Re: [PATCH] vdpa/mlx5: Avoid warnings about shifts on 32-bit platforms
From: Randy Dunlap
Date: Fri Aug 21 2020 - 19:13:32 EST
On 8/21/20 3:50 PM, Nathan Chancellor wrote:
> Clang warns several times when building for 32-bit ARM along the lines
> of:
>
> drivers/vdpa/mlx5/net/mlx5_vnet.c:1462:31: warning: shift count >= width
> of type [-Wshift-count-overflow]
> ndev->mvdev.mlx_features |= BIT(VIRTIO_F_VERSION_1);
> ^~~~~~~~~~~~~~~~~~~~~~~
>
> This is related to the BIT macro, which uses an unsigned long literal,
> which is 32-bit on ARM so having a shift equal to or larger than 32 will
> cause this warning, such as the above, where VIRTIO_F_VERSION_1 is 32.
> To avoid this, use BIT_ULL, which will be an unsigned long long. This
> matches the size of the features field throughout this driver, which is
> u64 so there should be no functional change.
>
> Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5 devices")
> Link: https://github.com/ClangBuiltLinux/linux/issues/1140
> Signed-off-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
on 2020-AUG-10 for i386:
https://lore.kernel.org/linux-next/5a7a0e6d-842a-78f6-aeac-c5b4c27b7186@xxxxxxxxxxxxx/
:(
Acked-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> # build-tested
Thanks.
> ---
> drivers/vdpa/mlx5/net/mlx5_vnet.c | 50 +++++++++++++++----------------
> 1 file changed, 25 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 9df69d5efe8c..70676a6d1691 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -16,19 +16,19 @@
> #define to_mvdev(__vdev) container_of((__vdev), struct mlx5_vdpa_dev, vdev)
>
> #define VALID_FEATURES_MASK \
> - (BIT(VIRTIO_NET_F_CSUM) | BIT(VIRTIO_NET_F_GUEST_CSUM) | \
> - BIT(VIRTIO_NET_F_CTRL_GUEST_OFFLOADS) | BIT(VIRTIO_NET_F_MTU) | BIT(VIRTIO_NET_F_MAC) | \
> - BIT(VIRTIO_NET_F_GUEST_TSO4) | BIT(VIRTIO_NET_F_GUEST_TSO6) | \
> - BIT(VIRTIO_NET_F_GUEST_ECN) | BIT(VIRTIO_NET_F_GUEST_UFO) | BIT(VIRTIO_NET_F_HOST_TSO4) | \
> - BIT(VIRTIO_NET_F_HOST_TSO6) | BIT(VIRTIO_NET_F_HOST_ECN) | BIT(VIRTIO_NET_F_HOST_UFO) | \
> - BIT(VIRTIO_NET_F_MRG_RXBUF) | BIT(VIRTIO_NET_F_STATUS) | BIT(VIRTIO_NET_F_CTRL_VQ) | \
> - BIT(VIRTIO_NET_F_CTRL_RX) | BIT(VIRTIO_NET_F_CTRL_VLAN) | \
> - BIT(VIRTIO_NET_F_CTRL_RX_EXTRA) | BIT(VIRTIO_NET_F_GUEST_ANNOUNCE) | \
> - BIT(VIRTIO_NET_F_MQ) | BIT(VIRTIO_NET_F_CTRL_MAC_ADDR) | BIT(VIRTIO_NET_F_HASH_REPORT) | \
> - BIT(VIRTIO_NET_F_RSS) | BIT(VIRTIO_NET_F_RSC_EXT) | BIT(VIRTIO_NET_F_STANDBY) | \
> - BIT(VIRTIO_NET_F_SPEED_DUPLEX) | BIT(VIRTIO_F_NOTIFY_ON_EMPTY) | \
> - BIT(VIRTIO_F_ANY_LAYOUT) | BIT(VIRTIO_F_VERSION_1) | BIT(VIRTIO_F_ACCESS_PLATFORM) | \
> - BIT(VIRTIO_F_RING_PACKED) | BIT(VIRTIO_F_ORDER_PLATFORM) | BIT(VIRTIO_F_SR_IOV))
> + (BIT_ULL(VIRTIO_NET_F_CSUM) | BIT_ULL(VIRTIO_NET_F_GUEST_CSUM) | \
> + BIT_ULL(VIRTIO_NET_F_CTRL_GUEST_OFFLOADS) | BIT_ULL(VIRTIO_NET_F_MTU) | BIT_ULL(VIRTIO_NET_F_MAC) | \
> + BIT_ULL(VIRTIO_NET_F_GUEST_TSO4) | BIT_ULL(VIRTIO_NET_F_GUEST_TSO6) | \
> + BIT_ULL(VIRTIO_NET_F_GUEST_ECN) | BIT_ULL(VIRTIO_NET_F_GUEST_UFO) | BIT_ULL(VIRTIO_NET_F_HOST_TSO4) | \
> + BIT_ULL(VIRTIO_NET_F_HOST_TSO6) | BIT_ULL(VIRTIO_NET_F_HOST_ECN) | BIT_ULL(VIRTIO_NET_F_HOST_UFO) | \
> + BIT_ULL(VIRTIO_NET_F_MRG_RXBUF) | BIT_ULL(VIRTIO_NET_F_STATUS) | BIT_ULL(VIRTIO_NET_F_CTRL_VQ) | \
> + BIT_ULL(VIRTIO_NET_F_CTRL_RX) | BIT_ULL(VIRTIO_NET_F_CTRL_VLAN) | \
> + BIT_ULL(VIRTIO_NET_F_CTRL_RX_EXTRA) | BIT_ULL(VIRTIO_NET_F_GUEST_ANNOUNCE) | \
> + BIT_ULL(VIRTIO_NET_F_MQ) | BIT_ULL(VIRTIO_NET_F_CTRL_MAC_ADDR) | BIT_ULL(VIRTIO_NET_F_HASH_REPORT) | \
> + BIT_ULL(VIRTIO_NET_F_RSS) | BIT_ULL(VIRTIO_NET_F_RSC_EXT) | BIT_ULL(VIRTIO_NET_F_STANDBY) | \
> + BIT_ULL(VIRTIO_NET_F_SPEED_DUPLEX) | BIT_ULL(VIRTIO_F_NOTIFY_ON_EMPTY) | \
> + BIT_ULL(VIRTIO_F_ANY_LAYOUT) | BIT_ULL(VIRTIO_F_VERSION_1) | BIT_ULL(VIRTIO_F_ACCESS_PLATFORM) | \
> + BIT_ULL(VIRTIO_F_RING_PACKED) | BIT_ULL(VIRTIO_F_ORDER_PLATFORM) | BIT_ULL(VIRTIO_F_SR_IOV))
>
> #define VALID_STATUS_MASK \
> (VIRTIO_CONFIG_S_ACKNOWLEDGE | VIRTIO_CONFIG_S_DRIVER | VIRTIO_CONFIG_S_DRIVER_OK | \
> @@ -149,7 +149,7 @@ static bool mlx5_vdpa_debug;
>
> #define MLX5_LOG_VIO_FLAG(_feature) \
> do { \
> - if (features & BIT(_feature)) \
> + if (features & BIT_ULL(_feature)) \
> mlx5_vdpa_info(mvdev, "%s\n", #_feature); \
> } while (0)
>
> @@ -750,10 +750,10 @@ static bool vq_is_tx(u16 idx)
>
> static u16 get_features_12_3(u64 features)
> {
> - return (!!(features & BIT(VIRTIO_NET_F_HOST_TSO4)) << 9) |
> - (!!(features & BIT(VIRTIO_NET_F_HOST_TSO6)) << 8) |
> - (!!(features & BIT(VIRTIO_NET_F_CSUM)) << 7) |
> - (!!(features & BIT(VIRTIO_NET_F_GUEST_CSUM)) << 6);
> + return (!!(features & BIT_ULL(VIRTIO_NET_F_HOST_TSO4)) << 9) |
> + (!!(features & BIT_ULL(VIRTIO_NET_F_HOST_TSO6)) << 8) |
> + (!!(features & BIT_ULL(VIRTIO_NET_F_CSUM)) << 7) |
> + (!!(features & BIT_ULL(VIRTIO_NET_F_GUEST_CSUM)) << 6);
> }
>
> static int create_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)
> @@ -1439,13 +1439,13 @@ static u64 mlx_to_vritio_features(u16 dev_features)
> u64 result = 0;
>
> if (dev_features & MLX5_VIRTIO_NET_F_GUEST_CSUM)
> - result |= BIT(VIRTIO_NET_F_GUEST_CSUM);
> + result |= BIT_ULL(VIRTIO_NET_F_GUEST_CSUM);
> if (dev_features & MLX5_VIRTIO_NET_F_CSUM)
> - result |= BIT(VIRTIO_NET_F_CSUM);
> + result |= BIT_ULL(VIRTIO_NET_F_CSUM);
> if (dev_features & MLX5_VIRTIO_NET_F_HOST_TSO6)
> - result |= BIT(VIRTIO_NET_F_HOST_TSO6);
> + result |= BIT_ULL(VIRTIO_NET_F_HOST_TSO6);
> if (dev_features & MLX5_VIRTIO_NET_F_HOST_TSO4)
> - result |= BIT(VIRTIO_NET_F_HOST_TSO4);
> + result |= BIT_ULL(VIRTIO_NET_F_HOST_TSO4);
>
> return result;
> }
> @@ -1459,15 +1459,15 @@ static u64 mlx5_vdpa_get_features(struct vdpa_device *vdev)
> dev_features = MLX5_CAP_DEV_VDPA_EMULATION(mvdev->mdev, device_features_bits_mask);
> ndev->mvdev.mlx_features = mlx_to_vritio_features(dev_features);
> if (MLX5_CAP_DEV_VDPA_EMULATION(mvdev->mdev, virtio_version_1_0))
> - ndev->mvdev.mlx_features |= BIT(VIRTIO_F_VERSION_1);
> - ndev->mvdev.mlx_features |= BIT(VIRTIO_F_ACCESS_PLATFORM);
> + ndev->mvdev.mlx_features |= BIT_ULL(VIRTIO_F_VERSION_1);
> + ndev->mvdev.mlx_features |= BIT_ULL(VIRTIO_F_ACCESS_PLATFORM);
> print_features(mvdev, ndev->mvdev.mlx_features, false);
> return ndev->mvdev.mlx_features;
> }
>
> static int verify_min_features(struct mlx5_vdpa_dev *mvdev, u64 features)
> {
> - if (!(features & BIT(VIRTIO_F_ACCESS_PLATFORM)))
> + if (!(features & BIT_ULL(VIRTIO_F_ACCESS_PLATFORM)))
> return -EOPNOTSUPP;
>
> return 0;
>
> base-commit: 8a7c3213db068135e816a6a517157de6443290d6
>
--
~Randy