splice: switch get_iovec_page_array() to iov_iter
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
Родитель
e7c3c64624
Коммит
db85a9eb2e
133
fs/splice.c
133
fs/splice.c
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@ -1434,106 +1434,32 @@ static long do_splice(struct file *in, loff_t __user *off_in,
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return -EINVAL;
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}
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/*
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* Map an iov into an array of pages and offset/length tupples. With the
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* partial_page structure, we can map several non-contiguous ranges into
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* our ones pages[] map instead of splitting that operation into pieces.
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* Could easily be exported as a generic helper for other users, in which
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* case one would probably want to add a 'max_nr_pages' parameter as well.
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*/
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static int get_iovec_page_array(const struct iovec __user *iov,
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unsigned int nr_vecs, struct page **pages,
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struct partial_page *partial, bool aligned,
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static int get_iovec_page_array(struct iov_iter *from,
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struct page **pages,
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struct partial_page *partial,
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unsigned int pipe_buffers)
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{
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int buffers = 0, error = 0;
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int buffers = 0;
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while (iov_iter_count(from)) {
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ssize_t copied;
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size_t start;
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while (nr_vecs) {
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unsigned long off, npages;
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struct iovec entry;
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void __user *base;
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size_t len;
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int i;
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copied = iov_iter_get_pages(from, pages + buffers, ~0UL,
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pipe_buffers - buffers, &start);
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if (copied <= 0)
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return buffers ? buffers : copied;
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error = -EFAULT;
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if (copy_from_user(&entry, iov, sizeof(entry)))
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break;
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base = entry.iov_base;
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len = entry.iov_len;
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/*
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* Sanity check this iovec. 0 read succeeds.
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*/
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error = 0;
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if (unlikely(!len))
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break;
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error = -EFAULT;
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if (!access_ok(VERIFY_READ, base, len))
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break;
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/*
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* Get this base offset and number of pages, then map
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* in the user pages.
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*/
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off = (unsigned long) base & ~PAGE_MASK;
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/*
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* If asked for alignment, the offset must be zero and the
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* length a multiple of the PAGE_SIZE.
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*/
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error = -EINVAL;
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if (aligned && (off || len & ~PAGE_MASK))
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break;
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npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
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if (npages > pipe_buffers - buffers)
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npages = pipe_buffers - buffers;
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error = get_user_pages_fast((unsigned long)base, npages,
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0, &pages[buffers]);
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if (unlikely(error <= 0))
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break;
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/*
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* Fill this contiguous range into the partial page map.
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*/
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for (i = 0; i < error; i++) {
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const int plen = min_t(size_t, len, PAGE_SIZE - off);
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partial[buffers].offset = off;
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partial[buffers].len = plen;
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off = 0;
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len -= plen;
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iov_iter_advance(from, copied);
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while (copied) {
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int size = min_t(int, copied, PAGE_SIZE - start);
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partial[buffers].offset = start;
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partial[buffers].len = size;
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copied -= size;
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start = 0;
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buffers++;
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}
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/*
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* We didn't complete this iov, stop here since it probably
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* means we have to move some of this into a pipe to
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* be able to continue.
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*/
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if (len)
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break;
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/*
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* Don't continue if we mapped fewer pages than we asked for,
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* or if we mapped the max number of pages that we have
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* room for.
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*/
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if (error < npages || buffers == pipe_buffers)
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break;
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nr_vecs--;
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iov++;
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}
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if (buffers)
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return buffers;
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return error;
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return buffers;
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}
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static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
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@ -1587,10 +1513,13 @@ static long vmsplice_to_user(struct file *file, const struct iovec __user *uiov,
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* as splice-from-memory, where the regular splice is splice-from-file (or
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* to file). In both cases the output is a pipe, naturally.
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*/
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static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov,
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static long vmsplice_to_pipe(struct file *file, const struct iovec __user *uiov,
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unsigned long nr_segs, unsigned int flags)
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{
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struct pipe_inode_info *pipe;
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struct iovec iovstack[UIO_FASTIOV];
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struct iovec *iov = iovstack;
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struct iov_iter from;
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struct page *pages[PIPE_DEF_BUFFERS];
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struct partial_page partial[PIPE_DEF_BUFFERS];
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struct splice_pipe_desc spd = {
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@ -1607,11 +1536,18 @@ static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov,
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if (!pipe)
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return -EBADF;
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if (splice_grow_spd(pipe, &spd))
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return -ENOMEM;
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ret = import_iovec(WRITE, uiov, nr_segs,
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ARRAY_SIZE(iovstack), &iov, &from);
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if (ret < 0)
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return ret;
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spd.nr_pages = get_iovec_page_array(iov, nr_segs, spd.pages,
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spd.partial, false,
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if (splice_grow_spd(pipe, &spd)) {
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kfree(iov);
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return -ENOMEM;
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}
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spd.nr_pages = get_iovec_page_array(&from, spd.pages,
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spd.partial,
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spd.nr_pages_max);
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if (spd.nr_pages <= 0)
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ret = spd.nr_pages;
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@ -1619,6 +1555,7 @@ static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov,
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ret = splice_to_pipe(pipe, &spd);
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splice_shrink_spd(&spd);
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kfree(iov);
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return ret;
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}
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