Commit ebf99093 authored by Tom Zanussi's avatar Tom Zanussi Committed by Jens Axboe

splice: relay support

Signed-off-by: 's avatarJens Axboe <jens.axboe@oracle.com>
parent cf8208d0
......@@ -21,6 +21,7 @@
#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);
......@@ -121,6 +122,7 @@ static void *relay_alloc_buf(struct rchan_buf *buf, size_t *size)
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)
......@@ -970,43 +972,6 @@ static int subbuf_read_actor(size_t read_start,
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,
......@@ -1067,19 +1032,195 @@ static ssize_t relay_file_read(struct file *filp,
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 = {
......@@ -1089,7 +1230,7 @@ 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);
......
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