Assert socket buffer lock in sb_lock() to protect socket buffer sleep

lock state.  Convert tsleep() into msleep() with socket buffer mutex
as argument.  Hold socket buffer lock over sbunlock() to protect sleep
lock state.

Assert socket buffer lock in sbwait() to protect the socket buffer
wait state.  Convert tsleep() into msleep() with socket buffer mutex
as argument.

Modify sofree(), sosend(), and soreceive() to acquire SOCKBUF_LOCK()
in order to call into these functions with the lock, as well as to
start protecting other socket buffer use in their implementation.  Drop
the socket buffer mutexes around calls into the protocol layer, around
potentially blocking operations, for copying to/from user space, and
VM operations relating to zero-copy.  Assert the socket buffer mutex
strategically after code sections or at the beginning of loops.  In
some cases, modify return code to ensure locks are properly dropped.

Convert the potentially blocking allocation of storage for the remote
address in soreceive() into a non-blocking allocation; we may wish to
move the allocation earlier so that it can block prior to acquisition
of the socket buffer lock.

Drop some spl use.

NOTE: Some races exist in the current structuring of sosend() and
soreceive().  This commit only merges basic socket locking in this
code; follow-up commits will close additional races.  As merged,
these changes are not sufficient to run without Giant safely.

Reviewed by:	juli, tjr

1 files changed, 6 insertions, 2 deletions

diff --git a/sys/kern/uipc_sockbuf.c b/sys/kern/uipc_sockbuf.c
index c385253..0e4e99b 100644
--- a/sys/kern/uipc_sockbuf.c
+++ b/sys/kern/uipc_sockbuf.c
@@ -323,8 +323,10 @@ sbwait(sb)
 	struct sockbuf *sb;
 {
 
+	SOCKBUF_LOCK_ASSERT(sb);
+
 	sb->sb_flags |= SB_WAIT;
-	return (tsleep(&sb->sb_cc,
+	return (msleep(&sb->sb_cc, &sb->sb_mtx,
 	    (sb->sb_flags & SB_NOINTR) ? PSOCK : PSOCK | PCATCH, "sbwait",
 	    sb->sb_timeo));
 }
@@ -339,9 +341,11 @@ sb_lock(sb)
 {
 	int error;
 
+	SOCKBUF_LOCK_ASSERT(sb);
+
 	while (sb->sb_flags & SB_LOCK) {
 		sb->sb_flags |= SB_WANT;
-		error = tsleep(&sb->sb_flags,
+		error = msleep(&sb->sb_flags, &sb->sb_mtx,
 		    (sb->sb_flags & SB_NOINTR) ? PSOCK : PSOCK|PCATCH,
 		    "sblock", 0);
 		if (error)