btrfs: get rid of sector_t and use u64 offset in submit_extent_page

The use of sector_t in the callchain of submit_extent_page is not
necessary.  Switch to u64 and rename the variable and use byte units
instead of 512b, ie.  dropping the >> 9 shifts and avoiding the
con(tro)versions of sector_t.
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/extent_io.c

@@ -2760,7 +2760,7 @@ static int merge_bio(struct extent_io_tree *tree, struct page *page,
  */
 static int submit_extent_page(unsigned int opf, struct extent_io_tree *tree,
 			      struct writeback_control *wbc,
-			      struct page *page, sector_t sector,
+			      struct page *page, u64 offset,
 			      size_t size, unsigned long pg_offset,
 			      struct block_device *bdev,
 			      struct bio **bio_ret,
@@ -2775,6 +2775,7 @@ static int submit_extent_page(unsigned int opf, struct extent_io_tree *tree,
 	int contig = 0;
 	int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
 	size_t page_size = min_t(size_t, size, PAGE_SIZE);
+	sector_t sector = offset >> 9;
 
 	if (bio_ret && *bio_ret) {
 		bio = *bio_ret;
@@ -2800,7 +2801,7 @@ static int submit_extent_page(unsigned int opf, struct extent_io_tree *tree,
 		}
 	}
 
-	bio = btrfs_bio_alloc(bdev, (u64)sector << 9);
+	bio = btrfs_bio_alloc(bdev, offset);
 	bio_add_page(bio, page, page_size, pg_offset);
 	bio->bi_end_io = end_io_func;
 	bio->bi_private = tree;
@@ -2891,7 +2892,6 @@ static int __do_readpage(struct extent_io_tree *tree,
 	u64 last_byte = i_size_read(inode);
 	u64 block_start;
 	u64 cur_end;
-	sector_t sector;
 	struct extent_map *em;
 	struct block_device *bdev;
 	int ret = 0;
@@ -2927,6 +2927,7 @@ static int __do_readpage(struct extent_io_tree *tree,
 	}
 	while (cur <= end) {
 		bool force_bio_submit = false;
+		u64 offset;
 
 		if (cur >= last_byte) {
 			char *userpage;
@@ -2966,9 +2967,9 @@ static int __do_readpage(struct extent_io_tree *tree,
 		iosize = ALIGN(iosize, blocksize);
 		if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
 			disk_io_size = em->block_len;
-			sector = em->block_start >> 9;
+			offset = em->block_start;
 		} else {
-			sector = (em->block_start + extent_offset) >> 9;
+			offset = em->block_start + extent_offset;
 			disk_io_size = iosize;
 		}
 		bdev = em->bdev;
@@ -3061,8 +3062,8 @@ static int __do_readpage(struct extent_io_tree *tree,
 		}
 
 		ret = submit_extent_page(REQ_OP_READ | read_flags, tree, NULL,
-					 page, sector, disk_io_size, pg_offset,
-					 bdev, bio,
+					 page, offset, disk_io_size,
+					 pg_offset, bdev, bio,
 					 end_bio_extent_readpage, mirror_num,
 					 *bio_flags,
 					 this_bio_flag,
@@ -3323,7 +3324,6 @@ static noinline_for_stack int __extent_writepage_io(struct inode *inode,
 	u64 extent_offset;
 	u64 block_start;
 	u64 iosize;
-	sector_t sector;
 	struct extent_map *em;
 	struct block_device *bdev;
 	size_t pg_offset = 0;
@@ -3366,6 +3366,7 @@ static noinline_for_stack int __extent_writepage_io(struct inode *inode,
 
 	while (cur <= end) {
 		u64 em_end;
+		u64 offset;
 
 		if (cur >= i_size) {
 			if (tree->ops && tree->ops->writepage_end_io_hook)
@@ -3387,7 +3388,7 @@ static noinline_for_stack int __extent_writepage_io(struct inode *inode,
 		BUG_ON(end < cur);
 		iosize = min(em_end - cur, end - cur + 1);
 		iosize = ALIGN(iosize, blocksize);
-		sector = (em->block_start + extent_offset) >> 9;
+		offset = em->block_start + extent_offset;
 		bdev = em->bdev;
 		block_start = em->block_start;
 		compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
@@ -3430,7 +3431,7 @@ static noinline_for_stack int __extent_writepage_io(struct inode *inode,
 		}
 
 		ret = submit_extent_page(REQ_OP_WRITE | write_flags, tree, wbc,
-					 page, sector, iosize, pg_offset,
+					 page, offset, iosize, pg_offset,
 					 bdev, &epd->bio,
 					 end_bio_extent_writepage,
 					 0, 0, 0, false);
@@ -3744,7 +3745,7 @@ static noinline_for_stack int write_one_eb(struct extent_buffer *eb,
 		clear_page_dirty_for_io(p);
 		set_page_writeback(p);
 		ret = submit_extent_page(REQ_OP_WRITE | write_flags, tree, wbc,
-					 p, offset >> 9, PAGE_SIZE, 0, bdev,
+					 p, offset, PAGE_SIZE, 0, bdev,
 					 &epd->bio,
 					 end_bio_extent_buffer_writepage,
 					 0, 0, 0, false);