Commit b8a4ddb2 authored Oct 12, 2016 by Tom Herbert Committed by David S. Miller Oct 13, 2016

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: a533ed5e ("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>

parent 9a765881

drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -287,7 +287,7 @@ retry:

		goto retry;
		}
		MLX5_SET64(manage_pages_in, in, pas[i], addr);
		MLX5_ARRAY_SET64(manage_pages_in, in, pas, i, addr);
		}

		MLX5_SET(manage_pages_in, in, opcode, MLX5_CMD_OP_MANAGE_PAGES);
		@@ -344,7 +344,7 @@ static int reclaim_pages_cmd(struct mlx5_core_dev *dev,
		if (fwp->func_id != func_id)
		continue;

		MLX5_SET64(manage_pages_out, out, pas[i], fwp->addr);
		MLX5_ARRAY_SET64(manage_pages_out, out, pas, i, fwp->addr);
		i++;
		}

include/linux/mlx5/device.h

+11 −2

Original line number	Diff line number	Diff line
		@@ -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) ({ \

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