Merge tag 'iomap-5.5-merge-13' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull iomap cleanups from Darrick Wong:
 "Aome more new iomap code for 5.5.

  There's not much this time -- just removing some local variables that
  don't need to exist in the iomap directio code"

* tag 'iomap-5.5-merge-13' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  iomap: remove unneeded variable in iomap_dio_rw()
  iomap: Do not create fake iter in iomap_dio_bio_actor()

Author: torvalds

fs/iomap/direct-io.c

@@ -201,12 +201,12 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length,
 	unsigned int blkbits = blksize_bits(bdev_logical_block_size(iomap->bdev));
 	unsigned int fs_block_size = i_blocksize(inode), pad;
 	unsigned int align = iov_iter_alignment(dio->submit.iter);
-	struct iov_iter iter;
 	struct bio *bio;
 	bool need_zeroout = false;
 	bool use_fua = false;
 	int nr_pages, ret = 0;
 	size_t copied = 0;
+	size_t orig_count;
 
 	if ((pos | length | align) & ((1 << blkbits) - 1))
 		return -EINVAL;
@@ -236,15 +236,18 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length,
 	}
 
 	/*
-	 * Operate on a partial iter trimmed to the extent we were called for.
-	 * We'll update the iter in the dio once we're done with this extent.
+	 * Save the original count and trim the iter to just the extent we
+	 * are operating on right now.  The iter will be re-expanded once
+	 * we are done.
 	 */
-	iter = *dio->submit.iter;
-	iov_iter_truncate(&iter, length);
+	orig_count = iov_iter_count(dio->submit.iter);
+	iov_iter_truncate(dio->submit.iter, length);
 
-	nr_pages = iov_iter_npages(&iter, BIO_MAX_PAGES);
-	if (nr_pages <= 0)
-		return nr_pages;
+	nr_pages = iov_iter_npages(dio->submit.iter, BIO_MAX_PAGES);
+	if (nr_pages <= 0) {
+		ret = nr_pages;
+		goto out;
+	}
 
 	if (need_zeroout) {
 		/* zero out from the start of the block to the write offset */
@@ -257,7 +260,8 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length,
 		size_t n;
 		if (dio->error) {
 			iov_iter_revert(dio->submit.iter, copied);
-			return 0;
+			copied = ret = 0;
+			goto out;
 		}
 
 		bio = bio_alloc(GFP_KERNEL, nr_pages);
@@ -268,7 +272,7 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length,
 		bio->bi_private = dio;
 		bio->bi_end_io = iomap_dio_bio_end_io;
 
-		ret = bio_iov_iter_get_pages(bio, &iter);
+		ret = bio_iov_iter_get_pages(bio, dio->submit.iter);
 		if (unlikely(ret)) {
 			/*
 			 * We have to stop part way through an IO. We must fall
@@ -294,13 +298,11 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length,
 				bio_set_pages_dirty(bio);
 		}
 
-		iov_iter_advance(dio->submit.iter, n);
-
 		dio->size += n;
 		pos += n;
 		copied += n;
 
-		nr_pages = iov_iter_npages(&iter, BIO_MAX_PAGES);
+		nr_pages = iov_iter_npages(dio->submit.iter, BIO_MAX_PAGES);
 		iomap_dio_submit_bio(dio, iomap, bio);
 	} while (nr_pages);
 
@@ -318,6 +320,9 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length,
 		if (pad)
 			iomap_dio_zero(dio, iomap, pos, fs_block_size - pad);
 	}
+out:
+	/* Undo iter limitation to current extent */
+	iov_iter_reexpand(dio->submit.iter, orig_count - copied);
 	if (copied)
 		return copied;
 	return ret;
@@ -400,7 +405,7 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 	struct address_space *mapping = iocb->ki_filp->f_mapping;
 	struct inode *inode = file_inode(iocb->ki_filp);
 	size_t count = iov_iter_count(iter);
-	loff_t pos = iocb->ki_pos, start = pos;
+	loff_t pos = iocb->ki_pos;
 	loff_t end = iocb->ki_pos + count - 1, ret = 0;
 	unsigned int flags = IOMAP_DIRECT;
 	struct blk_plug plug;
@@ -456,14 +461,14 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 	}
 
 	if (iocb->ki_flags & IOCB_NOWAIT) {
-		if (filemap_range_has_page(mapping, start, end)) {
+		if (filemap_range_has_page(mapping, pos, end)) {
 			ret = -EAGAIN;
 			goto out_free_dio;
 		}
 		flags |= IOMAP_NOWAIT;
 	}
 
-	ret = filemap_write_and_wait_range(mapping, start, end);
+	ret = filemap_write_and_wait_range(mapping, pos, end);
 	if (ret)
 		goto out_free_dio;
 
@@ -474,7 +479,7 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 	 * pretty crazy thing to do, so we don't support it 100%.
 	 */
 	ret = invalidate_inode_pages2_range(mapping,
-			start >> PAGE_SHIFT, end >> PAGE_SHIFT);
+			pos >> PAGE_SHIFT, end >> PAGE_SHIFT);
 	if (ret)
 		dio_warn_stale_pagecache(iocb->ki_filp);
 	ret = 0;