X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=fs%2Fsplice.c;h=684bca3d3a107c021715f8394a1f1d23a1913aaa;hb=7845701820c420454bcfdc4902fad68901d9ff83;hp=a46ddd28561ea2ed74ae133d20c8220425f3651f;hpb=eb20796bf6fdb95ccf51440ba2a827149bdc037f;p=powerpc.git

diff --git a/fs/splice.c b/fs/splice.c
index a46ddd2856..684bca3d3a 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -51,48 +51,58 @@ struct splice_pipe_desc {
  * addition of remove_mapping(). If success is returned, the caller may
  * attempt to reuse this page for another destination.
  */
-static int page_cache_pipe_buf_steal(struct pipe_inode_info *info,
+static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe,
 				     struct pipe_buffer *buf)
 {
 	struct page *page = buf->page;
-	struct address_space *mapping = page_mapping(page);
+	struct address_space *mapping;
 
 	lock_page(page);
 
-	WARN_ON(!PageUptodate(page));
+	mapping = page_mapping(page);
+	if (mapping) {
+		WARN_ON(!PageUptodate(page));
 
-	/*
-	 * At least for ext2 with nobh option, we need to wait on writeback
-	 * completing on this page, since we'll remove it from the pagecache.
-	 * Otherwise truncate wont wait on the page, allowing the disk
-	 * blocks to be reused by someone else before we actually wrote our
-	 * data to them. fs corruption ensues.
-	 */
-	wait_on_page_writeback(page);
+		/*
+		 * At least for ext2 with nobh option, we need to wait on
+		 * writeback completing on this page, since we'll remove it
+		 * from the pagecache.  Otherwise truncate wont wait on the
+		 * page, allowing the disk blocks to be reused by someone else
+		 * before we actually wrote our data to them. fs corruption
+		 * ensues.
+		 */
+		wait_on_page_writeback(page);
 
-	if (PagePrivate(page))
-		try_to_release_page(page, mapping_gfp_mask(mapping));
+		if (PagePrivate(page))
+			try_to_release_page(page, mapping_gfp_mask(mapping));
 
-	if (!remove_mapping(mapping, page)) {
-		unlock_page(page);
-		return 1;
+		/*
+		 * If we succeeded in removing the mapping, set LRU flag
+		 * and return good.
+		 */
+		if (remove_mapping(mapping, page)) {
+			buf->flags |= PIPE_BUF_FLAG_LRU;
+			return 0;
+		}
 	}
 
-	buf->flags |= PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU;
-	return 0;
+	/*
+	 * Raced with truncate or failed to remove page from current
+	 * address space, unlock and return failure.
+	 */
+	unlock_page(page);
+	return 1;
 }
 
-static void page_cache_pipe_buf_release(struct pipe_inode_info *info,
+static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe,
 					struct pipe_buffer *buf)
 {
 	page_cache_release(buf->page);
-	buf->page = NULL;
-	buf->flags &= ~(PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU);
+	buf->flags &= ~PIPE_BUF_FLAG_LRU;
 }
 
-static void *page_cache_pipe_buf_map(struct file *file,
-				     struct pipe_inode_info *info,
-				     struct pipe_buffer *buf)
+static int page_cache_pipe_buf_pin(struct pipe_inode_info *pipe,
+				   struct pipe_buffer *buf)
 {
 	struct page *page = buf->page;
 	int err;
@@ -118,64 +128,45 @@ static void *page_cache_pipe_buf_map(struct file *file,
 		}
 
 		/*
-		 * Page is ok afterall, fall through to mapping.
+		 * Page is ok afterall, we are done.
 		 */
 		unlock_page(page);
 	}
 
-	return kmap(page);
+	return 0;
 error:
 	unlock_page(page);
-	return ERR_PTR(err);
-}
-
-static void page_cache_pipe_buf_unmap(struct pipe_inode_info *info,
-				      struct pipe_buffer *buf)
-{
-	kunmap(buf->page);
-}
-
-static void *user_page_pipe_buf_map(struct file *file,
-				    struct pipe_inode_info *pipe,
-				    struct pipe_buffer *buf)
-{
-	return kmap(buf->page);
-}
-
-static void user_page_pipe_buf_unmap(struct pipe_inode_info *pipe,
-				     struct pipe_buffer *buf)
-{
-	kunmap(buf->page);
-}
-
-static void page_cache_pipe_buf_get(struct pipe_inode_info *info,
-				    struct pipe_buffer *buf)
-{
-	page_cache_get(buf->page);
+	return err;
 }
 
 static struct pipe_buf_operations page_cache_pipe_buf_ops = {
 	.can_merge = 0,
-	.map = page_cache_pipe_buf_map,
-	.unmap = page_cache_pipe_buf_unmap,
+	.map = generic_pipe_buf_map,
+	.unmap = generic_pipe_buf_unmap,
+	.pin = page_cache_pipe_buf_pin,
 	.release = page_cache_pipe_buf_release,
 	.steal = page_cache_pipe_buf_steal,
-	.get = page_cache_pipe_buf_get,
+	.get = generic_pipe_buf_get,
 };
 
 static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe,
 				    struct pipe_buffer *buf)
 {
-	return 1;
+	if (!(buf->flags & PIPE_BUF_FLAG_GIFT))
+		return 1;
+
+	buf->flags |= PIPE_BUF_FLAG_LRU;
+	return generic_pipe_buf_steal(pipe, buf);
 }
 
 static struct pipe_buf_operations user_page_pipe_buf_ops = {
 	.can_merge = 0,
-	.map = user_page_pipe_buf_map,
-	.unmap = user_page_pipe_buf_unmap,
+	.map = generic_pipe_buf_map,
+	.unmap = generic_pipe_buf_unmap,
+	.pin = generic_pipe_buf_pin,
 	.release = page_cache_pipe_buf_release,
 	.steal = user_page_pipe_buf_steal,
-	.get = page_cache_pipe_buf_get,
+	.get = generic_pipe_buf_get,
 };
 
 /*
@@ -210,6 +201,9 @@ static ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
 			buf->offset = spd->partial[page_nr].offset;
 			buf->len = spd->partial[page_nr].len;
 			buf->ops = spd->ops;
+			if (spd->flags & SPLICE_F_GIFT)
+				buf->flags |= PIPE_BUF_FLAG_GIFT;
+
 			pipe->nrbufs++;
 			page_nr++;
 			ret += buf->len;
@@ -325,6 +319,12 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
 		 */
 		page = find_get_page(mapping, index);
 		if (!page) {
+			/*
+			 * Make sure the read-ahead engine is notified
+			 * about this failure.
+			 */
+			handle_ra_miss(mapping, &in->f_ra, index);
+
 			/*
 			 * page didn't exist, allocate one.
 			 */
@@ -336,6 +336,8 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
 					      mapping_gfp_mask(mapping));
 			if (unlikely(error)) {
 				page_cache_release(page);
+				if (error == -EEXIST)
+					continue;
 				break;
 			}
 			/*
@@ -512,31 +514,21 @@ EXPORT_SYMBOL(generic_file_splice_read);
  * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos'
  * using sendpage(). Return the number of bytes sent.
  */
-static int pipe_to_sendpage(struct pipe_inode_info *info,
+static int pipe_to_sendpage(struct pipe_inode_info *pipe,
 			    struct pipe_buffer *buf, struct splice_desc *sd)
 {
 	struct file *file = sd->file;
 	loff_t pos = sd->pos;
-	ssize_t ret;
-	void *ptr;
-	int more;
+	int ret, more;
 
-	/*
-	 * Sub-optimal, but we are limited by the pipe ->map. We don't
-	 * need a kmap'ed buffer here, we just want to make sure we
-	 * have the page pinned if the pipe page originates from the
-	 * page cache.
-	 */
-	ptr = buf->ops->map(file, info, buf);
-	if (IS_ERR(ptr))
-		return PTR_ERR(ptr);
+	ret = buf->ops->pin(pipe, buf);
+	if (!ret) {
+		more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len;
 
-	more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len;
-
-	ret = file->f_op->sendpage(file, buf->page, buf->offset, sd->len,
-				   &pos, more);
+		ret = file->f_op->sendpage(file, buf->page, buf->offset,
+					   sd->len, &pos, more);
+	}
 
-	buf->ops->unmap(info, buf);
 	return ret;
 }
 
@@ -560,7 +552,7 @@ static int pipe_to_sendpage(struct pipe_inode_info *info,
  * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create
  * a new page in the output file page cache and fill/dirty that.
  */
-static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
+static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 			struct splice_desc *sd)
 {
 	struct file *file = sd->file;
@@ -569,15 +561,14 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
 	unsigned int offset, this_len;
 	struct page *page;
 	pgoff_t index;
-	char *src;
 	int ret;
 
 	/*
 	 * make sure the data in this buffer is uptodate
 	 */
-	src = buf->ops->map(file, info, buf);
-	if (IS_ERR(src))
-		return PTR_ERR(src);
+	ret = buf->ops->pin(pipe, buf);
+	if (unlikely(ret))
+		return ret;
 
 	index = sd->pos >> PAGE_CACHE_SHIFT;
 	offset = sd->pos & ~PAGE_CACHE_MASK;
@@ -587,20 +578,25 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
 		this_len = PAGE_CACHE_SIZE - offset;
 
 	/*
-	 * Reuse buf page, if SPLICE_F_MOVE is set.
+	 * Reuse buf page, if SPLICE_F_MOVE is set and we are doing a full
+	 * page.
 	 */
-	if (sd->flags & SPLICE_F_MOVE) {
+	if ((sd->flags & SPLICE_F_MOVE) && this_len == PAGE_CACHE_SIZE) {
 		/*
-		 * If steal succeeds, buf->page is now pruned from the vm
-		 * side (LRU and page cache) and we can reuse it. The page
-		 * will also be looked on successful return.
+		 * If steal succeeds, buf->page is now pruned from the
+		 * pagecache and we can reuse it. The page will also be
+		 * locked on successful return.
 		 */
-		if (buf->ops->steal(info, buf))
+		if (buf->ops->steal(pipe, buf))
 			goto find_page;
 
 		page = buf->page;
-		if (add_to_page_cache(page, mapping, index, gfp_mask))
+		if (add_to_page_cache(page, mapping, index, gfp_mask)) {
+			unlock_page(page);
 			goto find_page;
+		}
+
+		page_cache_get(page);
 
 		if (!(buf->flags & PIPE_BUF_FLAG_LRU))
 			lru_cache_add(page);
@@ -654,40 +650,55 @@ find_page:
 	}
 
 	ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len);
-	if (ret == AOP_TRUNCATED_PAGE) {
+	if (unlikely(ret)) {
+		loff_t isize = i_size_read(mapping->host);
+
+		if (ret != AOP_TRUNCATED_PAGE)
+			unlock_page(page);
 		page_cache_release(page);
-		goto find_page;
-	} else if (ret)
+		if (ret == AOP_TRUNCATED_PAGE)
+			goto find_page;
+
+		/*
+		 * prepare_write() may have instantiated a few blocks
+		 * outside i_size.  Trim these off again.
+		 */
+		if (sd->pos + this_len > isize)
+			vmtruncate(mapping->host, isize);
+
 		goto out;
+	}
 
-	if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) {
-		char *dst = kmap_atomic(page, KM_USER0);
+	if (buf->page != page) {
+		/*
+		 * Careful, ->map() uses KM_USER0!
+		 */
+		char *src = buf->ops->map(pipe, buf, 1);
+		char *dst = kmap_atomic(page, KM_USER1);
 
 		memcpy(dst + offset, src + buf->offset, this_len);
 		flush_dcache_page(page);
-		kunmap_atomic(dst, KM_USER0);
+		kunmap_atomic(dst, KM_USER1);
+		buf->ops->unmap(pipe, buf, src);
 	}
 
 	ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len);
-	if (ret == AOP_TRUNCATED_PAGE) {
+	if (!ret) {
+		/*
+		 * Return the number of bytes written and mark page as
+		 * accessed, we are now done!
+		 */
+		ret = this_len;
+		mark_page_accessed(page);
+		balance_dirty_pages_ratelimited(mapping);
+	} else if (ret == AOP_TRUNCATED_PAGE) {
 		page_cache_release(page);
 		goto find_page;
-	} else if (ret)
-		goto out;
-
-	/*
-	 * Return the number of bytes written.
-	 */
-	ret = this_len;
-	mark_page_accessed(page);
-	balance_dirty_pages_ratelimited(mapping);
+	}
 out:
-	if (!(buf->flags & PIPE_BUF_FLAG_STOLEN))
-		page_cache_release(page);
-
+	page_cache_release(page);
 	unlock_page(page);
 out_nomem:
-	buf->ops->unmap(info, buf);
 	return ret;
 }
 
@@ -1095,7 +1106,7 @@ static long do_splice(struct file *in, loff_t __user *off_in,
  */
 static int get_iovec_page_array(const struct iovec __user *iov,
 				unsigned int nr_vecs, struct page **pages,
-				struct partial_page *partial)
+				struct partial_page *partial, int aligned)
 {
 	int buffers = 0, error = 0;
 
@@ -1135,6 +1146,15 @@ static int get_iovec_page_array(const struct iovec __user *iov,
 		 * 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;
@@ -1150,7 +1170,7 @@ static int get_iovec_page_array(const struct iovec __user *iov,
 		 * 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;
+			const int plen = min_t(size_t, len, PAGE_SIZE - off);
 
 			partial[buffers].offset = off;
 			partial[buffers].len = plen;
@@ -1228,7 +1248,8 @@ static long do_vmsplice(struct file *file, const struct iovec __user *iov,
 	else if (unlikely(!nr_segs))
 		return 0;
 
-	spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial);
+	spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial,
+					    flags & SPLICE_F_GIFT);
 	if (spd.nr_pages <= 0)
 		return spd.nr_pages;
 
@@ -1285,6 +1306,85 @@ asmlinkage long sys_splice(int fd_in, loff_t __user *off_in,
 	return error;
 }
 
+/*
+ * Make sure there's data to read. Wait for input if we can, otherwise
+ * return an appropriate error.
+ */
+static int link_ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags)
+{
+	int ret;
+
+	/*
+	 * Check ->nrbufs without the inode lock first. This function
+	 * is speculative anyways, so missing one is ok.
+	 */
+	if (pipe->nrbufs)
+		return 0;
+
+	ret = 0;
+	mutex_lock(&pipe->inode->i_mutex);
+
+	while (!pipe->nrbufs) {
+		if (signal_pending(current)) {
+			ret = -ERESTARTSYS;
+			break;
+		}
+		if (!pipe->writers)
+			break;
+		if (!pipe->waiting_writers) {
+			if (flags & SPLICE_F_NONBLOCK) {
+				ret = -EAGAIN;
+				break;
+			}
+		}
+		pipe_wait(pipe);
+	}
+
+	mutex_unlock(&pipe->inode->i_mutex);
+	return ret;
+}
+
+/*
+ * Make sure there's writeable room. Wait for room if we can, otherwise
+ * return an appropriate error.
+ */
+static int link_opipe_prep(struct pipe_inode_info *pipe, unsigned int flags)
+{
+	int ret;
+
+	/*
+	 * Check ->nrbufs without the inode lock first. This function
+	 * is speculative anyways, so missing one is ok.
+	 */
+	if (pipe->nrbufs < PIPE_BUFFERS)
+		return 0;
+
+	ret = 0;
+	mutex_lock(&pipe->inode->i_mutex);
+
+	while (pipe->nrbufs >= PIPE_BUFFERS) {
+		if (!pipe->readers) {
+			send_sig(SIGPIPE, current, 0);
+			ret = -EPIPE;
+			break;
+		}
+		if (flags & SPLICE_F_NONBLOCK) {
+			ret = -EAGAIN;
+			break;
+		}
+		if (signal_pending(current)) {
+			ret = -ERESTARTSYS;
+			break;
+		}
+		pipe->waiting_writers++;
+		pipe_wait(pipe);
+		pipe->waiting_writers--;
+	}
+
+	mutex_unlock(&pipe->inode->i_mutex);
+	return ret;
+}
+
 /*
  * Link contents of ipipe to opipe.
  */
@@ -1293,9 +1393,7 @@ static int link_pipe(struct pipe_inode_info *ipipe,
 		     size_t len, unsigned int flags)
 {
 	struct pipe_buffer *ibuf, *obuf;
-	int ret, do_wakeup, i, ipipe_first;
-
-	ret = do_wakeup = ipipe_first = 0;
+	int ret = 0, i = 0, nbuf;
 
 	/*
 	 * Potential ABBA deadlock, work around it by ordering lock
@@ -1303,120 +1401,62 @@ static int link_pipe(struct pipe_inode_info *ipipe,
 	 * could deadlock (one doing tee from A -> B, the other from B -> A).
 	 */
 	if (ipipe->inode < opipe->inode) {
-		ipipe_first = 1;
-		mutex_lock(&ipipe->inode->i_mutex);
-		mutex_lock(&opipe->inode->i_mutex);
+		mutex_lock_nested(&ipipe->inode->i_mutex, I_MUTEX_PARENT);
+		mutex_lock_nested(&opipe->inode->i_mutex, I_MUTEX_CHILD);
 	} else {
-		mutex_lock(&opipe->inode->i_mutex);
-		mutex_lock(&ipipe->inode->i_mutex);
+		mutex_lock_nested(&opipe->inode->i_mutex, I_MUTEX_PARENT);
+		mutex_lock_nested(&ipipe->inode->i_mutex, I_MUTEX_CHILD);
 	}
 
-	for (i = 0;; i++) {
+	do {
 		if (!opipe->readers) {
 			send_sig(SIGPIPE, current, 0);
 			if (!ret)
 				ret = -EPIPE;
 			break;
 		}
-		if (ipipe->nrbufs - i) {
-			ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1));
-
-			/*
-			 * If we have room, fill this buffer
-			 */
-			if (opipe->nrbufs < PIPE_BUFFERS) {
-				int nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1);
 
-				/*
-				 * Get a reference to this pipe buffer,
-				 * so we can copy the contents over.
-				 */
-				ibuf->ops->get(ipipe, ibuf);
-
-				obuf = opipe->bufs + nbuf;
-				*obuf = *ibuf;
-
-				if (obuf->len > len)
-					obuf->len = len;
-
-				opipe->nrbufs++;
-				do_wakeup = 1;
-				ret += obuf->len;
-				len -= obuf->len;
-
-				if (!len)
-					break;
-				if (opipe->nrbufs < PIPE_BUFFERS)
-					continue;
-			}
-
-			/*
-			 * We have input available, but no output room.
-			 * If we already copied data, return that. If we
-			 * need to drop the opipe lock, it must be ordered
-			 * last to avoid deadlocks.
-			 */
-			if ((flags & SPLICE_F_NONBLOCK) || !ipipe_first) {
-				if (!ret)
-					ret = -EAGAIN;
-				break;
-			}
-			if (signal_pending(current)) {
-				if (!ret)
-					ret = -ERESTARTSYS;
-				break;
-			}
-			if (do_wakeup) {
-				smp_mb();
-				if (waitqueue_active(&opipe->wait))
-					wake_up_interruptible(&opipe->wait);
-				kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN);
-				do_wakeup = 0;
-			}
+		/*
+		 * If we have iterated all input buffers or ran out of
+		 * output room, break.
+		 */
+		if (i >= ipipe->nrbufs || opipe->nrbufs >= PIPE_BUFFERS)
+			break;
 
-			opipe->waiting_writers++;
-			pipe_wait(opipe);
-			opipe->waiting_writers--;
-			continue;
-		}
+		ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1));
+		nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1);
 
 		/*
-		 * No input buffers, do the usual checks for available
-		 * writers and blocking and wait if necessary
+		 * Get a reference to this pipe buffer,
+		 * so we can copy the contents over.
 		 */
-		if (!ipipe->writers)
-			break;
-		if (!ipipe->waiting_writers) {
-			if (ret)
-				break;
-		}
+		ibuf->ops->get(ipipe, ibuf);
+
+		obuf = opipe->bufs + nbuf;
+		*obuf = *ibuf;
+
 		/*
-		 * pipe_wait() drops the ipipe mutex. To avoid deadlocks
-		 * with another process, we can only safely do that if
-		 * the ipipe lock is ordered last.
+		 * Don't inherit the gift flag, we need to
+		 * prevent multiple steals of this page.
 		 */
-		if ((flags & SPLICE_F_NONBLOCK) || ipipe_first) {
-			if (!ret)
-				ret = -EAGAIN;
-			break;
-		}
-		if (signal_pending(current)) {
-			if (!ret)
-				ret = -ERESTARTSYS;
-			break;
-		}
+		obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
 
-		if (waitqueue_active(&ipipe->wait))
-			wake_up_interruptible_sync(&ipipe->wait);
-		kill_fasync(&ipipe->fasync_writers, SIGIO, POLL_OUT);
+		if (obuf->len > len)
+			obuf->len = len;
 
-		pipe_wait(ipipe);
-	}
+		opipe->nrbufs++;
+		ret += obuf->len;
+		len -= obuf->len;
+		i++;
+	} while (len);
 
 	mutex_unlock(&ipipe->inode->i_mutex);
 	mutex_unlock(&opipe->inode->i_mutex);
 
-	if (do_wakeup) {
+	/*
+	 * If we put data in the output pipe, wakeup any potential readers.
+	 */
+	if (ret > 0) {
 		smp_mb();
 		if (waitqueue_active(&opipe->wait))
 			wake_up_interruptible(&opipe->wait);
@@ -1437,14 +1477,29 @@ static long do_tee(struct file *in, struct file *out, size_t len,
 {
 	struct pipe_inode_info *ipipe = in->f_dentry->d_inode->i_pipe;
 	struct pipe_inode_info *opipe = out->f_dentry->d_inode->i_pipe;
+	int ret = -EINVAL;
 
 	/*
-	 * Link ipipe to the two output pipes, consuming as we go along.
+	 * Duplicate the contents of ipipe to opipe without actually
+	 * copying the data.
 	 */
-	if (ipipe && opipe)
-		return link_pipe(ipipe, opipe, len, flags);
+	if (ipipe && opipe && ipipe != opipe) {
+		/*
+		 * Keep going, unless we encounter an error. The ipipe/opipe
+		 * ordering doesn't really matter.
+		 */
+		ret = link_ipipe_prep(ipipe, flags);
+		if (!ret) {
+			ret = link_opipe_prep(opipe, flags);
+			if (!ret) {
+				ret = link_pipe(ipipe, opipe, len, flags);
+				if (!ret && (flags & SPLICE_F_NONBLOCK))
+					ret = -EAGAIN;
+			}
+		}
+	}
 
-	return -EINVAL;
+	return ret;
 }
 
 asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags)