Commit 221415d7 authored by Jens Axboe's avatar Jens Axboe

[PATCH] relay: add sendfile() support

Signed-off-by: 's avatarJens Axboe <axboe@suse.de>
parent b86ff981
......@@ -95,15 +95,16 @@ int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma)
* @buf: the buffer struct
* @size: total size of the buffer
*
* Returns a pointer to the resulting buffer, NULL if unsuccessful
* Returns a pointer to the resulting buffer, NULL if unsuccessful. The
* passed in size will get page aligned, if it isn't already.
*/
static void *relay_alloc_buf(struct rchan_buf *buf, unsigned long size)
static void *relay_alloc_buf(struct rchan_buf *buf, size_t *size)
{
void *mem;
unsigned int i, j, n_pages;
size = PAGE_ALIGN(size);
n_pages = size >> PAGE_SHIFT;
*size = PAGE_ALIGN(*size);
n_pages = *size >> PAGE_SHIFT;
buf->page_array = kcalloc(n_pages, sizeof(struct page *), GFP_KERNEL);
if (!buf->page_array)
......@@ -118,7 +119,7 @@ static void *relay_alloc_buf(struct rchan_buf *buf, unsigned long size)
if (!mem)
goto depopulate;
memset(mem, 0, size);
memset(mem, 0, *size);
buf->page_count = n_pages;
return mem;
......@@ -146,7 +147,7 @@ struct rchan_buf *relay_create_buf(struct rchan *chan)
if (!buf->padding)
goto free_buf;
buf->start = relay_alloc_buf(buf, chan->alloc_size);
buf->start = relay_alloc_buf(buf, &chan->alloc_size);
if (!buf->start)
goto free_buf;
......@@ -543,6 +544,9 @@ size_t relay_switch_subbuf(struct rchan_buf *buf, size_t length)
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];
smp_mb();
if (waitqueue_active(&buf->read_wait)) {
PREPARE_WORK(&buf->wake_readers, wakeup_readers, buf);
schedule_delayed_work(&buf->wake_readers, 1);
......@@ -757,37 +761,33 @@ static void relay_file_read_consume(struct rchan_buf *buf,
*/
static int relay_file_read_avail(struct rchan_buf *buf, size_t read_pos)
{
size_t bytes_produced, bytes_consumed, write_offset;
size_t subbuf_size = buf->chan->subbuf_size;
size_t n_subbufs = buf->chan->n_subbufs;
size_t produced = buf->subbufs_produced % n_subbufs;
size_t consumed = buf->subbufs_consumed % n_subbufs;
size_t produced = buf->subbufs_produced;
size_t consumed = buf->subbufs_consumed;
write_offset = buf->offset > subbuf_size ? subbuf_size : buf->offset;
relay_file_read_consume(buf, read_pos, 0);
if (consumed > produced) {
if ((produced > n_subbufs) &&
(produced + n_subbufs - consumed <= n_subbufs))
produced += n_subbufs;
} else if (consumed == produced) {
if (buf->offset > subbuf_size) {
produced += n_subbufs;
if (buf->subbufs_produced == buf->subbufs_consumed)
consumed += n_subbufs;
}
if (unlikely(buf->offset > subbuf_size)) {
if (produced == consumed)
return 0;
return 1;
}
if (buf->offset > subbuf_size)
bytes_produced = (produced - 1) * subbuf_size + write_offset;
else
bytes_produced = produced * subbuf_size + write_offset;
bytes_consumed = consumed * subbuf_size + buf->bytes_consumed;
if (bytes_produced == bytes_consumed)
if (unlikely(produced - consumed >= n_subbufs)) {
consumed = (produced / n_subbufs) * n_subbufs;
buf->subbufs_consumed = consumed;
}
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)
return 0;
relay_file_read_consume(buf, read_pos, 0);
return 1;
}
......@@ -908,6 +908,91 @@ static ssize_t relay_file_read(struct file *filp,
return ret;
}
static ssize_t relay_file_sendsubbuf(struct file *filp, loff_t *ppos,
size_t count, read_actor_t actor,
void *target)
{
struct rchan_buf *buf = filp->private_data;
read_descriptor_t desc;
size_t read_start, avail;
unsigned long pidx, poff;
unsigned int subbuf_pages;
ssize_t ret = 0;
if (!relay_file_read_avail(buf, *ppos))
return 0;
read_start = relay_file_read_start_pos(*ppos, buf);
avail = relay_file_read_subbuf_avail(read_start, buf);
if (!avail)
return 0;
count = min(count, avail);
desc.written = 0;
desc.count = count;
desc.arg.data = target;
desc.error = 0;
subbuf_pages = buf->chan->alloc_size >> PAGE_SHIFT;
pidx = (read_start / PAGE_SIZE) % subbuf_pages;
poff = read_start & ~PAGE_MASK;
while (count) {
struct page *p = buf->page_array[pidx];
unsigned int len;
len = PAGE_SIZE - poff;
if (len > count)
len = count;
len = actor(&desc, p, poff, len);
if (desc.error) {
if (!ret)
ret = desc.error;
break;
}
count -= len;
ret += len;
poff = 0;
pidx = (pidx + 1) % subbuf_pages;
}
if (ret > 0) {
relay_file_read_consume(buf, read_start, ret);
*ppos = relay_file_read_end_pos(buf, read_start, ret);
}
return ret;
}
static ssize_t relay_file_sendfile(struct file *filp, loff_t *ppos,
size_t count, read_actor_t actor,
void *target)
{
ssize_t sent = 0, ret = 0;
if (!count)
return 0;
mutex_lock(&filp->f_dentry->d_inode->i_mutex);
do {
ret = relay_file_sendsubbuf(filp, ppos, count, actor, target);
if (ret < 0) {
if (!sent)
sent = ret;
break;
}
count -= ret;
sent += ret;
} while (count && ret);
mutex_unlock(&filp->f_dentry->d_inode->i_mutex);
return sent;
}
struct file_operations relay_file_operations = {
.open = relay_file_open,
.poll = relay_file_poll,
......@@ -915,5 +1000,6 @@ struct file_operations relay_file_operations = {
.read = relay_file_read,
.llseek = no_llseek,
.release = relay_file_release,
.sendfile = relay_file_sendfile,
};
EXPORT_SYMBOL_GPL(relay_file_operations);
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