ext4: use sizeof(*ptr)

Replace the specification of data structures by pointer dereferences
as the parameter for the operator "sizeof" to make the corresponding size
determination a bit safer according to the Linux coding style convention.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <[e-mail]>
Signed-off-by: Theodore Ts'o <[e-mail]>
Reviewed-by: Eric Sandeen <[e-mail]>

fs/ext4/dir.c

···
 {
 	struct dir_private_info *p;
 
-	p = kzalloc(sizeof(struct dir_private_info), GFP_KERNEL);
+	p = kzalloc(sizeof(*p), GFP_KERNEL);
 	if (!p)
 		return NULL;
 	p->curr_hash = pos2maj_hash(filp, pos);

fs/ext4/mmp.c

···
 		goto failed;
 	}
 
-	mmpd_data = kmalloc(sizeof(struct mmpd_data), GFP_KERNEL);
+	mmpd_data = kmalloc(sizeof(*mmpd_data), GFP_KERNEL);
 	if (!mmpd_data) {
 		ext4_warning(sb, "not enough memory for mmpd_data");
 		goto failed;