diff options
Diffstat (limited to 'kernel/relay.c')
| -rw-r--r-- | kernel/relay.c | 146 |
1 files changed, 55 insertions, 91 deletions
diff --git a/kernel/relay.c b/kernel/relay.c index 951f29b24e58..dd3bc5b69035 100644 --- a/kernel/relay.c +++ b/kernel/relay.c @@ -1032,19 +1032,23 @@ static ssize_t relay_file_read(struct file *filp, NULL, &desc); } +static void relay_consume_bytes(struct rchan_buf *rbuf, int bytes_consumed) +{ + rbuf->bytes_consumed += bytes_consumed; + + if (rbuf->bytes_consumed >= rbuf->chan->subbuf_size) { + relay_subbufs_consumed(rbuf->chan, rbuf->cpu, 1); + rbuf->bytes_consumed %= rbuf->chan->subbuf_size; + } +} + static void relay_pipe_buf_release(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { 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; - } + relay_consume_bytes(rbuf, buf->private); } static struct pipe_buf_operations relay_pipe_buf_ops = { @@ -1067,118 +1071,79 @@ static int subbuf_splice_actor(struct file *in, unsigned int flags, int *nonpad_ret) { - unsigned int pidx, poff; - unsigned int subbuf_pages; - int ret = 0; - int do_wakeup = 0; + unsigned int pidx, poff, total_len, subbuf_pages, ret; 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; + struct page *pages[PIPE_BUFFERS]; + struct partial_page partial[PIPE_BUFFERS]; + struct splice_pipe_desc spd = { + .pages = pages, + .nr_pages = 0, + .partial = partial, + .flags = flags, + .ops = &relay_pipe_buf_ops, + }; if (rbuf->subbufs_produced == rbuf->subbufs_consumed) return 0; - if (len > avail) - len = avail; - - if (pipe->inode) - mutex_lock(&pipe->inode->i_mutex); + /* + * Adjust read len, if longer than what is available + */ + if (len > (subbuf_size - read_start % subbuf_size)) + len = subbuf_size - read_start % subbuf_size; 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; + for (total_len = 0; spd.nr_pages < subbuf_pages; spd.nr_pages++) { + unsigned int this_len, this_end, private; + unsigned int cur_pos = read_start + total_len; - if (!pipe->readers) { - send_sig(SIGPIPE, current, 0); - if (!ret) - ret = -EPIPE; + if (!len) 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; + this_len = min_t(unsigned long, len, PAGE_SIZE - poff); + private = this_len; - if (pipe->inode) - do_wakeup = 1; + spd.pages[spd.nr_pages] = rbuf->page_array[pidx]; + spd.partial[spd.nr_pages].offset = poff; - if (!avail) - break; - - if (pipe->nrbufs < PIPE_BUFFERS) - continue; - - break; + this_end = cur_pos + this_len; + if (this_end >= nonpad_end) { + this_len = nonpad_end - cur_pos; + private = this_len + padding; } + spd.partial[spd.nr_pages].len = this_len; + spd.partial[spd.nr_pages].private = private; - if (flags & SPLICE_F_NONBLOCK) { - if (!ret) - ret = -EAGAIN; - break; - } + len -= this_len; + total_len += this_len; + poff = 0; + pidx = (pidx + 1) % subbuf_pages; - if (signal_pending(current)) { - if (!ret) - ret = -ERESTARTSYS; + if (this_end >= nonpad_end) { + spd.nr_pages++; 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 (!spd.nr_pages) + return 0; - if (do_wakeup) { - smp_mb(); - if (waitqueue_active(&pipe->wait)) - wake_up_interruptible(&pipe->wait); - kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); - } + ret = *nonpad_ret = splice_to_pipe(pipe, &spd); + if (ret < 0 || ret < total_len) + return ret; - return ret; + if (read_start + ret == nonpad_end) + ret += padding; + + return ret; } static ssize_t relay_file_splice_read(struct file *in, @@ -1199,7 +1164,6 @@ static ssize_t relay_file_splice_read(struct file *in, if (ret < 0) break; else if (!ret) { - break; if (spliced) break; if (flags & SPLICE_F_NONBLOCK) { |