static ssize_t
pipe_writev(struct file *filp, const struct iovec *_iov,
unsigned long nr_segs, loff_t *ppos)
{
struct inode *inode = filp->f_dentry->d_inode;
ssize_t ret;
size_t min;
int do_wakeup;
struct iovec *iov = (struct iovec *)_iov;
size_t total_len;
total_len = iov_length(iov, nr_segs);
/* Null write succeeds. */
if (unlikely(total_len == 0))
return 0;
do_wakeup = 0;
ret = 0;
min = total_len;
if (min > PIPE_BUF)
min = 1;
down(PIPE_SEM(*inode));
for (;;) {
int free;
if (!PIPE_READERS(*inode)) {
send_sig(SIGPIPE, current, 0);
if (!ret) ret = -EPIPE;
break;
}
free = PIPE_FREE(*inode);
if (free >= min) {
/* transfer data */
ssize_t chars = PIPE_MAX_WCHUNK(*inode);
char *pipebuf = PIPE_BASE(*inode) + PIPE_END(*inode);
/* Always wakeup, even if the copy fails. Otherwise
* we lock up (O_NONBLOCK-)readers that sleep due to
* syscall merging.
*/
do_wakeup = 1;
if (chars > total_len)
chars = total_len;
if (chars > free)
chars = free;
if (pipe_iov_copy_from_user(pipebuf, iov, chars)) {
if (!ret) ret = -EFAULT;
break;
}
ret += chars;
PIPE_LEN(*inode) += chars;
total_len -= chars;
if (!total_len)
break;
}
if (PIPE_FREE(*inode) && ret) {
/* handle cyclic data buffers */
min = 1;
continue;
}
if (filp->f_flags & O_NONBLOCK) {
if (!ret) ret = -EAGAIN;
break;
}
if (signal_pending(current)) {
if (!ret) ret = -ERESTARTSYS;
break;
}
if (do_wakeup) {
wake_up_interruptible_sync(PIPE_WAIT(*inode));
kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN);
do_wakeup = 0;
}
PIPE_WAITING_WRITERS(*inode)++;
pipe_wait(inode);
PIPE_WAITING_WRITERS(*inode)--;
}
up(PIPE_SEM(*inode));
if (do_wakeup) {
wake_up_interruptible(PIPE_WAIT(*inode));
kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN);
}
/*
* Hack: we turn off atime updates for -RT kernels.
* Who uses them on pipes anyway?
*/
#ifndef CONFIG_PREEMPT_RT
if (ret > 0)
inode_update_time(inode, 1); /* mtime and ctime */
#endif
return ret;
}
static ssize_t
pipe_write(struct kiocb *iocb, const struct iovec *_iov,
unsigned long nr_segs, loff_t ppos)
{
struct file *filp = iocb->ki_filp;
struct inode *inode = filp->f_path.dentry->d_inode;
struct pipe_inode_info *pipe;
ssize_t ret;
int do_wakeup;
struct iovec *iov = (struct iovec *)_iov;
size_t total_len;
ssize_t chars;
total_len = iov_length(iov, nr_segs);
/* Null write succeeds. */
if (unlikely(total_len == 0))
return 0;
do_wakeup = 0;
ret = 0;
mutex_lock(&inode->i_mutex);
pipe = inode->i_pipe;
if (!pipe->readers) {
send_sig(SIGPIPE, current, 0);
ret = -EPIPE;
goto out;
}
/* We try to merge small writes */
chars = total_len & (PAGE_SIZE-1); /* size of the last buffer */
if (pipe->nrbufs && chars != 0) {
int lastbuf = (pipe->curbuf + pipe->nrbufs - 1) &
(pipe->buffers - 1);
struct pipe_buffer *buf = pipe->bufs + lastbuf;
const struct pipe_buf_operations *ops = buf->ops;
int offset = buf->offset + buf->len;
if (ops->can_merge && offset + chars <= PAGE_SIZE) {
int error, atomic = 1;
void *addr;
error = ops->confirm(pipe, buf);
if (error)
goto out;
iov_fault_in_pages_read(iov, chars);
redo1:
addr = ops->map(pipe, buf, atomic);
error = pipe_iov_copy_from_user(offset + addr, iov,
chars, atomic);
ops->unmap(pipe, buf, addr);
ret = error;
do_wakeup = 1;
if (error) {
if (atomic) {
atomic = 0;
goto redo1;
}
goto out;
}
buf->len += chars;
total_len -= chars;
ret = chars;
if (!total_len)
goto out;
}
}
for (;;) {
int bufs;
if (!pipe->readers) {
send_sig(SIGPIPE, current, 0);
if (!ret)
ret = -EPIPE;
break;
}
bufs = pipe->nrbufs;
if (bufs < pipe->buffers) {
int newbuf = (pipe->curbuf + bufs) & (pipe->buffers-1);
struct pipe_buffer *buf = pipe->bufs + newbuf;
struct page *page = pipe->tmp_page;
char *src;
int error, atomic = 1;
if (!page) {
page = alloc_page(GFP_HIGHUSER);
if (unlikely(!page)) {
ret = ret ? : -ENOMEM;
break;
}
pipe->tmp_page = page;
}
static ssize_t
pipe_writev(struct file *filp, const struct iovec *_iov,
unsigned long nr_segs, loff_t *ppos)
{
struct inode *inode = filp->f_dentry->d_inode;
struct pipe_inode_info *info;
ssize_t ret;
int do_wakeup;
struct iovec *iov = (struct iovec *)_iov;
size_t total_len;
ssize_t chars;
total_len = iov_length(iov, nr_segs);
/* Null write succeeds. */
if (unlikely(total_len == 0))
return 0;
do_wakeup = 0;
ret = 0;
down(PIPE_SEM(*inode));
info = inode->i_pipe;
if (!PIPE_READERS(*inode)) {
send_sig(SIGPIPE, current, 0);
ret = -EPIPE;
goto out;
}
/* We try to merge small writes */
chars = total_len & (PAGE_SIZE-1); /* size of the last buffer */
if (info->nrbufs && chars != 0) {
int lastbuf = (info->curbuf + info->nrbufs - 1) & (PIPE_BUFFERS-1);
struct pipe_buffer *buf = info->bufs + lastbuf;
struct pipe_buf_operations *ops = buf->ops;
int offset = buf->offset + buf->len;
if (ops->can_merge && offset + chars <= PAGE_SIZE) {
void *addr = ops->map(filp, info, buf);
int error = pipe_iov_copy_from_user(offset + addr, iov, chars);
ops->unmap(info, buf);
ret = error;
do_wakeup = 1;
if (error)
goto out;
buf->len += chars;
total_len -= chars;
ret = chars;
if (!total_len)
goto out;
}
}
for (;;) {
int bufs;
if (!PIPE_READERS(*inode)) {
send_sig(SIGPIPE, current, 0);
if (!ret) ret = -EPIPE;
break;
}
bufs = info->nrbufs;
if (bufs < PIPE_BUFFERS) {
int newbuf = (info->curbuf + bufs) & (PIPE_BUFFERS-1);
struct pipe_buffer *buf = info->bufs + newbuf;
struct page *page = info->tmp_page;
int error;
if (!page) {
page = alloc_page(GFP_HIGHUSER);
if (unlikely(!page)) {
ret = ret ? : -ENOMEM;
break;
}
info->tmp_page = page;
}
