Merge branch 'MCTP-tag-control-interface'

Jeremy Kerr says:

====================
MCTP tag control interface

This series implements a small interface for userspace-controlled
message tag allocation for the MCTP protocol. Rather than leaving the
kernel to allocate per-message tag values, userspace can explicitly
allocate (and release) message tags through two new ioctls:
SIOCMCTPALLOCTAG and SIOCMCTPDROPTAG.

In order to do this, we first introduce some minor changes to the tag
handling, including a couple of new tests for the route input paths.

As always, any comments/queries/etc are most welcome.

v2:
 - make mctp_lookup_prealloc_tag static
 - minor checkpatch formatting fixes
====================

Signed-off-by: David S. Miller <[email protected]>

1 files changed, 18 insertions, 0 deletions

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 */