1 files changed, 42 insertions, 116 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 7fadf1c62838..dafb06f70a09 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1665,96 +1665,42 @@ out:
 	return written ? written : error;
 }
 
-/*
- * Performs necessary checks before doing a write
- * @iov:	io vector request
- * @nr_segs:	number of segments in the iovec
- * @count:	number of bytes to write
- * @access_flags: type of access: %VERIFY_READ or %VERIFY_WRITE
- *
- * Adjust number of segments and amount of bytes to write (nr_segs should be
- * properly initialized first). Returns appropriate error code that caller
- * should return or zero in case that write should be allowed.
- */
-int generic_segment_checks(const struct iovec *iov,
-			unsigned long *nr_segs, size_t *count, int access_flags)
-{
-	unsigned long   seg;
-	size_t cnt = 0;
-	for (seg = 0; seg < *nr_segs; seg++) {
-		const struct iovec *iv = &iov[seg];
-
-		/*
-		 * If any segment has a negative length, or the cumulative
-		 * length ever wraps negative then return -EINVAL.
-		 */
-		cnt += iv->iov_len;
-		if (unlikely((ssize_t)(cnt|iv->iov_len) < 0))
-			return -EINVAL;
-		if (access_ok(access_flags, iv->iov_base, iv->iov_len))
-			continue;
-		if (seg == 0)
-			return -EFAULT;
-		*nr_segs = seg;
-		cnt -= iv->iov_len;	/* This segment is no good */
-		break;
-	}
-	*count = cnt;
-	return 0;
-}
-EXPORT_SYMBOL(generic_segment_checks);
-
 /**
- * generic_file_aio_read - generic filesystem read routine
+ * generic_file_read_iter - generic filesystem read routine
  * @iocb:	kernel I/O control block
- * @iov:	io vector request
- * @nr_segs:	number of segments in the iovec
- * @pos:	current file position
+ * @iter:	destination for the data read
  *
- * This is the "read()" routine for all filesystems
+ * This is the "read_iter()" routine for all filesystems
  * that can use the page cache directly.
  */
 ssize_t
-generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
-		unsigned long nr_segs, loff_t pos)
+generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 {
-	struct file *filp = iocb->ki_filp;
-	ssize_t retval;
-	size_t count;
+	struct file *file = iocb->ki_filp;
+	ssize_t retval = 0;
 	loff_t *ppos = &iocb->ki_pos;
-	struct iov_iter i;
-
-	count = 0;
-	retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);
-	if (retval)
-		return retval;
-	iov_iter_init(&i, iov, nr_segs, count, 0);
+	loff_t pos = *ppos;
 
 	/* coalesce the iovecs and go direct-to-BIO for O_DIRECT */
-	if (filp->f_flags & O_DIRECT) {
+	if (file->f_flags & O_DIRECT) {
+		struct address_space *mapping = file->f_mapping;
+		struct inode *inode = mapping->host;
+		size_t count = iov_iter_count(iter);
 		loff_t size;
-		struct address_space *mapping;
-		struct inode *inode;
 
-		mapping = filp->f_mapping;
-		inode = mapping->host;
 		if (!count)
 			goto out; /* skip atime */
 		size = i_size_read(inode);
 		retval = filemap_write_and_wait_range(mapping, pos,
-					pos + iov_length(iov, nr_segs) - 1);
+					pos + count - 1);
 		if (!retval) {
-			retval = mapping->a_ops->direct_IO(READ, iocb,
-							   iov, pos, nr_segs);
+			struct iov_iter data = *iter;
+			retval = mapping->a_ops->direct_IO(READ, iocb, &data, pos);
 		}
+
 		if (retval > 0) {
 			*ppos = pos + retval;
-			count -= retval;
-			/*
-			 * If we did a short DIO read we need to skip the
-			 * section of the iov that we've already read data into.
-			 */
-			iov_iter_advance(&i, retval);
+			iov_iter_advance(iter, retval);
 		}
 
 		/*
@@ -1765,17 +1711,17 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
 		 * and return.  Otherwise fallthrough to buffered io for
 		 * the rest of the read.
 		 */
-		if (retval < 0 || !count || *ppos >= size) {
-			file_accessed(filp);
+		if (retval < 0 || !iov_iter_count(iter) || *ppos >= size) {
+			file_accessed(file);
 			goto out;
 		}
 	}
 
-	retval = do_generic_file_read(filp, ppos, &i, retval);
+	retval = do_generic_file_read(file, ppos, iter, retval);
 out:
 	return retval;
 }
-EXPORT_SYMBOL(generic_file_aio_read);
+EXPORT_SYMBOL(generic_file_read_iter);
 
 #ifdef CONFIG_MMU
 /**
@@ -2386,9 +2332,7 @@ int pagecache_write_end(struct file *file, struct address_space *mapping,
 EXPORT_SYMBOL(pagecache_write_end);
 
 ssize_t
-generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
-		unsigned long *nr_segs, loff_t pos,
-		size_t count, size_t ocount)
+generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos)
 {
 	struct file	*file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
@@ -2396,11 +2340,9 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
 	ssize_t		written;
 	size_t		write_len;
 	pgoff_t		end;
+	struct iov_iter data;
 
-	if (count != ocount)
-		*nr_segs = iov_shorten((struct iovec *)iov, *nr_segs, count);
-
-	write_len = iov_length(iov, *nr_segs);
+	write_len = iov_iter_count(from);
 	end = (pos + write_len - 1) >> PAGE_CACHE_SHIFT;
 
 	written = filemap_write_and_wait_range(mapping, pos, pos + write_len - 1);
@@ -2427,7 +2369,8 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
 		}
 	}
 
-	written = mapping->a_ops->direct_IO(WRITE, iocb, iov, pos, *nr_segs);
+	data = *from;
+	written = mapping->a_ops->direct_IO(WRITE, iocb, &data, pos);
 
 	/*
 	 * Finally, try again to invalidate clean pages which might have been
@@ -2444,6 +2387,7 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
 
 	if (written > 0) {
 		pos += written;
+		iov_iter_advance(from, written);
 		if (pos > i_size_read(inode) && !S_ISBLK(inode->i_mode)) {
 			i_size_write(inode, pos);
 			mark_inode_dirty(inode);
@@ -2568,10 +2512,9 @@ again:
 EXPORT_SYMBOL(generic_perform_write);
 
 /**
- * __generic_file_aio_write - write data to a file
+ * __generic_file_write_iter - write data to a file
  * @iocb:	IO state structure (file, offset, etc.)
- * @iov:	vector with data to write
- * @nr_segs:	number of segments in the vector
+ * @from:	iov_iter with data to write
  *
  * This function does all the work needed for actually writing data to a
  * file. It does all basic checks, removes SUID from the file, updates
@@ -2585,26 +2528,16 @@ EXPORT_SYMBOL(generic_perform_write);
  * A caller has to handle it. This is mainly due to the fact that we want to
  * avoid syncing under i_mutex.
  */
-ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
-				 unsigned long nr_segs)
+ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space * mapping = file->f_mapping;
-	size_t ocount;		/* original count */
-	size_t count;		/* after file limit checks */
 	struct inode 	*inode = mapping->host;
 	loff_t		pos = iocb->ki_pos;
 	ssize_t		written = 0;
 	ssize_t		err;
 	ssize_t		status;
-	struct iov_iter from;
-
-	ocount = 0;
-	err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
-	if (err)
-		return err;
-
-	count = ocount;
+	size_t		count = iov_iter_count(from);
 
 	/* We can write back this queue in page reclaim */
 	current->backing_dev_info = mapping->backing_dev_info;
@@ -2615,6 +2548,8 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 	if (count == 0)
 		goto out;
 
+	iov_iter_truncate(from, count);
+
 	err = file_remove_suid(file);
 	if (err)
 		goto out;
@@ -2623,17 +2558,13 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 	if (err)
 		goto out;
 
-	iov_iter_init(&from, iov, nr_segs, count, 0);
-
 	/* coalesce the iovecs and go direct-to-BIO for O_DIRECT */
 	if (unlikely(file->f_flags & O_DIRECT)) {
 		loff_t endbyte;
 
-		written = generic_file_direct_write(iocb, iov, &from.nr_segs, pos,
-							count, ocount);
+		written = generic_file_direct_write(iocb, from, pos);
 		if (written < 0 || written == count)
 			goto out;
-		iov_iter_advance(&from, written);
 
 		/*
 		 * direct-io write to a hole: fall through to buffered I/O
@@ -2642,7 +2573,7 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 		pos += written;
 		count -= written;
 
-		status = generic_perform_write(file, &from, pos);
+		status = generic_perform_write(file, from, pos);
 		/*
 		 * If generic_perform_write() returned a synchronous error
 		 * then we want to return the number of bytes which were
@@ -2674,7 +2605,7 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 			 */
 		}
 	} else {
-		written = generic_perform_write(file, &from, pos);
+		written = generic_perform_write(file, from, pos);
 		if (likely(written >= 0))
 			iocb->ki_pos = pos + written;
 	}
@@ -2682,30 +2613,25 @@ out:
 	current->backing_dev_info = NULL;
 	return written ? written : err;
 }
-EXPORT_SYMBOL(__generic_file_aio_write);
+EXPORT_SYMBOL(__generic_file_write_iter);
 
 /**
- * generic_file_aio_write - write data to a file
+ * generic_file_write_iter - write data to a file
  * @iocb:	IO state structure
- * @iov:	vector with data to write
- * @nr_segs:	number of segments in the vector
- * @pos:	position in file where to write
+ * @from:	iov_iter with data to write
  *
- * This is a wrapper around __generic_file_aio_write() to be used by most
+ * This is a wrapper around __generic_file_write_iter() to be used by most
  * filesystems. It takes care of syncing the file in case of O_SYNC file
  * and acquires i_mutex as needed.
  */
-ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
-		unsigned long nr_segs, loff_t pos)
+ssize_t generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
 	ssize_t ret;
 
-	BUG_ON(iocb->ki_pos != pos);
-
 	mutex_lock(&inode->i_mutex);
-	ret = __generic_file_aio_write(iocb, iov, nr_segs);
+	ret = __generic_file_write_iter(iocb, from);
 	mutex_unlock(&inode->i_mutex);
 
 	if (ret > 0) {
@@ -2717,7 +2643,7 @@ ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 	}
 	return ret;
 }
-EXPORT_SYMBOL(generic_file_aio_write);
+EXPORT_SYMBOL(generic_file_write_iter);
 
 /**
  * try_to_release_page() - release old fs-specific metadata on a page