net/mlx5: Add MLX5_ARRAY_SET64 to fix BUILD_BUG_ON

I am hitting this in mlx5:

drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c: In function
reclaim_pages_cmd.clone.0:
drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c:346: error: call
to __compiletime_assert_346 declared with attribute error:
BUILD_BUG_ON failed: __mlx5_bit_off(manage_pages_out, pas[i]) % 64
drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c: In function give_pages:
drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c:291: error: call
to __compiletime_assert_291 declared with attribute error:
BUILD_BUG_ON failed: __mlx5_bit_off(manage_pages_in, pas[i]) % 64

Problem is that this is doing a BUILD_BUG_ON on a non-constant
expression because of trying to take offset of pas[i] in the
structure.

Fix is to create MLX5_ARRAY_SET64 that takes an additional argument
that is the field index to separate between BUILD_BUG_ON on the array
constant field and the indexed field to assign the value to.
There are two callers of MLX5_SET64 that are trying to get a variable
offset, change those to call MLX5_ARRAY_SET64 passing 'pas' and 'i'
as the arguments to use in the offset check and the indexed value
assignment.

Fixes: a533ed5e179cd ("net/mlx5: Pages management commands via mlx5 ifc")
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 2 deletions

diff --git a/include/linux/mlx5/device.h b/include/linux/mlx5/device.h
index 77c141797152..58276144ba81 100644
--- a/include/linux/mlx5/device.h
+++ b/include/linux/mlx5/device.h
@@ -92,12 +92,21 @@ __mlx5_mask(typ, fld))
         ___t; \
 })
 
-#define MLX5_SET64(typ, p, fld, v) do { \
+#define __MLX5_SET64(typ, p, fld, v) do { \
         BUILD_BUG_ON(__mlx5_bit_sz(typ, fld) != 64); \
-        BUILD_BUG_ON(__mlx5_bit_off(typ, fld) % 64); \
         *((__be64 *)(p) + __mlx5_64_off(typ, fld)) = cpu_to_be64(v); \
 } while (0)
 
+#define MLX5_SET64(typ, p, fld, v) do { \
+        BUILD_BUG_ON(__mlx5_bit_off(typ, fld) % 64); \
+        __MLX5_SET64(typ, p, fld, v); \
+} while (0)
+
+#define MLX5_ARRAY_SET64(typ, p, fld, idx, v) do { \
+        BUILD_BUG_ON(__mlx5_bit_off(typ, fld) % 64); \
+        __MLX5_SET64(typ, p, fld[idx], v); \
+} while (0)
+
 #define MLX5_GET64(typ, p, fld) be64_to_cpu(*((__be64 *)(p) + __mlx5_64_off(typ, fld)))
 
 #define MLX5_GET64_PR(typ, p, fld) ({ \