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Message-Id: <20250917-can-raw-repack-v2-2-395e8b3a4437@kernel.org>
Date: Wed, 17 Sep 2025 13:48:25 +0900
From: Vincent Mailhol <mailhol@...nel.org>
To: Oliver Hartkopp <socketcan@...tkopp.net>,
Marc Kleine-Budde <mkl@...gutronix.de>
Cc: linux-can@...r.kernel.org, linux-kernel@...r.kernel.org,
Christophe Jaillet <christophe.jaillet@...adoo.fr>,
Vincent Mailhol <mailhol@...nel.org>
Subject: [PATCH v2 2/3] can: raw: use bitfields to store flags in struct
raw_sock
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 <socketcan@...tkopp.net>
Signed-off-by: Vincent Mailhol <mailhol@...nel.org>
---
Changelog:
v1 -> v2:
- also add raw_sock->bound and raw_sock->join_filters to the
bitfield
---
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 db21d8a8c54d1b6a25a72c7a9d11d5c94f3187b5..5a5ded519cd1768456c234c42dc4e865f7350dab 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:
--
2.49.1
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