forked from Minki/linux
new helper: copy_page_from_iter()
parallel to copy_page_to_iter(). pipe_write() switched to it (and became ->write_iter()). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
parent
84c3d55cc4
commit
f0d1bec9d5
129
fs/pipe.c
129
fs/pipe.c
@ -116,50 +116,6 @@ void pipe_wait(struct pipe_inode_info *pipe)
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pipe_lock(pipe);
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}
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static int
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pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len,
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int atomic)
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{
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unsigned long copy;
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while (len > 0) {
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while (!iov->iov_len)
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iov++;
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copy = min_t(unsigned long, len, iov->iov_len);
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if (atomic) {
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if (__copy_from_user_inatomic(to, iov->iov_base, copy))
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return -EFAULT;
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} else {
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if (copy_from_user(to, iov->iov_base, copy))
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return -EFAULT;
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}
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to += copy;
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len -= copy;
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iov->iov_base += copy;
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iov->iov_len -= copy;
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}
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return 0;
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}
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/*
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* Pre-fault in the user memory, so we can use atomic copies.
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*/
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static void iov_fault_in_pages_read(struct iovec *iov, unsigned long len)
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{
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while (!iov->iov_len)
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iov++;
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while (len > 0) {
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unsigned long this_len;
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this_len = min_t(unsigned long, len, iov->iov_len);
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fault_in_pages_readable(iov->iov_base, this_len);
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len -= this_len;
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iov++;
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}
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}
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static void anon_pipe_buf_release(struct pipe_inode_info *pipe,
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struct pipe_buffer *buf)
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{
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@ -380,24 +336,19 @@ static inline int is_packetized(struct file *file)
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}
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static ssize_t
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pipe_write(struct kiocb *iocb, const struct iovec *_iov,
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unsigned long nr_segs, loff_t ppos)
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pipe_write(struct kiocb *iocb, struct iov_iter *from)
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{
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struct file *filp = iocb->ki_filp;
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struct pipe_inode_info *pipe = filp->private_data;
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ssize_t ret;
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int do_wakeup;
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struct iovec *iov = (struct iovec *)_iov;
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size_t total_len;
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ssize_t ret = 0;
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int do_wakeup = 0;
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size_t total_len = iov_iter_count(from);
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ssize_t chars;
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total_len = iov_length(iov, nr_segs);
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/* Null write succeeds. */
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if (unlikely(total_len == 0))
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return 0;
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do_wakeup = 0;
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ret = 0;
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__pipe_lock(pipe);
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if (!pipe->readers) {
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@ -416,38 +367,19 @@ pipe_write(struct kiocb *iocb, const struct iovec *_iov,
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int offset = buf->offset + buf->len;
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if (ops->can_merge && offset + chars <= PAGE_SIZE) {
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int error, atomic = 1;
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void *addr;
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error = ops->confirm(pipe, buf);
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int error = ops->confirm(pipe, buf);
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if (error)
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goto out;
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iov_fault_in_pages_read(iov, chars);
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redo1:
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if (atomic)
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addr = kmap_atomic(buf->page);
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else
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addr = kmap(buf->page);
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error = pipe_iov_copy_from_user(offset + addr, iov,
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chars, atomic);
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if (atomic)
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kunmap_atomic(addr);
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else
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kunmap(buf->page);
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ret = error;
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do_wakeup = 1;
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if (error) {
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if (atomic) {
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atomic = 0;
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goto redo1;
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}
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ret = copy_page_from_iter(buf->page, offset, chars, from);
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if (unlikely(ret < chars)) {
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error = -EFAULT;
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goto out;
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}
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do_wakeup = 1;
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buf->len += chars;
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total_len -= chars;
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ret = chars;
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if (!total_len)
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if (!iov_iter_count(from))
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goto out;
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}
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}
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@ -466,8 +398,7 @@ redo1:
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int newbuf = (pipe->curbuf + bufs) & (pipe->buffers-1);
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struct pipe_buffer *buf = pipe->bufs + newbuf;
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struct page *page = pipe->tmp_page;
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char *src;
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int error, atomic = 1;
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int copied;
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if (!page) {
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page = alloc_page(GFP_HIGHUSER);
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@ -483,40 +414,19 @@ redo1:
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* FIXME! Is this really true?
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*/
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do_wakeup = 1;
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chars = PAGE_SIZE;
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if (chars > total_len)
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chars = total_len;
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iov_fault_in_pages_read(iov, chars);
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redo2:
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if (atomic)
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src = kmap_atomic(page);
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else
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src = kmap(page);
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error = pipe_iov_copy_from_user(src, iov, chars,
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atomic);
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if (atomic)
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kunmap_atomic(src);
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else
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kunmap(page);
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if (unlikely(error)) {
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if (atomic) {
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atomic = 0;
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goto redo2;
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}
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copied = copy_page_from_iter(page, 0, PAGE_SIZE, from);
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if (unlikely(copied < PAGE_SIZE && iov_iter_count(from))) {
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if (!ret)
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ret = error;
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ret = -EFAULT;
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break;
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}
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ret += chars;
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ret += copied;
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/* Insert it into the buffer array */
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buf->page = page;
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buf->ops = &anon_pipe_buf_ops;
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buf->offset = 0;
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buf->len = chars;
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buf->len = copied;
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buf->flags = 0;
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if (is_packetized(filp)) {
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buf->ops = &packet_pipe_buf_ops;
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@ -525,8 +435,7 @@ redo2:
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pipe->nrbufs = ++bufs;
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pipe->tmp_page = NULL;
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total_len -= chars;
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if (!total_len)
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if (!iov_iter_count(from))
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break;
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}
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if (bufs < pipe->buffers)
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@ -1040,8 +949,8 @@ const struct file_operations pipefifo_fops = {
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.llseek = no_llseek,
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.read = new_sync_read,
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.read_iter = pipe_read,
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.write = do_sync_write,
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.aio_write = pipe_write,
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.write = new_sync_write,
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.write_iter = pipe_write,
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.poll = pipe_poll,
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.unlocked_ioctl = pipe_ioctl,
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.release = pipe_release,
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@ -68,6 +68,8 @@ int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
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size_t iov_iter_single_seg_count(const struct iov_iter *i);
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size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
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struct iov_iter *i);
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size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
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struct iov_iter *i);
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unsigned long iov_iter_alignment(const struct iov_iter *i);
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void iov_iter_init(struct iov_iter *i, int direction, const struct iovec *iov,
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unsigned long nr_segs, size_t count);
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@ -82,6 +82,84 @@ done:
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}
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EXPORT_SYMBOL(copy_page_to_iter);
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size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
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struct iov_iter *i)
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{
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size_t skip, copy, left, wanted;
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const struct iovec *iov;
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char __user *buf;
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void *kaddr, *to;
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if (unlikely(bytes > i->count))
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bytes = i->count;
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if (unlikely(!bytes))
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return 0;
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wanted = bytes;
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iov = i->iov;
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skip = i->iov_offset;
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buf = iov->iov_base + skip;
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copy = min(bytes, iov->iov_len - skip);
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if (!fault_in_pages_readable(buf, copy)) {
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kaddr = kmap_atomic(page);
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to = kaddr + offset;
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/* first chunk, usually the only one */
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left = __copy_from_user_inatomic(to, buf, copy);
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copy -= left;
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skip += copy;
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to += copy;
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bytes -= copy;
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while (unlikely(!left && bytes)) {
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iov++;
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buf = iov->iov_base;
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copy = min(bytes, iov->iov_len);
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left = __copy_from_user_inatomic(to, buf, copy);
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copy -= left;
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skip = copy;
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to += copy;
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bytes -= copy;
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}
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if (likely(!bytes)) {
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kunmap_atomic(kaddr);
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goto done;
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}
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offset = to - kaddr;
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buf += copy;
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kunmap_atomic(kaddr);
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copy = min(bytes, iov->iov_len - skip);
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}
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/* Too bad - revert to non-atomic kmap */
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kaddr = kmap(page);
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to = kaddr + offset;
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left = __copy_from_user(to, buf, copy);
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copy -= left;
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skip += copy;
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to += copy;
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bytes -= copy;
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while (unlikely(!left && bytes)) {
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iov++;
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buf = iov->iov_base;
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copy = min(bytes, iov->iov_len);
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left = __copy_from_user(to, buf, copy);
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copy -= left;
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skip = copy;
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to += copy;
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bytes -= copy;
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}
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kunmap(page);
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done:
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i->count -= wanted - bytes;
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i->nr_segs -= iov - i->iov;
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i->iov = iov;
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i->iov_offset = skip;
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return wanted - bytes;
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}
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EXPORT_SYMBOL(copy_page_from_iter);
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static size_t __iovec_copy_from_user_inatomic(char *vaddr,
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const struct iovec *iov, size_t base, size_t bytes)
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{
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