#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/cpu.h>
+#include <linux/pipe_fs_i.h>
/* list of open channels, for cpu hotplug */
static DEFINE_MUTEX(relay_channels_mutex);
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)
/**
* wakeup_readers - wake up readers waiting on a channel
- * @work: work struct that contains the 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);
}
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;
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);
}
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])
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;
buf->dentry->d_inode->i_size += 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;
}
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))
}
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;
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,
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_pipe_buf_release(struct pipe_inode_info *pipe,
+ struct pipe_buffer *buf)
{
- 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);
+ struct rchan_buf *rbuf;
+
+ rbuf = (struct rchan_buf *)page_private(buf->page);
+
+ rbuf->bytes_consumed += PAGE_SIZE;
+
+ if (rbuf->bytes_consumed == rbuf->chan->subbuf_size) {
+ relay_subbufs_consumed(rbuf->chan, rbuf->cpu, 1);
+ rbuf->bytes_consumed = 0;
+ }
+}
+
+static struct pipe_buf_operations relay_pipe_buf_ops = {
+ .can_merge = 0,
+ .map = generic_pipe_buf_map,
+ .unmap = generic_pipe_buf_unmap,
+ .pin = generic_pipe_buf_pin,
+ .release = relay_pipe_buf_release,
+ .steal = generic_pipe_buf_steal,
+ .get = generic_pipe_buf_get,
+};
+
+/**
+ * subbuf_splice_actor - splice up to one subbuf's worth of data
+ */
+static int 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;
+ unsigned int subbuf_pages;
+ int ret = 0;
+ int do_wakeup = 0;
+ struct rchan_buf *rbuf = in->private_data;
+ unsigned int subbuf_size = rbuf->chan->subbuf_size;
+ size_t read_start = ((size_t)*ppos) % rbuf->chan->alloc_size;
+ size_t avail = subbuf_size - read_start % subbuf_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;
+
+ if (rbuf->subbufs_produced == rbuf->subbufs_consumed)
+ return 0;
+
+ if (len > avail)
+ len = avail;
+
+ if (pipe->inode)
+ mutex_lock(&pipe->inode->i_mutex);
+
+ subbuf_pages = rbuf->chan->alloc_size >> PAGE_SHIFT;
+ pidx = (read_start / PAGE_SIZE) % subbuf_pages;
+ poff = read_start & ~PAGE_MASK;
+
+ for (;;) {
+ unsigned int this_len;
+ unsigned int this_end;
+ int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1);
+ struct pipe_buffer *buf = pipe->bufs + newbuf;
+
+ if (!pipe->readers) {
+ send_sig(SIGPIPE, current, 0);
+ if (!ret)
+ ret = -EPIPE;
+ break;
+ }
+
+ if (pipe->nrbufs < PIPE_BUFFERS) {
+ this_len = PAGE_SIZE - poff;
+ if (this_len > avail)
+ this_len = avail;
+
+ buf->page = rbuf->page_array[pidx];
+ buf->offset = poff;
+ this_end = read_start + ret + this_len;
+ if (this_end > nonpad_end) {
+ if (read_start + ret >= nonpad_end)
+ buf->len = 0;
+ else
+ buf->len = nonpad_end - (read_start + ret);
+ } else
+ buf->len = this_len;
+
+ *nonpad_ret += buf->len;
+
+ buf->ops = &relay_pipe_buf_ops;
+ pipe->nrbufs++;
+
+ avail -= this_len;
+ ret += this_len;
+ poff = 0;
+ pidx = (pidx + 1) % subbuf_pages;
+
+ if (pipe->inode)
+ do_wakeup = 1;
+
+ if (!avail)
+ break;
+
+ if (pipe->nrbufs < PIPE_BUFFERS)
+ continue;
+
+ break;
+ }
+
+ if (flags & SPLICE_F_NONBLOCK) {
+ if (!ret)
+ ret = -EAGAIN;
+ break;
+ }
+
+ if (signal_pending(current)) {
+ if (!ret)
+ ret = -ERESTARTSYS;
+ break;
+ }
+
+ if (do_wakeup) {
+ smp_mb();
+ if (waitqueue_active(&pipe->wait))
+ wake_up_interruptible_sync(&pipe->wait);
+ kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
+ do_wakeup = 0;
+ }
+
+ pipe->waiting_writers++;
+ pipe_wait(pipe);
+ pipe->waiting_writers--;
+ }
+
+ if (pipe->inode)
+ mutex_unlock(&pipe->inode->i_mutex);
+
+ if (do_wakeup) {
+ smp_mb();
+ if (waitqueue_active(&pipe->wait))
+ wake_up_interruptible(&pipe->wait);
+ kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
+ }
+
+ 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) {
+ ret = subbuf_splice_actor(in, ppos, pipe, len, flags, &nonpad_ret);
+ if (ret < 0)
+ break;
+ else if (!ret) {
+ break;
+ if (spliced)
+ break;
+ 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;
}
const struct file_operations relay_file_operations = {
.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);