svn commit: r283168 - head/usr.sbin/bhyve

[Peter Grehan]

Author: grehan
Date: Thu May 21 04:19:22 2015
New Revision: 283168
URL: https://svnweb.freebsd.org/changeset/base/283168

Log:
  Temporarily revert r282922 which bumped the max descriptors.
  
  While there is no issued with the number of descriptors in
  a virtio indirect descriptor, it's a guest's choice as to
  whether indirect descriptors are used. For the case where
  they aren't, the virtio block ring size is still 64 which
  is less than the now reported max_segs of 67. This results
  in an assertion in recent Linux guests even though it was
  benign since they were using indirect descs.
  
  The intertwined relationship between virtio ring size,
  max seg size and blockif queue size will be addressed
  in an upcoming commit, at which point the max descriptors
  will again be bumped up to 67.

Modified:
  head/usr.sbin/bhyve/block_if.h

Modified: head/usr.sbin/bhyve/block_if.h
==============================================================================
--- head/usr.sbin/bhyve/block_if.h	Thu May 21 03:32:44 2015	(r283167)
+++ head/usr.sbin/bhyve/block_if.h	Thu May 21 04:19:22 2015	(r283168)
@@ -39,7 +39,7 @@
 #include <sys/uio.h>
 #include <sys/unistd.h>
 
-#define BLOCKIF_IOV_MAX		67	/* not practical to be IOV_MAX */
+#define BLOCKIF_IOV_MAX		33	/* not practical to be IOV_MAX */
 
 struct blockif_req {
 	struct iovec	br_iov[BLOCKIF_IOV_MAX];