1 files changed, 28 insertions, 51 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index 70273f8df586..8f1a95406bae 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1402,13 +1402,25 @@ shmem_write_end(struct file *file, struct address_space *mapping,
 	return copied;
 }
 
-static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor)
+static ssize_t shmem_file_aio_read(struct kiocb *iocb,
+		const struct iovec *iov, unsigned long nr_segs, loff_t pos)
 {
-	struct inode *inode = file_inode(filp);
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = file_inode(file);
 	struct address_space *mapping = inode->i_mapping;
 	pgoff_t index;
 	unsigned long offset;
 	enum sgp_type sgp = SGP_READ;
+	int error;
+	ssize_t retval;
+	size_t count;
+	loff_t *ppos = &iocb->ki_pos;
+	struct iov_iter iter;
+
+	retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);
+	if (retval)
+		return retval;
+	iov_iter_init(&iter, iov, nr_segs, count, 0);
 
 	/*
 	 * Might this read be for a stacking filesystem?  Then when reading
@@ -1436,10 +1448,10 @@ static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_
 				break;
 		}
 
-		desc->error = shmem_getpage(inode, index, &page, sgp, NULL);
-		if (desc->error) {
-			if (desc->error == -EINVAL)
-				desc->error = 0;
+		error = shmem_getpage(inode, index, &page, sgp, NULL);
+		if (error) {
+			if (error == -EINVAL)
+				error = 0;
 			break;
 		}
 		if (page)
@@ -1483,61 +1495,26 @@ static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_
 		/*
 		 * Ok, we have the page, and it's up-to-date, so
 		 * now we can copy it to user space...
-		 *
-		 * The actor routine returns how many bytes were actually used..
-		 * NOTE! This may not be the same as how much of a user buffer
-		 * we filled up (we may be padding etc), so we can only update
-		 * "pos" here (the actor routine has to update the user buffer
-		 * pointers and the remaining count).
 		 */
-		ret = actor(desc, page, offset, nr);
+		ret = copy_page_to_iter(page, offset, nr, &iter);
+		retval += ret;
 		offset += ret;
 		index += offset >> PAGE_CACHE_SHIFT;
 		offset &= ~PAGE_CACHE_MASK;
 
 		page_cache_release(page);
-		if (ret != nr || !desc->count)
+		if (!iov_iter_count(&iter))
 			break;
-
+		if (ret < nr) {
+			error = -EFAULT;
+			break;
+		}
 		cond_resched();
 	}
 
 	*ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset;
-	file_accessed(filp);
-}
-
-static ssize_t shmem_file_aio_read(struct kiocb *iocb,
-		const struct iovec *iov, unsigned long nr_segs, loff_t pos)
-{
-	struct file *filp = iocb->ki_filp;
-	ssize_t retval;
-	unsigned long seg;
-	size_t count;
-	loff_t *ppos = &iocb->ki_pos;
-
-	retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);
-	if (retval)
-		return retval;
-
-	for (seg = 0; seg < nr_segs; seg++) {
-		read_descriptor_t desc;
-
-		desc.written = 0;
-		desc.arg.buf = iov[seg].iov_base;
-		desc.count = iov[seg].iov_len;
-		if (desc.count == 0)
-			continue;
-		desc.error = 0;
-		do_shmem_file_read(filp, ppos, &desc, file_read_actor);
-		retval += desc.written;
-		if (desc.error) {
-			retval = retval ?: desc.error;
-			break;
-		}
-		if (desc.count > 0)
-			break;
-	}
-	return retval;
+	file_accessed(file);
+	return retval ? retval : error;
 }
 
 static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos,
@@ -1576,7 +1553,7 @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos,
 	index = *ppos >> PAGE_CACHE_SHIFT;
 	loff = *ppos & ~PAGE_CACHE_MASK;
 	req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
-	nr_pages = min(req_pages, pipe->buffers);
+	nr_pages = min(req_pages, spd.nr_pages_max);
 
 	spd.nr_pages = find_get_pages_contig(mapping, index,
 						nr_pages, spd.pages);