From: Vincent Mailhol The bound, loopback, recv_own_msgs, fd_frames, xl_frames and join_filters fields of struct raw_sock just need to store one bit of information. Declare all those members as a bitfields of type unsigned int and width one bit. Add a temporary variable to raw_setsockopt() and raw_getsockopt() to make the conversion between the stored bits and the socket interface. This reduces the size of struct raw_sock by sixteen bytes. Statistics before: $ pahole --class_name=raw_sock net/can/raw.o struct raw_sock { struct sock sk __attribute__((__aligned__(8))); /* 0 776 */ /* XXX last struct has 1 bit hole */ /* --- cacheline 12 boundary (768 bytes) was 8 bytes ago --- */ int bound; /* 776 4 */ int ifindex; /* 780 4 */ struct net_device * dev; /* 784 8 */ netdevice_tracker dev_tracker; /* 792 0 */ struct list_head notifier; /* 792 16 */ int loopback; /* 808 4 */ int recv_own_msgs; /* 812 4 */ int fd_frames; /* 816 4 */ int xl_frames; /* 820 4 */ struct can_raw_vcid_options raw_vcid_opts; /* 824 4 */ canid_t tx_vcid_shifted; /* 828 4 */ /* --- cacheline 13 boundary (832 bytes) --- */ canid_t rx_vcid_shifted; /* 832 4 */ canid_t rx_vcid_mask_shifted; /* 836 4 */ int join_filters; /* 840 4 */ int count; /* 844 4 */ struct can_filter dfilter; /* 848 8 */ struct can_filter * filter; /* 856 8 */ can_err_mask_t err_mask; /* 864 4 */ /* XXX 4 bytes hole, try to pack */ struct uniqframe * uniq; /* 872 8 */ /* size: 880, cachelines: 14, members: 20 */ /* sum members: 876, holes: 1, sum holes: 4 */ /* member types with bit holes: 1, total: 1 */ /* forced alignments: 1 */ /* last cacheline: 48 bytes */ } __attribute__((__aligned__(8))); ...and after: $ pahole --class_name=raw_sock net/can/raw.o struct raw_sock { struct sock sk __attribute__((__aligned__(8))); /* 0 776 */ /* XXX last struct has 1 bit hole */ /* --- cacheline 12 boundary (768 bytes) was 8 bytes ago --- */ int ifindex; /* 776 4 */ /* XXX 4 bytes hole, try to pack */ struct net_device * dev; /* 784 8 */ netdevice_tracker dev_tracker; /* 792 0 */ struct list_head notifier; /* 792 16 */ unsigned int bound:1; /* 808: 0 4 */ unsigned int loopback:1; /* 808: 1 4 */ unsigned int recv_own_msgs:1; /* 808: 2 4 */ unsigned int fd_frames:1; /* 808: 3 4 */ unsigned int xl_frames:1; /* 808: 4 4 */ unsigned int join_filters:1; /* 808: 5 4 */ /* XXX 2 bits hole, try to pack */ /* Bitfield combined with next fields */ struct can_raw_vcid_options raw_vcid_opts; /* 809 4 */ /* XXX 3 bytes hole, try to pack */ canid_t tx_vcid_shifted; /* 816 4 */ canid_t rx_vcid_shifted; /* 820 4 */ canid_t rx_vcid_mask_shifted; /* 824 4 */ int count; /* 828 4 */ /* --- cacheline 13 boundary (832 bytes) --- */ struct can_filter dfilter; /* 832 8 */ struct can_filter * filter; /* 840 8 */ can_err_mask_t err_mask; /* 848 4 */ /* XXX 4 bytes hole, try to pack */ struct uniqframe * uniq; /* 856 8 */ /* size: 864, cachelines: 14, members: 20 */ /* sum members: 852, holes: 3, sum holes: 11 */ /* sum bitfield members: 6 bits, bit holes: 1, sum bit holes: 2 bits */ /* member types with bit holes: 1, total: 1 */ /* forced alignments: 1 */ /* last cacheline: 32 bytes */ } __attribute__((__aligned__(8))); Acked-by: Oliver Hartkopp Signed-off-by: Vincent Mailhol Link: https://patch.msgid.link/20250917-can-raw-repack-v2-2-395e8b3a4437@kernel.org Signed-off-by: Marc Kleine-Budde --- net/can/raw.c | 59 ++++++++++++++++++++++++++++++--------------------- 1 file changed, 35 insertions(+), 24 deletions(-) diff --git a/net/can/raw.c b/net/can/raw.c index db21d8a8c54d..5a5ded519cd1 100644 --- a/net/can/raw.c +++ b/net/can/raw.c @@ -82,20 +82,20 @@ struct uniqframe { struct raw_sock { struct sock sk; - int bound; int ifindex; struct net_device *dev; netdevice_tracker dev_tracker; struct list_head notifier; - int loopback; - int recv_own_msgs; - int fd_frames; - int xl_frames; + unsigned int bound:1; + unsigned int loopback:1; + unsigned int recv_own_msgs:1; + unsigned int fd_frames:1; + unsigned int xl_frames:1; + unsigned int join_filters:1; struct can_raw_vcid_options raw_vcid_opts; canid_t tx_vcid_shifted; canid_t rx_vcid_shifted; canid_t rx_vcid_mask_shifted; - int join_filters; int count; /* number of active filters */ struct can_filter dfilter; /* default/single filter */ struct can_filter *filter; /* pointer to filter(s) */ @@ -560,8 +560,8 @@ static int raw_setsockopt(struct socket *sock, int level, int optname, struct can_filter sfilter; /* single filter */ struct net_device *dev = NULL; can_err_mask_t err_mask = 0; - int fd_frames; int count = 0; + int flag; int err = 0; if (level != SOL_CAN_RAW) @@ -682,44 +682,48 @@ static int raw_setsockopt(struct socket *sock, int level, int optname, break; case CAN_RAW_LOOPBACK: - if (optlen != sizeof(ro->loopback)) + if (optlen != sizeof(flag)) return -EINVAL; - if (copy_from_sockptr(&ro->loopback, optval, optlen)) + if (copy_from_sockptr(&flag, optval, optlen)) return -EFAULT; + ro->loopback = !!flag; break; case CAN_RAW_RECV_OWN_MSGS: - if (optlen != sizeof(ro->recv_own_msgs)) + if (optlen != sizeof(flag)) return -EINVAL; - if (copy_from_sockptr(&ro->recv_own_msgs, optval, optlen)) + if (copy_from_sockptr(&flag, optval, optlen)) return -EFAULT; + ro->recv_own_msgs = !!flag; break; case CAN_RAW_FD_FRAMES: - if (optlen != sizeof(fd_frames)) + if (optlen != sizeof(flag)) return -EINVAL; - if (copy_from_sockptr(&fd_frames, optval, optlen)) + if (copy_from_sockptr(&flag, optval, optlen)) return -EFAULT; /* Enabling CAN XL includes CAN FD */ - if (ro->xl_frames && !fd_frames) + if (ro->xl_frames && !flag) return -EINVAL; - ro->fd_frames = fd_frames; + ro->fd_frames = !!flag; break; case CAN_RAW_XL_FRAMES: - if (optlen != sizeof(ro->xl_frames)) + if (optlen != sizeof(flag)) return -EINVAL; - if (copy_from_sockptr(&ro->xl_frames, optval, optlen)) + if (copy_from_sockptr(&flag, optval, optlen)) return -EFAULT; + ro->xl_frames = !!flag; + /* Enabling CAN XL includes CAN FD */ if (ro->xl_frames) ro->fd_frames = ro->xl_frames; @@ -739,12 +743,13 @@ static int raw_setsockopt(struct socket *sock, int level, int optname, break; case CAN_RAW_JOIN_FILTERS: - if (optlen != sizeof(ro->join_filters)) + if (optlen != sizeof(flag)) return -EINVAL; - if (copy_from_sockptr(&ro->join_filters, optval, optlen)) + if (copy_from_sockptr(&flag, optval, optlen)) return -EFAULT; + ro->join_filters = !!flag; break; default: @@ -758,6 +763,7 @@ static int raw_getsockopt(struct socket *sock, int level, int optname, { struct sock *sk = sock->sk; struct raw_sock *ro = raw_sk(sk); + int flag; int len; void *val; @@ -806,25 +812,29 @@ static int raw_getsockopt(struct socket *sock, int level, int optname, case CAN_RAW_LOOPBACK: if (len > sizeof(int)) len = sizeof(int); - val = &ro->loopback; + flag = ro->loopback; + val = &flag; break; case CAN_RAW_RECV_OWN_MSGS: if (len > sizeof(int)) len = sizeof(int); - val = &ro->recv_own_msgs; + flag = ro->recv_own_msgs; + val = &flag; break; case CAN_RAW_FD_FRAMES: if (len > sizeof(int)) len = sizeof(int); - val = &ro->fd_frames; + flag = ro->fd_frames; + val = &flag; break; case CAN_RAW_XL_FRAMES: if (len > sizeof(int)) len = sizeof(int); - val = &ro->xl_frames; + flag = ro->xl_frames; + val = &flag; break; case CAN_RAW_XL_VCID_OPTS: { @@ -849,7 +859,8 @@ static int raw_getsockopt(struct socket *sock, int level, int optname, case CAN_RAW_JOIN_FILTERS: if (len > sizeof(int)) len = sizeof(int); - val = &ro->join_filters; + flag = ro->join_filters; + val = &flag; break; default: -- 2.51.0