f2fs: bug fix on bit overflow from 32bits to 64bits

This patch fixes some bit overflows by the shift operations.

Dan Carpenter reported potential bugs on bit overflows as follows.

fs/f2fs/segment.c:910 submit_write_page()
	warn: should 'blk_addr << ((sbi)->log_blocksize - 9)' be a 64 bit type?
fs/f2fs/checkpoint.c:429 get_valid_checkpoint()
	warn: should '1 << ()' be a 64 bit type?
fs/f2fs/data.c:408 f2fs_readpage()
	warn: should 'blk_addr << ((sbi)->log_blocksize - 9)' be a 64 bit type?
fs/f2fs/data.c:457 submit_read_page()
	warn: should 'blk_addr << ((sbi)->log_blocksize - 9)' be a 64 bit type?
fs/f2fs/data.c:525 get_data_block_ro()
	warn: should 'i << blkbits' be a 64 bit type?

Bug-Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 1e837139..0387863 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -270,8 +270,8 @@
 static void f2fs_issue_discard(struct f2fs_sb_info *sbi,
 				block_t blkstart, block_t blklen)
 {
-	sector_t start = ((sector_t)blkstart) << sbi->log_sectors_per_block;
-	sector_t len = ((sector_t)blklen) << sbi->log_sectors_per_block;
+	sector_t start = SECTOR_FROM_BLOCK(sbi, blkstart);
+	sector_t len = SECTOR_FROM_BLOCK(sbi, blklen);
 	blkdev_issue_discard(sbi->sb->s_bdev, start, len, GFP_NOFS, 0);
 	trace_f2fs_issue_discard(sbi->sb, blkstart, blklen);
 }