splice: relay support
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>wifi-calibration
Tom Zanussi
Jens Axboe
parent
cf8208d0ea
commit
ebf9909343
241
kernel/relay.c
241
kernel/relay.c
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@ -21,6 +21,7 @@
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#include <linux/vmalloc.h>
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#include <linux/mm.h>
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#include <linux/cpu.h>
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#include <linux/pipe_fs_i.h>
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/* list of open channels, for cpu hotplug */
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static DEFINE_MUTEX(relay_channels_mutex);
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@ -121,6 +122,7 @@ static void *relay_alloc_buf(struct rchan_buf *buf, size_t *size)
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buf->page_array[i] = alloc_page(GFP_KERNEL);
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if (unlikely(!buf->page_array[i]))
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goto depopulate;
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set_page_private(buf->page_array[i], (unsigned long)buf);
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}
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mem = vmap(buf->page_array, n_pages, VM_MAP, PAGE_KERNEL);
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if (!mem)
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@ -970,43 +972,6 @@ static int subbuf_read_actor(size_t read_start,
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return ret;
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}
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/*
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* subbuf_send_actor - send up to one subbuf's worth of data
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*/
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static int subbuf_send_actor(size_t read_start,
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struct rchan_buf *buf,
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size_t avail,
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read_descriptor_t *desc,
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read_actor_t actor)
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{
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unsigned long pidx, poff;
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unsigned int subbuf_pages;
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int ret = 0;
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subbuf_pages = buf->chan->alloc_size >> PAGE_SHIFT;
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pidx = (read_start / PAGE_SIZE) % subbuf_pages;
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poff = read_start & ~PAGE_MASK;
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while (avail) {
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struct page *p = buf->page_array[pidx];
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unsigned int len;
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len = PAGE_SIZE - poff;
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if (len > avail)
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len = avail;
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len = actor(desc, p, poff, len);
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if (desc->error)
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break;
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avail -= len;
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ret += len;
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poff = 0;
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pidx = (pidx + 1) % subbuf_pages;
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}
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return ret;
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}
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typedef int (*subbuf_actor_t) (size_t read_start,
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struct rchan_buf *buf,
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size_t avail,
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@ -1067,19 +1032,195 @@ static ssize_t relay_file_read(struct file *filp,
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NULL, &desc);
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}
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static ssize_t relay_file_sendfile(struct file *filp,
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loff_t *ppos,
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size_t count,
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read_actor_t actor,
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void *target)
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static void relay_pipe_buf_release(struct pipe_inode_info *pipe,
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struct pipe_buffer *buf)
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{
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read_descriptor_t desc;
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desc.written = 0;
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desc.count = count;
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desc.arg.data = target;
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desc.error = 0;
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return relay_file_read_subbufs(filp, ppos, subbuf_send_actor,
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actor, &desc);
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struct rchan_buf *rbuf;
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rbuf = (struct rchan_buf *)page_private(buf->page);
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rbuf->bytes_consumed += PAGE_SIZE;
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if (rbuf->bytes_consumed == rbuf->chan->subbuf_size) {
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relay_subbufs_consumed(rbuf->chan, rbuf->cpu, 1);
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rbuf->bytes_consumed = 0;
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}
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}
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static struct pipe_buf_operations relay_pipe_buf_ops = {
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.can_merge = 0,
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.map = generic_pipe_buf_map,
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.unmap = generic_pipe_buf_unmap,
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.pin = generic_pipe_buf_pin,
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.release = relay_pipe_buf_release,
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.steal = generic_pipe_buf_steal,
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.get = generic_pipe_buf_get,
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};
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/**
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* subbuf_splice_actor - splice up to one subbuf's worth of data
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*/
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static int subbuf_splice_actor(struct file *in,
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loff_t *ppos,
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struct pipe_inode_info *pipe,
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size_t len,
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unsigned int flags,
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int *nonpad_ret)
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{
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unsigned int pidx, poff;
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unsigned int subbuf_pages;
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int ret = 0;
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int do_wakeup = 0;
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struct rchan_buf *rbuf = in->private_data;
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unsigned int subbuf_size = rbuf->chan->subbuf_size;
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size_t read_start = ((size_t)*ppos) % rbuf->chan->alloc_size;
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size_t avail = subbuf_size - read_start % subbuf_size;
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size_t read_subbuf = read_start / subbuf_size;
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size_t padding = rbuf->padding[read_subbuf];
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size_t nonpad_end = read_subbuf * subbuf_size + subbuf_size - padding;
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if (rbuf->subbufs_produced == rbuf->subbufs_consumed)
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return 0;
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if (len > avail)
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len = avail;
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if (pipe->inode)
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mutex_lock(&pipe->inode->i_mutex);
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subbuf_pages = rbuf->chan->alloc_size >> PAGE_SHIFT;
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pidx = (read_start / PAGE_SIZE) % subbuf_pages;
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poff = read_start & ~PAGE_MASK;
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for (;;) {
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unsigned int this_len;
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unsigned int this_end;
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int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1);
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struct pipe_buffer *buf = pipe->bufs + newbuf;
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if (!pipe->readers) {
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send_sig(SIGPIPE, current, 0);
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if (!ret)
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ret = -EPIPE;
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break;
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}
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if (pipe->nrbufs < PIPE_BUFFERS) {
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this_len = PAGE_SIZE - poff;
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if (this_len > avail)
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this_len = avail;
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buf->page = rbuf->page_array[pidx];
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buf->offset = poff;
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this_end = read_start + ret + this_len;
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if (this_end > nonpad_end) {
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if (read_start + ret >= nonpad_end)
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buf->len = 0;
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else
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buf->len = nonpad_end - (read_start + ret);
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} else
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buf->len = this_len;
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*nonpad_ret += buf->len;
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buf->ops = &relay_pipe_buf_ops;
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pipe->nrbufs++;
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avail -= this_len;
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ret += this_len;
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poff = 0;
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pidx = (pidx + 1) % subbuf_pages;
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if (pipe->inode)
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do_wakeup = 1;
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if (!avail)
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break;
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if (pipe->nrbufs < PIPE_BUFFERS)
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continue;
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break;
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}
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if (flags & SPLICE_F_NONBLOCK) {
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if (!ret)
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ret = -EAGAIN;
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break;
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}
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if (signal_pending(current)) {
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if (!ret)
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ret = -ERESTARTSYS;
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break;
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}
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if (do_wakeup) {
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smp_mb();
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if (waitqueue_active(&pipe->wait))
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wake_up_interruptible_sync(&pipe->wait);
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kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
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do_wakeup = 0;
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}
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pipe->waiting_writers++;
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pipe_wait(pipe);
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pipe->waiting_writers--;
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}
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if (pipe->inode)
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mutex_unlock(&pipe->inode->i_mutex);
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if (do_wakeup) {
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smp_mb();
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if (waitqueue_active(&pipe->wait))
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wake_up_interruptible(&pipe->wait);
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kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
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}
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return ret;
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}
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static ssize_t relay_file_splice_read(struct file *in,
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loff_t *ppos,
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struct pipe_inode_info *pipe,
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size_t len,
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unsigned int flags)
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{
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ssize_t spliced;
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int ret;
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int nonpad_ret = 0;
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ret = 0;
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spliced = 0;
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while (len) {
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ret = subbuf_splice_actor(in, ppos, pipe, len, flags, &nonpad_ret);
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if (ret < 0)
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break;
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else if (!ret) {
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break;
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if (spliced)
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break;
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if (flags & SPLICE_F_NONBLOCK) {
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ret = -EAGAIN;
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break;
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}
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}
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*ppos += ret;
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if (ret > len)
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len = 0;
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else
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len -= ret;
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spliced += nonpad_ret;
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nonpad_ret = 0;
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}
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if (spliced)
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return spliced;
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return ret;
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}
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const struct file_operations relay_file_operations = {
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@ -1089,7 +1230,7 @@ const struct file_operations relay_file_operations = {
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.read = relay_file_read,
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.llseek = no_llseek,
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.release = relay_file_release,
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.sendfile = relay_file_sendfile,
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.splice_read = relay_file_splice_read,
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};
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EXPORT_SYMBOL_GPL(relay_file_operations);
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