diff options
| -rw-r--r-- | fs/splice.c | 135 |
1 files changed, 36 insertions, 99 deletions
diff --git a/fs/splice.c b/fs/splice.c index 36e9353c1910..31c52e0269c2 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -1434,106 +1434,32 @@ static long do_splice(struct file *in, loff_t __user *off_in, return -EINVAL; } -/* - * Map an iov into an array of pages and offset/length tupples. With the - * partial_page structure, we can map several non-contiguous ranges into - * our ones pages[] map instead of splitting that operation into pieces. - * Could easily be exported as a generic helper for other users, in which - * case one would probably want to add a 'max_nr_pages' parameter as well. - */ -static int get_iovec_page_array(const struct iovec __user *iov, - unsigned int nr_vecs, struct page **pages, - struct partial_page *partial, bool aligned, +static int get_iovec_page_array(struct iov_iter *from, + struct page **pages, + struct partial_page *partial, unsigned int pipe_buffers) { - int buffers = 0, error = 0; - - while (nr_vecs) { - unsigned long off, npages; - struct iovec entry; - void __user *base; - size_t len; - int i; - - error = -EFAULT; - if (copy_from_user(&entry, iov, sizeof(entry))) - break; - - base = entry.iov_base; - len = entry.iov_len; - - /* - * Sanity check this iovec. 0 read succeeds. - */ - error = 0; - if (unlikely(!len)) - break; - error = -EFAULT; - if (!access_ok(VERIFY_READ, base, len)) - break; - - /* - * Get this base offset and number of pages, then map - * in the user pages. - */ - off = (unsigned long) base & ~PAGE_MASK; - - /* - * If asked for alignment, the offset must be zero and the - * length a multiple of the PAGE_SIZE. - */ - error = -EINVAL; - if (aligned && (off || len & ~PAGE_MASK)) - break; - - npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; - if (npages > pipe_buffers - buffers) - npages = pipe_buffers - buffers; - - error = get_user_pages_fast((unsigned long)base, npages, - 0, &pages[buffers]); - - if (unlikely(error <= 0)) - break; - - /* - * Fill this contiguous range into the partial page map. - */ - for (i = 0; i < error; i++) { - const int plen = min_t(size_t, len, PAGE_SIZE - off); - - partial[buffers].offset = off; - partial[buffers].len = plen; - - off = 0; - len -= plen; + int buffers = 0; + while (iov_iter_count(from)) { + ssize_t copied; + size_t start; + + copied = iov_iter_get_pages(from, pages + buffers, ~0UL, + pipe_buffers - buffers, &start); + if (copied <= 0) + return buffers ? buffers : copied; + + iov_iter_advance(from, copied); + while (copied) { + int size = min_t(int, copied, PAGE_SIZE - start); + partial[buffers].offset = start; + partial[buffers].len = size; + copied -= size; + start = 0; buffers++; } - - /* - * We didn't complete this iov, stop here since it probably - * means we have to move some of this into a pipe to - * be able to continue. - */ - if (len) - break; - - /* - * Don't continue if we mapped fewer pages than we asked for, - * or if we mapped the max number of pages that we have - * room for. - */ - if (error < npages || buffers == pipe_buffers) - break; - - nr_vecs--; - iov++; } - - if (buffers) - return buffers; - - return error; + return buffers; } static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf, @@ -1587,10 +1513,13 @@ static long vmsplice_to_user(struct file *file, const struct iovec __user *uiov, * as splice-from-memory, where the regular splice is splice-from-file (or * to file). In both cases the output is a pipe, naturally. */ -static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov, +static long vmsplice_to_pipe(struct file *file, const struct iovec __user *uiov, unsigned long nr_segs, unsigned int flags) { struct pipe_inode_info *pipe; + struct iovec iovstack[UIO_FASTIOV]; + struct iovec *iov = iovstack; + struct iov_iter from; struct page *pages[PIPE_DEF_BUFFERS]; struct partial_page partial[PIPE_DEF_BUFFERS]; struct splice_pipe_desc spd = { @@ -1607,11 +1536,18 @@ static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov, if (!pipe) return -EBADF; - if (splice_grow_spd(pipe, &spd)) + ret = import_iovec(WRITE, uiov, nr_segs, + ARRAY_SIZE(iovstack), &iov, &from); + if (ret < 0) + return ret; + + if (splice_grow_spd(pipe, &spd)) { + kfree(iov); return -ENOMEM; + } - spd.nr_pages = get_iovec_page_array(iov, nr_segs, spd.pages, - spd.partial, false, + spd.nr_pages = get_iovec_page_array(&from, spd.pages, + spd.partial, spd.nr_pages_max); if (spd.nr_pages <= 0) ret = spd.nr_pages; @@ -1619,6 +1555,7 @@ static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov, ret = splice_to_pipe(pipe, &spd); splice_shrink_spd(&spd); + kfree(iov); return ret; } |