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 <jk@codeconstruct.com.au>. Contains a fix that was: Reported-by: kernel test robot <lkp@intel.com>
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| @@ -44,7 +44,25 @@ struct sockaddr_mctp_ext { · 43 unmodified lines | ||
| 44 | 44 | |
| 45 | 45 | #define MCTP_TAG_MASK 0x07 |
| 46 | 46 | #define MCTP_TAG_OWNER 0x08 |
| 47 | +#define MCTP_TAG_PREALLOC 0x10 | |
| 47 | 48 | |
| 48 | 49 | #define MCTP_OPT_ADDR_EXT 1 |
| 49 | 50 | |
| 51 | +#define SIOCMCTPALLOCTAG (SIOCPROTOPRIVATE + 0) | |
| 52 | +#define SIOCMCTPDROPTAG (SIOCPROTOPRIVATE + 1) | |
| 53 | + | |
| 54 | +struct mctp_ioc_tag_ctl { | |
| 55 | + mctp_eid_t peer_addr; | |
| 56 | + | |
| 57 | + /* For SIOCMCTPALLOCTAG: must be passed as zero, kernel will | |
| 58 | + * populate with the allocated tag value. Returned tag value will | |
| 59 | + * always have TO and PREALLOC set. | |
| 60 | + * | |
| 61 | + * For SIOCMCTPDROPTAG: userspace provides tag value to drop, from | |
| 62 | + * a prior SIOCMCTPALLOCTAG call (and so must have TO and PREALLOC set). | |
| 63 | + */ | |
| 64 | + __u8 tag; | |
| 65 | + __u16 flags; | |
| 66 | +}; | |
| 67 | + | |
| 50 | 68 | #endif /* __UAPI_MCTP_H */ |