svn commit: r343627 - in head/sys: kern sys

[Gleb Smirnoff]

Author: glebius
Date: Thu Jan 31 22:37:28 2019
New Revision: 343627
URL: https://svnweb.freebsd.org/changeset/base/343627

Log:
  Add new m_ext type for data for M_NOFREE mbufs, which doesn't actually do
  anything except several assertions.  This type is going to be used for
  temporary on stack mbufs, that point into data in receive ring of a NIC,
  that shall not be freed.  Such mbuf can not be stored or reallocated, its
  life time is current context.

Modified:
  head/sys/kern/kern_mbuf.c
  head/sys/sys/mbuf.h

Modified: head/sys/kern/kern_mbuf.c
==============================================================================
--- head/sys/kern/kern_mbuf.c	Thu Jan 31 22:27:39 2019	(r343626)
+++ head/sys/kern/kern_mbuf.c	Thu Jan 31 22:37:28 2019	(r343627)
@@ -847,7 +847,8 @@ mb_free_ext(struct mbuf *m)
 	 */
 	if (m->m_flags & M_NOFREE) {
 		freembuf = 0;
-		KASSERT(m->m_ext.ext_type == EXT_EXTREF,
+		KASSERT(m->m_ext.ext_type == EXT_EXTREF ||
+		    m->m_ext.ext_type == EXT_RXRING,
 		    ("%s: no-free mbuf %p has wrong type", __func__, m));
 	} else
 		freembuf = 1;
@@ -890,6 +891,10 @@ mb_free_ext(struct mbuf *m)
 			KASSERT(m->m_ext.ext_free != NULL,
 			    ("%s: ext_free not set", __func__));
 			m->m_ext.ext_free(m);
+			break;
+		case EXT_RXRING:
+			KASSERT(m->m_ext.ext_free == NULL,
+			    ("%s: ext_free is set", __func__));
 			break;
 		default:
 			KASSERT(m->m_ext.ext_type == 0,

Modified: head/sys/sys/mbuf.h
==============================================================================
--- head/sys/sys/mbuf.h	Thu Jan 31 22:27:39 2019	(r343626)
+++ head/sys/sys/mbuf.h	Thu Jan 31 22:37:28 2019	(r343627)
@@ -443,6 +443,7 @@ struct mbuf {
 #define	EXT_JUMBO16	5	/* jumbo cluster 16184 bytes */
 #define	EXT_PACKET	6	/* mbuf+cluster from packet zone */
 #define	EXT_MBUF	7	/* external mbuf reference */
+#define	EXT_RXRING	8	/* data in NIC receive ring */
 
 #define	EXT_VENDOR1	224	/* for vendor-internal use */
 #define	EXT_VENDOR2	225	/* for vendor-internal use */