From 63ed1aab3d40aa61aaa66819bdce9377ac7f40fa Mon Sep 17 00:00:00 2001 From: Matt Johnston Date: Wed, 9 Feb 2022 12:05:57 +0800 Subject: mctp: Add SIOCMCTP{ALLOC,DROP}TAG ioctls for tag control This change adds a couple of new ioctls for mctp sockets: SIOCMCTPALLOCTAG and SIOCMCTPDROPTAG. These ioctls provide facilities for explicit allocation / release of tags, overriding the automatic allocate-on-send/release-on-reply and timeout behaviours. This allows userspace more control over messages that may not fit a simple request/response model. In order to indicate a pre-allocated tag to the sendmsg() syscall, we introduce a new flag to the struct sockaddr_mctp.smctp_tag value: MCTP_TAG_PREALLOC. Additional changes from Jeremy Kerr . Contains a fix that was: Reported-by: kernel test robot Signed-off-by: Matt Johnston Signed-off-by: Jeremy Kerr Signed-off-by: David S. Miller --- include/uapi/linux/mctp.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/mctp.h b/include/uapi/linux/mctp.h index 07b0318716fc..154ab56651f1 100644 --- a/include/uapi/linux/mctp.h +++ b/include/uapi/linux/mctp.h @@ -44,7 +44,25 @@ struct sockaddr_mctp_ext { #define MCTP_TAG_MASK 0x07 #define MCTP_TAG_OWNER 0x08 +#define MCTP_TAG_PREALLOC 0x10 #define MCTP_OPT_ADDR_EXT 1 +#define SIOCMCTPALLOCTAG (SIOCPROTOPRIVATE + 0) +#define SIOCMCTPDROPTAG (SIOCPROTOPRIVATE + 1) + +struct mctp_ioc_tag_ctl { + mctp_eid_t peer_addr; + + /* For SIOCMCTPALLOCTAG: must be passed as zero, kernel will + * populate with the allocated tag value. Returned tag value will + * always have TO and PREALLOC set. + * + * For SIOCMCTPDROPTAG: userspace provides tag value to drop, from + * a prior SIOCMCTPALLOCTAG call (and so must have TO and PREALLOC set). + */ + __u8 tag; + __u16 flags; +}; + #endif /* __UAPI_MCTP_H */ -- cgit v1.2.3