Another fix for the __LOW macro. When dm_table and dm_target structures are initialized, the "limits" fields (struct io_restrictions) are initialized to zero (e.g. in dm_table_add_target() in dm-table.c). However, zero is not a useable value in these fields. The request queue will never let an I/O through, regardless of how small it might be, if max_sectors is set to zero (see generic_make_request in ll_rw_blk.c). This change to the __LOW() macro sets these fields correctly when they are first initialized. --- linux-2.5.59a/drivers/md/dm-table.c 2003/01/10 21:34:54 +++ linux-2.5.59b/drivers/md/dm-table.c 2003/02/04 22:14:26 @@ -79,7 +79,7 @@ } #define __HIGH(l, r) if (*(l) < (r)) *(l) = (r) -#define __LOW(l, r) if (*(l) > (r)) *(l) = (r) +#define __LOW(l, r) if (*(l) == 0 || *(l) > (r)) *(l) = (r) /* * Combine two io_restrictions, always taking the lower value.
