff << PAGE_SHIFT));
if (!page)
- return NOPAGE_OOM;
+ return VM_FAULT_SIGBUS;
get_page(page);
+ vmf->page = page;
- if (type)
- *type = VM_FAULT_MINOR;
-
- return page;
+ return 0;
}
/*
* vm_ops for relay file mappings.
*/
-static struct vm_operations_struct relay_file_mmap_ops = {
- .nopage = relay_buf_nopage,
+static const struct vm_operations_struct relay_file_mmap_ops = {
+ .fault = relay_buf_fault,
.close = relay_file_mmap_close,
};
+/*
+ * allocate an array of pointers of struct page
+ */
+static struct page **relay_alloc_page_array(unsigned int n_pages)
+{
+ struct page **array;
+ size_t pa_size = n_pages * sizeof(struct page *);
+
+ if (pa_size > PAGE_SIZE) {
+ array = vmalloc(pa_size);
+ if (array)
+ memset(array, 0, pa_size);
+ } else {
+ array = kzalloc(pa_size, GFP_KERNEL);
+ }
+ return array;
+}
+
+/*
+ * free an array of pointers of struct page
+ */
+static void relay_free_page_array(struct page **array)
+{
+ if (is_vmalloc_addr(array))
+ vfree(array);
+ else
+ kfree(array);
+}
+
/**
* relay_mmap_buf: - mmap channel buffer to process address space
* @buf: relay channel buffer
*
* Caller should already have grabbed mmap_sem.
*/
-int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma)
+static int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma)
{
unsigned long length = vma->vm_end - vma->vm_start;
struct file *filp = vma->vm_file;
return -EINVAL;
vma->vm_ops = &relay_file_mmap_ops;
+ vma->vm_flags |= VM_DONTEXPAND;
vma->vm_private_data = buf;
buf->chan->cb->buf_mapped(buf, filp);
*size = PAGE_ALIGN(*size);
n_pages = *size >> PAGE_SHIFT;
- buf->page_array = kcalloc(n_pages, sizeof(struct page *), GFP_KERNEL);
+ buf->page_array = relay_alloc_page_array(n_pages);
if (!buf->page_array)
return NULL;
buf->page_array[i] = alloc_page(GFP_KERNEL);
if (unlikely(!buf->page_array[i]))
goto depopulate;
+ set_page_private(buf->page_array[i], (unsigned long)buf);
}
mem = vmap(buf->page_array, n_pages, VM_MAP, PAGE_KERNEL);
if (!mem)
depopulate:
for (j = 0; j < i; j++)
__free_page(buf->page_array[j]);
- kfree(buf->page_array);
+ relay_free_page_array(buf->page_array);
return NULL;
}
*
* Returns channel buffer if successful, %NULL otherwise.
*/
-struct rchan_buf *relay_create_buf(struct rchan *chan)
+static struct rchan_buf *relay_create_buf(struct rchan *chan)
{
- struct rchan_buf *buf = kcalloc(1, sizeof(struct rchan_buf), GFP_KERNEL);
+ struct rchan_buf *buf = kzalloc(sizeof(struct rchan_buf), GFP_KERNEL);
if (!buf)
return NULL;
*
* Should only be called from kref_put().
*/
-void relay_destroy_channel(struct kref *kref)
+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
*/
-void relay_destroy_buf(struct rchan_buf *buf)
+static void relay_destroy_buf(struct rchan_buf *buf)
{
struct rchan *chan = buf->chan;
unsigned int i;
vunmap(buf->start);
for (i = 0; i < buf->page_count; i++)
__free_page(buf->page_array[i]);
- kfree(buf->page_array);
+ relay_free_page_array(buf->page_array);
}
+ chan->buf[buf->cpu] = NULL;
kfree(buf->padding);
kfree(buf);
kref_put(&chan->kref, relay_destroy_channel);
* rchan_buf_struct and the channel buffer. Should only be called from
* kref_put().
*/
-void relay_remove_buf(struct kref *kref)
+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);
*
* Returns 1 if the buffer is empty, 0 otherwise.
*/
-int relay_buf_empty(struct rchan_buf *buf)
+static int relay_buf_empty(struct rchan_buf *buf)
{
return (buf->subbufs_produced - buf->subbufs_consumed) ? 0 : 1;
}
-EXPORT_SYMBOL_GPL(relay_buf_empty);
/**
* relay_buf_full - boolean, is the channel buffer full?
/**
* wakeup_readers - wake up readers waiting on a channel
- * @private: the channel buffer
+ * @data: contains 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.
+ * This is the timer function used to defer reader waking.
*/
-static void wakeup_readers(struct work_struct *work)
+static void wakeup_readers(unsigned long data)
{
- struct rchan_buf *buf =
- container_of(work, struct rchan_buf, wake_readers.work);
+ struct rchan_buf *buf = (struct rchan_buf *)data;
wake_up_interruptible(&buf->read_wait);
}
* @buf: the channel buffer
* @init: 1 if this is a first-time initialization
*
- * See relay_reset for description of effect.
+ * See relay_reset() for description of effect.
*/
-static inline void __relay_reset(struct rchan_buf *buf, unsigned int init)
+static 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_DELAYED_WORK(&buf->wake_readers, NULL);
- } else {
- cancel_delayed_work(&buf->wake_readers);
- flush_scheduled_work();
- }
+ setup_timer(&buf->timer, wakeup_readers, (unsigned long)buf);
+ } else
+ del_timer_sync(&buf->timer);
buf->subbufs_produced = 0;
buf->subbufs_consumed = 0;
* 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
+ * 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];
+ if (chan->is_global && chan->buf[0]) {
+ __relay_reset(chan->buf[0], 0);
+ return;
}
+
+ mutex_lock(&relay_channels_mutex);
+ for_each_possible_cpu(i)
+ if (chan->buf[i])
+ __relay_reset(chan->buf[i], 0);
+ mutex_unlock(&relay_channels_mutex);
}
EXPORT_SYMBOL_GPL(relay_reset);
+static inline void relay_set_buf_dentry(struct rchan_buf *buf,
+ struct dentry *dentry)
+{
+ buf->dentry = dentry;
+ buf->dentry->d_inode->i_size = buf->early_bytes;
+}
+
+static struct dentry *relay_create_buf_file(struct rchan *chan,
+ struct rchan_buf *buf,
+ unsigned int cpu)
+{
+ struct dentry *dentry;
+ char *tmpname;
+
+ tmpname = kzalloc(NAME_MAX + 1, GFP_KERNEL);
+ if (!tmpname)
+ return NULL;
+ snprintf(tmpname, NAME_MAX, "%s%d", chan->base_filename, cpu);
+
+ /* Create file in fs */
+ dentry = chan->cb->create_buf_file(tmpname, chan->parent,
+ S_IRUSR, buf,
+ &chan->is_global);
+
+ kfree(tmpname);
+
+ return dentry;
+}
+
/*
* relay_open_buf - create a new relay channel buffer
*
- * Internal - used by relay_open().
+ * used by relay_open() and CPU hotplug.
*/
-static struct rchan_buf *relay_open_buf(struct rchan *chan,
- const char *filename,
- struct dentry *parent,
- int *is_global)
+static struct rchan_buf *relay_open_buf(struct rchan *chan, unsigned int cpu)
{
- struct rchan_buf *buf;
+ struct rchan_buf *buf = NULL;
struct dentry *dentry;
- if (*is_global)
+ if (chan->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;
+ if (chan->has_base_filename) {
+ dentry = relay_create_buf_file(chan, buf, cpu);
+ if (!dentry)
+ goto free_buf;
+ relay_set_buf_dentry(buf, dentry);
}
- buf->dentry = dentry;
- __relay_reset(buf, 1);
+ buf->cpu = cpu;
+ __relay_reset(buf, 1);
+
+ if(chan->is_global) {
+ chan->buf[0] = buf;
+ buf->cpu = 0;
+ }
return buf;
+
+free_buf:
+ relay_destroy_buf(buf);
+ return NULL;
}
/**
* 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)
+static void relay_close_buf(struct rchan_buf *buf)
{
buf->finalized = 1;
- cancel_delayed_work(&buf->wake_readers);
- flush_scheduled_work();
+ del_timer_sync(&buf->timer);
kref_put(&buf->kref, relay_remove_buf);
}
-static inline void setup_callbacks(struct rchan *chan,
+static void setup_callbacks(struct rchan *chan,
struct rchan_callbacks *cb)
{
if (!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)
+ */
+static int __cpuinit relay_hotcpu_callback(struct notifier_block *nb,
+ unsigned long action,
+ void *hcpu)
+{
+ unsigned int hotcpu = (unsigned long)hcpu;
+ struct rchan *chan;
+
+ switch(action) {
+ case CPU_UP_PREPARE:
+ case CPU_UP_PREPARE_FROZEN:
+ mutex_lock(&relay_channels_mutex);
+ list_for_each_entry(chan, &relay_channels, list) {
+ if (chan->buf[hotcpu])
+ continue;
+ chan->buf[hotcpu] = relay_open_buf(chan, hotcpu);
+ if(!chan->buf[hotcpu]) {
+ printk(KERN_ERR
+ "relay_hotcpu_callback: cpu %d buffer "
+ "creation failed\n", hotcpu);
+ mutex_unlock(&relay_channels_mutex);
+ return notifier_from_errno(-ENOMEM);
+ }
+ }
+ mutex_unlock(&relay_channels_mutex);
+ break;
+ case CPU_DEAD:
+ case CPU_DEAD_FROZEN:
+ /* No need to flush the cpu : will be flushed upon
+ * final relay_flush() call. */
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+/**
* relay_open - create a new relay channel
- * @base_filename: base name of files to create
- * @parent: dentry of parent directory, %NULL for root directory
+ * @base_filename: base name of files to create, %NULL for buffering only
+ * @parent: dentry of parent directory, %NULL for root directory or buffer
* @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.
+ * 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)
+ struct rchan_callbacks *cb,
+ void *private_data)
{
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);
+ chan = kzalloc(sizeof(struct rchan), GFP_KERNEL);
if (!chan)
return NULL;
chan->n_subbufs = n_subbufs;
chan->subbuf_size = subbuf_size;
chan->alloc_size = FIX_SIZE(subbuf_size * n_subbufs);
+ chan->parent = parent;
+ chan->private_data = private_data;
+ if (base_filename) {
+ chan->has_base_filename = 1;
+ strlcpy(chan->base_filename, base_filename, NAME_MAX);
+ }
setup_callbacks(chan, cb);
kref_init(&chan->kref);
- tmpname = kmalloc(NAME_MAX + 1, GFP_KERNEL);
- if (!tmpname)
- goto free_chan;
-
+ mutex_lock(&relay_channels_mutex);
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] = relay_open_buf(chan, i);
if (!chan->buf[i])
goto free_bufs;
-
- chan->buf[i]->cpu = i;
}
+ list_add(&chan->list, &relay_channels);
+ mutex_unlock(&relay_channels_mutex);
- 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;
+ for_each_possible_cpu(i) {
+ if (chan->buf[i])
+ relay_close_buf(chan->buf[i]);
}
- kfree(tmpname);
-free_chan:
kref_put(&chan->kref, relay_destroy_channel);
+ mutex_unlock(&relay_channels_mutex);
return NULL;
}
EXPORT_SYMBOL_GPL(relay_open);
+struct rchan_percpu_buf_dispatcher {
+ struct rchan_buf *buf;
+ 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.
+ * Useful to do early tracing in kernel, before VFS is up, for example.
+ */
+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_percpu_buf_dispatcher disp;
+
+ if (!chan || !base_filename)
+ return -EINVAL;
+
+ strlcpy(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;
+ 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) {
+ if (unlikely(!chan->buf[i])) {
+ WARN_ONCE(1, KERN_ERR "CPU has no buffer!\n");
+ err = -EINVAL;
+ break;
+ }
+
+ dentry = relay_create_buf_file(chan, chan->buf[i], i);
+ if (unlikely(!dentry)) {
+ err = -EINVAL;
+ break;
+ }
+
+ if (curr_cpu == i) {
+ local_irq_save(flags);
+ relay_set_buf_dentry(chan->buf[i], dentry);
+ local_irq_restore(flags);
+ } else {
+ disp.buf = chan->buf[i];
+ 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;
+}
+
/**
* relay_switch_subbuf - switch to a new sub-buffer
* @buf: channel buffer
old_subbuf = buf->subbufs_produced % buf->chan->n_subbufs;
buf->padding[old_subbuf] = buf->prev_padding;
buf->subbufs_produced++;
- buf->dentry->d_inode->i_size += buf->chan->subbuf_size -
- buf->padding[old_subbuf];
+ if (buf->dentry)
+ buf->dentry->d_inode->i_size +=
+ buf->chan->subbuf_size -
+ buf->padding[old_subbuf];
+ else
+ buf->early_bytes += buf->chan->subbuf_size -
+ buf->padding[old_subbuf];
smp_mb();
- if (waitqueue_active(&buf->read_wait)) {
- PREPARE_DELAYED_WORK(&buf->wake_readers,
- wakeup_readers);
- schedule_delayed_work(&buf->wake_readers, 1);
- }
+ if (waitqueue_active(&buf->read_wait))
+ /*
+ * Calling wake_up_interruptible() from here
+ * will deadlock if we happen to be logging
+ * from the scheduler (trying to re-grab
+ * rq->lock), so defer it.
+ */
+ mod_timer(&buf->timer, jiffies + 1);
}
old = buf->data;
* 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
+ * NOTE. Kernel clients don't need to call this function if the channel
* mode is 'overwrite'.
*/
void relay_subbufs_consumed(struct rchan *chan,
if (!chan)
return;
- if (cpu >= NR_CPUS || !chan->buf[cpu])
+ if (cpu >= NR_CPUS || !chan->buf[cpu] ||
+ subbufs_consumed > chan->n_subbufs)
return;
buf = chan->buf[cpu];
- buf->subbufs_consumed += subbufs_consumed;
- if (buf->subbufs_consumed > buf->subbufs_produced)
+ if (subbufs_consumed > buf->subbufs_produced - buf->subbufs_consumed)
buf->subbufs_consumed = buf->subbufs_produced;
+ else
+ buf->subbufs_consumed += subbufs_consumed;
}
EXPORT_SYMBOL_GPL(relay_subbufs_consumed);
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];
- }
+ mutex_lock(&relay_channels_mutex);
+ if (chan->is_global && chan->buf[0])
+ relay_close_buf(chan->buf[0]);
+ else
+ for_each_possible_cpu(i)
+ if (chan->buf[i])
+ relay_close_buf(chan->buf[i]);
if (chan->last_toobig)
printk(KERN_WARNING "relay: one or more items not logged "
"[item size (%Zd) > sub-buffer size (%Zd)]\n",
chan->last_toobig, chan->subbuf_size);
+ list_del(&chan->list);
kref_put(&chan->kref, relay_destroy_channel);
+ mutex_unlock(&relay_channels_mutex);
}
EXPORT_SYMBOL_GPL(relay_close);
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];
+ if (chan->is_global && chan->buf[0]) {
+ relay_switch_subbuf(chan->buf[0], 0);
+ return;
}
+
+ mutex_lock(&relay_channels_mutex);
+ for_each_possible_cpu(i)
+ if (chan->buf[i])
+ relay_switch_subbuf(chan->buf[i], 0);
+ mutex_unlock(&relay_channels_mutex);
}
EXPORT_SYMBOL_GPL(relay_flush);
kref_get(&buf->kref);
filp->private_data = buf;
- return 0;
+ return nonseekable_open(inode, filp);
}
/**
* @filp: the file
* @vma: the vma describing what to map
*
- * Calls upon relay_mmap_buf to map the file into user space.
+ * Calls upon relay_mmap_buf() to map the file into user space.
*/
static int relay_file_mmap(struct file *filp, struct vm_area_struct *vma)
{
size_t n_subbufs = buf->chan->n_subbufs;
size_t read_subbuf;
+ if (buf->subbufs_produced == buf->subbufs_consumed &&
+ buf->offset == buf->bytes_consumed)
+ return;
+
if (buf->bytes_consumed + bytes_consumed > subbuf_size) {
relay_subbufs_consumed(buf->chan, buf->cpu, 1);
buf->bytes_consumed = 0;
}
buf->bytes_consumed += bytes_consumed;
- read_subbuf = read_pos / buf->chan->subbuf_size;
+ if (!read_pos)
+ read_subbuf = buf->subbufs_consumed % n_subbufs;
+ else
+ read_subbuf = read_pos / buf->chan->subbuf_size;
if (buf->bytes_consumed + buf->padding[read_subbuf] == subbuf_size) {
if ((read_subbuf == buf->subbufs_produced % n_subbufs) &&
(buf->offset == subbuf_size))
relay_file_read_consume(buf, read_pos, 0);
+ consumed = buf->subbufs_consumed;
+
if (unlikely(buf->offset > subbuf_size)) {
if (produced == consumed)
return 0;
}
if (unlikely(produced - consumed >= n_subbufs)) {
- consumed = (produced / n_subbufs) * n_subbufs;
+ consumed = produced - n_subbufs + 1;
buf->subbufs_consumed = consumed;
+ buf->bytes_consumed = 0;
}
-
+
produced = (produced % n_subbufs) * subbuf_size + buf->offset;
consumed = (consumed % n_subbufs) * subbuf_size + buf->bytes_consumed;
if (consumed > produced)
produced += n_subbufs * subbuf_size;
-
- if (consumed == produced)
+
+ if (consumed == produced) {
+ if (buf->offset == subbuf_size &&
+ buf->subbufs_produced > buf->subbufs_consumed)
+ return 1;
return 0;
+ }
return 1;
}
* @read_pos: file read position
* @buf: relay channel buffer
*
- * If the read_pos is in the middle of padding, return the
+ * If the @read_pos is in the middle of padding, return the
* position of the first actually available byte, otherwise
* return the original value.
*/
size_t read_subbuf, padding, padding_start, padding_end;
size_t subbuf_size = buf->chan->subbuf_size;
size_t n_subbufs = buf->chan->n_subbufs;
+ size_t consumed = buf->subbufs_consumed % n_subbufs;
+ if (!read_pos)
+ read_pos = consumed * subbuf_size + buf->bytes_consumed;
read_subbuf = read_pos / subbuf_size;
padding = buf->padding[read_subbuf];
padding_start = (read_subbuf + 1) * subbuf_size - padding;
return ret;
}
-/*
- * subbuf_send_actor - send up to one subbuf's worth of data
- */
-static int subbuf_send_actor(size_t read_start,
- struct rchan_buf *buf,
- size_t avail,
- read_descriptor_t *desc,
- read_actor_t actor)
-{
- unsigned long pidx, poff;
- unsigned int subbuf_pages;
- int ret = 0;
-
- subbuf_pages = buf->chan->alloc_size >> PAGE_SHIFT;
- pidx = (read_start / PAGE_SIZE) % subbuf_pages;
- poff = read_start & ~PAGE_MASK;
- while (avail) {
- struct page *p = buf->page_array[pidx];
- unsigned int len;
-
- len = PAGE_SIZE - poff;
- if (len > avail)
- len = avail;
-
- len = actor(desc, p, poff, len);
- if (desc->error)
- break;
-
- avail -= len;
- ret += len;
- poff = 0;
- pidx = (pidx + 1) % subbuf_pages;
- }
-
- return ret;
-}
-
typedef int (*subbuf_actor_t) (size_t read_start,
struct rchan_buf *buf,
size_t avail,
/*
* relay_file_read_subbufs - read count bytes, bridging subbuf boundaries
*/
-static inline ssize_t relay_file_read_subbufs(struct file *filp,
- loff_t *ppos,
- subbuf_actor_t subbuf_actor,
- read_actor_t actor,
- read_descriptor_t *desc)
+static ssize_t relay_file_read_subbufs(struct file *filp, loff_t *ppos,
+ subbuf_actor_t subbuf_actor,
+ read_actor_t actor,
+ read_descriptor_t *desc)
{
struct rchan_buf *buf = filp->private_data;
size_t read_start, avail;
if (!desc->count)
return 0;
- mutex_lock(&filp->f_dentry->d_inode->i_mutex);
+ mutex_lock(&filp->f_path.dentry->d_inode->i_mutex);
do {
if (!relay_file_read_avail(buf, *ppos))
break;
*ppos = relay_file_read_end_pos(buf, read_start, ret);
}
} while (desc->count && ret);
- mutex_unlock(&filp->f_dentry->d_inode->i_mutex);
+ mutex_unlock(&filp->f_path.dentry->d_inode->i_mutex);
return desc->written;
}
NULL, &desc);
}
-static ssize_t relay_file_sendfile(struct file *filp,
- loff_t *ppos,
- size_t count,
- read_actor_t actor,
- void *target)
+static void relay_consume_bytes(struct rchan_buf *rbuf, int bytes_consumed)
{
- read_descriptor_t desc;
- desc.written = 0;
- desc.count = count;
- desc.arg.data = target;
- desc.error = 0;
- return relay_file_read_subbufs(filp, ppos, subbuf_send_actor,
- actor, &desc);
+ rbuf->bytes_consumed += bytes_consumed;
+
+ if (rbuf->bytes_consumed >= rbuf->chan->subbuf_size) {
+ relay_subbufs_consumed(rbuf->chan, rbuf->cpu, 1);
+ rbuf->bytes_consumed %= rbuf->chan->subbuf_size;
+ }
+}
+
+static void relay_pipe_buf_release(struct pipe_inode_info *pipe,
+ struct pipe_buffer *buf)
+{
+ struct rchan_buf *rbuf;
+
+ rbuf = (struct rchan_buf *)page_private(buf->page);
+ relay_consume_bytes(rbuf, buf->private);
+}
+
+static const struct pipe_buf_operations relay_pipe_buf_ops = {
+ .can_merge = 0,
+ .map = generic_pipe_buf_map,
+ .unmap = generic_pipe_buf_unmap,
+ .confirm = generic_pipe_buf_confirm,
+ .release = relay_pipe_buf_release,
+ .steal = generic_pipe_buf_steal,
+ .get = generic_pipe_buf_get,
+};
+
+static void relay_page_release(struct splice_pipe_desc *spd, unsigned int i)
+{
+}
+
+/*
+ * subbuf_splice_actor - splice up to one subbuf's worth of data
+ */
+static ssize_t subbuf_splice_actor(struct file *in,
+ loff_t *ppos,
+ struct pipe_inode_info *pipe,
+ size_t len,
+ unsigned int flags,
+ int *nonpad_ret)
+{
+ unsigned int pidx, poff, total_len, subbuf_pages, nr_pages;
+ struct rchan_buf *rbuf = in->private_data;
+ unsigned int subbuf_size = rbuf->chan->subbuf_size;
+ uint64_t pos = (uint64_t) *ppos;
+ uint32_t alloc_size = (uint32_t) rbuf->chan->alloc_size;
+ size_t read_start = (size_t) do_div(pos, alloc_size);
+ size_t read_subbuf = read_start / subbuf_size;
+ size_t padding = rbuf->padding[read_subbuf];
+ size_t nonpad_end = read_subbuf * subbuf_size + subbuf_size - padding;
+ struct page *pages[PIPE_DEF_BUFFERS];
+ struct partial_page partial[PIPE_DEF_BUFFERS];
+ struct splice_pipe_desc spd = {
+ .pages = pages,
+ .nr_pages = 0,
+ .partial = partial,
+ .flags = flags,
+ .ops = &relay_pipe_buf_ops,
+ .spd_release = relay_page_release,
+ };
+ ssize_t ret;
+
+ if (rbuf->subbufs_produced == rbuf->subbufs_consumed)
+ return 0;
+ if (splice_grow_spd(pipe, &spd))
+ return -ENOMEM;
+
+ /*
+ * Adjust read len, if longer than what is available
+ */
+ if (len > (subbuf_size - read_start % subbuf_size))
+ len = subbuf_size - read_start % subbuf_size;
+
+ subbuf_pages = rbuf->chan->alloc_size >> PAGE_SHIFT;
+ pidx = (read_start / PAGE_SIZE) % subbuf_pages;
+ poff = read_start & ~PAGE_MASK;
+ nr_pages = min_t(unsigned int, subbuf_pages, pipe->buffers);
+
+ for (total_len = 0; spd.nr_pages < nr_pages; spd.nr_pages++) {
+ unsigned int this_len, this_end, private;
+ unsigned int cur_pos = read_start + total_len;
+
+ if (!len)
+ break;
+
+ this_len = min_t(unsigned long, len, PAGE_SIZE - poff);
+ private = this_len;
+
+ spd.pages[spd.nr_pages] = rbuf->page_array[pidx];
+ spd.partial[spd.nr_pages].offset = poff;
+
+ this_end = cur_pos + this_len;
+ if (this_end >= nonpad_end) {
+ this_len = nonpad_end - cur_pos;
+ private = this_len + padding;
+ }
+ spd.partial[spd.nr_pages].len = this_len;
+ spd.partial[spd.nr_pages].private = private;
+
+ len -= this_len;
+ total_len += this_len;
+ poff = 0;
+ pidx = (pidx + 1) % subbuf_pages;
+
+ if (this_end >= nonpad_end) {
+ spd.nr_pages++;
+ break;
+ }
+ }
+
+ ret = 0;
+ if (!spd.nr_pages)
+ goto out;
+
+ ret = *nonpad_ret = splice_to_pipe(pipe, &spd);
+ if (ret < 0 || ret < total_len)
+ goto out;
+
+ if (read_start + ret == nonpad_end)
+ ret += padding;
+
+out:
+ splice_shrink_spd(pipe, &spd);
+ return ret;
+}
+
+static ssize_t relay_file_splice_read(struct file *in,
+ loff_t *ppos,
+ struct pipe_inode_info *pipe,
+ size_t len,
+ unsigned int flags)
+{
+ ssize_t spliced;
+ int ret;
+ int nonpad_ret = 0;
+
+ ret = 0;
+ spliced = 0;
+
+ while (len && !spliced) {
+ ret = subbuf_splice_actor(in, ppos, pipe, len, flags, &nonpad_ret);
+ if (ret < 0)
+ break;
+ else if (!ret) {
+ if (flags & SPLICE_F_NONBLOCK)
+ ret = -EAGAIN;
+ break;
+ }
+
+ *ppos += ret;
+ if (ret > len)
+ len = 0;
+ else
+ len -= ret;
+ spliced += nonpad_ret;
+ nonpad_ret = 0;
+ }
+
+ if (spliced)
+ return spliced;
+
+ return ret;
}
-struct file_operations relay_file_operations = {
+const struct file_operations relay_file_operations = {
.open = relay_file_open,
.poll = relay_file_poll,
.mmap = relay_file_mmap,
.read = relay_file_read,
.llseek = no_llseek,
.release = relay_file_release,
- .sendfile = relay_file_sendfile,
+ .splice_read = relay_file_splice_read,
};
EXPORT_SYMBOL_GPL(relay_file_operations);
+
+static __init int relay_init(void)
+{
+
+ hotcpu_notifier(relay_hotcpu_callback, 0);
+ return 0;
+}
+
+early_initcall(relay_init);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff