Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
fs/splice.c | 135 ++++++++++++++++--------------------------------------------
1 file changed, 36 insertions(+), 99 deletions(-)
diff --git a/fs/splice.c b/fs/splice.c
index 36e9353..31c52e0 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;
}
--
2.9.3
|