gfs2: Minor PAGE_SIZE arithmetic cleanups

Replace divisions by PAGE_SIZE with shifts by PAGE_SHIFT and similar.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

fs/gfs2/aops.c

@@ -243,7 +243,7 @@ static int gfs2_write_jdata_pagevec(struct address_space *mapping,
 {
 	struct inode *inode = mapping->host;
 	struct gfs2_sbd *sdp = GFS2_SB(inode);
-	unsigned nrblocks = nr_pages * (PAGE_SIZE/inode->i_sb->s_blocksize);
+	unsigned nrblocks = nr_pages * (PAGE_SIZE >> inode->i_blkbits);
 	int i;
 	int ret;
 
@@ -552,7 +552,7 @@ int gfs2_internal_read(struct gfs2_inode *ip, char *buf, loff_t *pos,
                        unsigned size)
 {
 	struct address_space *mapping = ip->i_inode.i_mapping;
-	unsigned long index = *pos / PAGE_SIZE;
+	unsigned long index = *pos >> PAGE_SHIFT;
 	unsigned offset = *pos & (PAGE_SIZE - 1);
 	unsigned copied = 0;
 	unsigned amt;

fs/gfs2/file.c

@@ -1049,7 +1049,7 @@ static long __gfs2_fallocate(struct file *file, int mode, loff_t offset, loff_t
 			rblocks += data_blocks ? data_blocks : 1;
 
 		error = gfs2_trans_begin(sdp, rblocks,
-					 PAGE_SIZE/sdp->sd_sb.sb_bsize);
+					 PAGE_SIZE >> inode->i_blkbits);
 		if (error)
 			goto out_trans_fail;
 

fs/gfs2/quota.c

@@ -774,7 +774,7 @@ static int gfs2_write_disk_quota(struct gfs2_inode *ip, struct gfs2_quota *qp,
 	nbytes = sizeof(struct gfs2_quota);
 
 	pg_beg = loc >> PAGE_SHIFT;
-	pg_off = loc % PAGE_SIZE;
+	pg_off = offset_in_page(loc);
 
 	/* If the quota straddles a page boundary, split the write in two */
 	if ((pg_off + nbytes) > PAGE_SIZE) {