[PATCH] relay: add sendfile() support
Signed-off-by: Jens Axboe <axboe@suse.de>
This commit is contained in:
Jens Axboe
parent
b86ff981a8
commit
221415d762
150
kernel/relay.c
150
kernel/relay.c
@ -95,15 +95,16 @@ int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma)
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* @buf: the buffer struct
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* @size: total size of the buffer
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*
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* Returns a pointer to the resulting buffer, NULL if unsuccessful
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* Returns a pointer to the resulting buffer, NULL if unsuccessful. The
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* passed in size will get page aligned, if it isn't already.
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*/
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static void *relay_alloc_buf(struct rchan_buf *buf, unsigned long size)
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static void *relay_alloc_buf(struct rchan_buf *buf, size_t *size)
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{
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void *mem;
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unsigned int i, j, n_pages;
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size = PAGE_ALIGN(size);
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n_pages = size >> PAGE_SHIFT;
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*size = PAGE_ALIGN(*size);
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n_pages = *size >> PAGE_SHIFT;
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buf->page_array = kcalloc(n_pages, sizeof(struct page *), GFP_KERNEL);
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if (!buf->page_array)
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@ -118,7 +119,7 @@ static void *relay_alloc_buf(struct rchan_buf *buf, unsigned long size)
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if (!mem)
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goto depopulate;
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memset(mem, 0, size);
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memset(mem, 0, *size);
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buf->page_count = n_pages;
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return mem;
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@ -146,7 +147,7 @@ struct rchan_buf *relay_create_buf(struct rchan *chan)
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if (!buf->padding)
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goto free_buf;
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buf->start = relay_alloc_buf(buf, chan->alloc_size);
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buf->start = relay_alloc_buf(buf, &chan->alloc_size);
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if (!buf->start)
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goto free_buf;
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@ -543,6 +544,9 @@ size_t relay_switch_subbuf(struct rchan_buf *buf, size_t length)
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old_subbuf = buf->subbufs_produced % buf->chan->n_subbufs;
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buf->padding[old_subbuf] = buf->prev_padding;
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buf->subbufs_produced++;
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buf->dentry->d_inode->i_size += buf->chan->subbuf_size -
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buf->padding[old_subbuf];
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smp_mb();
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if (waitqueue_active(&buf->read_wait)) {
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PREPARE_WORK(&buf->wake_readers, wakeup_readers, buf);
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schedule_delayed_work(&buf->wake_readers, 1);
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@ -757,37 +761,33 @@ static void relay_file_read_consume(struct rchan_buf *buf,
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*/
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static int relay_file_read_avail(struct rchan_buf *buf, size_t read_pos)
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{
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size_t bytes_produced, bytes_consumed, write_offset;
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size_t subbuf_size = buf->chan->subbuf_size;
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size_t n_subbufs = buf->chan->n_subbufs;
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size_t produced = buf->subbufs_produced % n_subbufs;
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size_t consumed = buf->subbufs_consumed % n_subbufs;
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write_offset = buf->offset > subbuf_size ? subbuf_size : buf->offset;
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if (consumed > produced) {
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if ((produced > n_subbufs) &&
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(produced + n_subbufs - consumed <= n_subbufs))
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produced += n_subbufs;
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} else if (consumed == produced) {
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if (buf->offset > subbuf_size) {
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produced += n_subbufs;
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if (buf->subbufs_produced == buf->subbufs_consumed)
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consumed += n_subbufs;
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}
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}
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if (buf->offset > subbuf_size)
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bytes_produced = (produced - 1) * subbuf_size + write_offset;
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else
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bytes_produced = produced * subbuf_size + write_offset;
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bytes_consumed = consumed * subbuf_size + buf->bytes_consumed;
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if (bytes_produced == bytes_consumed)
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return 0;
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size_t produced = buf->subbufs_produced;
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size_t consumed = buf->subbufs_consumed;
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relay_file_read_consume(buf, read_pos, 0);
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if (unlikely(buf->offset > subbuf_size)) {
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if (produced == consumed)
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return 0;
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return 1;
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}
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if (unlikely(produced - consumed >= n_subbufs)) {
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consumed = (produced / n_subbufs) * n_subbufs;
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buf->subbufs_consumed = consumed;
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}
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produced = (produced % n_subbufs) * subbuf_size + buf->offset;
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consumed = (consumed % n_subbufs) * subbuf_size + buf->bytes_consumed;
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if (consumed > produced)
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produced += n_subbufs * subbuf_size;
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if (consumed == produced)
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return 0;
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return 1;
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}
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@ -908,6 +908,91 @@ out:
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return ret;
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}
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static ssize_t relay_file_sendsubbuf(struct file *filp, loff_t *ppos,
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size_t count, read_actor_t actor,
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void *target)
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{
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struct rchan_buf *buf = filp->private_data;
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read_descriptor_t desc;
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size_t read_start, avail;
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unsigned long pidx, poff;
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unsigned int subbuf_pages;
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ssize_t ret = 0;
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if (!relay_file_read_avail(buf, *ppos))
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return 0;
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read_start = relay_file_read_start_pos(*ppos, buf);
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avail = relay_file_read_subbuf_avail(read_start, buf);
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if (!avail)
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return 0;
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count = min(count, avail);
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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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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 (count) {
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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 > count)
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len = count;
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len = actor(&desc, p, poff, len);
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if (desc.error) {
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if (!ret)
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ret = desc.error;
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break;
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}
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count -= 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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if (ret > 0) {
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relay_file_read_consume(buf, read_start, ret);
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*ppos = relay_file_read_end_pos(buf, read_start, ret);
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}
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return ret;
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}
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static ssize_t relay_file_sendfile(struct file *filp, loff_t *ppos,
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size_t count, read_actor_t actor,
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void *target)
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{
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ssize_t sent = 0, ret = 0;
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if (!count)
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return 0;
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mutex_lock(&filp->f_dentry->d_inode->i_mutex);
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do {
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ret = relay_file_sendsubbuf(filp, ppos, count, actor, target);
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if (ret < 0) {
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if (!sent)
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sent = ret;
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break;
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}
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count -= ret;
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sent += ret;
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} while (count && ret);
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mutex_unlock(&filp->f_dentry->d_inode->i_mutex);
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return sent;
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}
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struct file_operations relay_file_operations = {
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.open = relay_file_open,
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.poll = relay_file_poll,
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@ -915,5 +1000,6 @@ 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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};
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EXPORT_SYMBOL_GPL(relay_file_operations);
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