[PATCH 1/7] dm: Replace __HIGH() and __LOW() macros

From: Joe Thornber (thornber@sistina.com)
Date: Mon Jun 09 2003 - 09:34:40 EST


Replace __HIGH() and __LOW() with max() and min_not_zero().
--- diff/drivers/md/dm-table.c 2003-05-21 11:50:15.000000000 +0100
+++ source/drivers/md/dm-table.c 2003-06-09 15:04:57.000000000 +0100
@@ -78,22 +78,33 @@
         return result;
 }
 
-#define __HIGH(l, r) if (*(l) < (r)) *(l) = (r)
-#define __LOW(l, r) if (*(l) == 0 || *(l) > (r)) *(l) = (r)
+/*
+ * Returns the minimum that is _not_ zero, unless both are zero.
+ */
+#define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r))
 
 /*
  * Combine two io_restrictions, always taking the lower value.
  */
-
 static void combine_restrictions_low(struct io_restrictions *lhs,
                                      struct io_restrictions *rhs)
 {
- __LOW(&lhs->max_sectors, rhs->max_sectors);
- __LOW(&lhs->max_phys_segments, rhs->max_phys_segments);
- __LOW(&lhs->max_hw_segments, rhs->max_hw_segments);
- __HIGH(&lhs->hardsect_size, rhs->hardsect_size);
- __LOW(&lhs->max_segment_size, rhs->max_segment_size);
- __LOW(&lhs->seg_boundary_mask, rhs->seg_boundary_mask);
+ lhs->max_sectors =
+ min_not_zero(lhs->max_sectors, rhs->max_sectors);
+
+ lhs->max_phys_segments =
+ min_not_zero(lhs->max_phys_segments, rhs->max_phys_segments);
+
+ lhs->max_hw_segments =
+ min_not_zero(lhs->max_hw_segments, rhs->max_hw_segments);
+
+ lhs->hardsect_size = max(lhs->hardsect_size, rhs->hardsect_size);
+
+ lhs->max_segment_size =
+ min_not_zero(lhs->max_segment_size, rhs->max_segment_size);
+
+ lhs->seg_boundary_mask =
+ min_not_zero(lhs->seg_boundary_mask, rhs->seg_boundary_mask);
 }
 
 /*
@@ -481,13 +492,31 @@
                 request_queue_t *q = bdev_get_queue((*result)->bdev);
                 struct io_restrictions *rs = &ti->limits;
 
- /* combine the device limits low */
- __LOW(&rs->max_sectors, q->max_sectors);
- __LOW(&rs->max_phys_segments, q->max_phys_segments);
- __LOW(&rs->max_hw_segments, q->max_hw_segments);
- __HIGH(&rs->hardsect_size, q->hardsect_size);
- __LOW(&rs->max_segment_size, q->max_segment_size);
- __LOW(&rs->seg_boundary_mask, q->seg_boundary_mask);
+ /*
+ * Combine the device limits low.
+ *
+ * FIXME: if we move an io_restriction struct
+ * into q this would just be a call to
+ * combine_restrictions_low()
+ */
+ rs->max_sectors =
+ min_not_zero(rs->max_sectors, q->max_sectors);
+
+ rs->max_phys_segments =
+ min_not_zero(rs->max_phys_segments,
+ q->max_phys_segments);
+
+ rs->max_hw_segments =
+ min_not_zero(rs->max_hw_segments, q->max_hw_segments);
+
+ rs->hardsect_size = max(rs->hardsect_size, q->hardsect_size);
+
+ rs->max_segment_size =
+ min_not_zero(rs->max_segment_size, q->max_segment_size);
+
+ rs->seg_boundary_mask =
+ min_not_zero(rs->seg_boundary_mask,
+ q->seg_boundary_mask);
         }
 
         return r;
-
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