Hi Gleb:

Randall had mentioned these in-flight changes to me, and I can see how these might substantially reduce latency in usefully filling the TCP pipe when the window is opening rapidly (among other things). As with others, I'm a bit cautious about further increases in asynchrony within mbufs -- but think that the design choice to limit asynchronous access to mbuf data, rather than metadata, is a sensible one. I am especially pleased that the near-invariant that access to mbuf fields of mbufs owned by the socket buffer occurs only with the socket-buffer mutex held (note that there are one or two known nasty exceptions to this rule -- e.g., in MSG_PEEK that it is worth being aware of). I tend to agree with the view that socket upcalls are not the right mechanism to use here, as those both serve another function, and can run into locking difficulties due to their calling contexts (I am aware of some potential outstanding issues here for existing upcall consumers, in fact).

I do have a substantial worry about 'compatibility' -- which is to say, the risk of not only running into trouble with more obscure bits of the network stack, but also third-party extensions in local code bases that may make previously reasonable assumptions about mbuf behaviour. One way to bound the scope of that issue is to ensure, very firmly, that these flags can never leak out of the socket-buffer/protocol components that explicitly support it. I think I might feel more comfortable if these were globally visible mbuf flags, which we could assert never passed through certain types of interfaces -- e.g., made it to ip_output(); it might also be useful to assert that these flags are never set when an mbuf is freed back to the mbuf allocator. I also worry that leakage of M_PROTO flags from other components could lead to quite hard-to-debug problems, and so it would be good to ensure that subsystems that will use these flags assert that they are never set as they arrive in the subsystem (e.g., tcp_input()). I'm not sure how we're doing on mbuf flags, but we might soon find we require another field in struct mbuf for them. Anywhere we can use assertions to help us with this kind of problem, I think it's a big win.

Although these changes have clearly been refined over an extended period, and were developed in a Subversion project branch, I think it would have been nice to be able to have more "Reviewed by:" entries in the commit message. I've been really happy to see a gradual change over the last few years towards a large percentage of network-stack commits having that tag, and think it's worth pursuing this pretty vigorously. A phabricator round to networks@ (or whatever the recently created alias/group was) would not go amiss in the future. While everyone is busy, creating an environment of mutual review (I'll scratch your back if you scratch mine) is very valuable -- especially for subsystems as subtle as the network stack. Looking back in the e-mail archives, I see that you did post a phabricator link to an earlier version of this work in May -- I suspect more armtwisting was required, but would in general be worth it. (I've been very tuned out the last few months due to ongoing things outside of the FreeBSD world -- but please do feel free to ping me if there's a critical patch like this in flight where I can at least lend a hand with a quick read.)

Although not an immediate issue, it may be worth looking at what happens to performance with these changes in the presence of lower-latency storage devices, such as nvme. Where there is substantial latency due to a spinning disk, or even a congested SATA-attached SSD, it's easy to see how these changes would improve performance. I do worry that with lower latency, you might see increases in lock contention -- or at least shifts, which would be worth understanding. I'm not sure if your testing environment is suitable for that (nor, I think, the FreeBSD Project's netperf cluster -- we've just received our first nvme device at the Computer Laboratory for network-stack performance work .. and it will be interesting to see how that plays out. With <30us RTT on I/O, multiqueue support, etc, the dynamics are changing quite a lot.) The concern would be that we might now be doing many more socket-buffer locking/wakeup-style events than before, and that if they are paced too quickly the threads will bump into each other.

FWIW, I think it would be worth pondering adding an aio_sendfile(), if only because it would make it easier to expose this kernel asynchrony to userspace concurrency frameworks like libdispatch.

Robert

On Sun, 30 Nov 2014, Gleb Smirnoff wrote:

Author: glebius
Date: Sun Nov 30 12:52:33 2014
New Revision: 275326
URL: https://svnweb.freebsd.org/changeset/base/275326

Log:
 Merge from projects/sendfile:

 o Introduce a notion of "not ready" mbufs in socket buffers.  These
 mbufs are now being populated by some I/O in background and are
 referenced outside.  This forces following implications:
 - An mbuf which is "not ready" can't be taken out of the buffer.
 - An mbuf that is behind a "not ready" in the queue neither.
 - If sockbet buffer is flushed, then "not ready" mbufs shouln't be
   freed.

 o In struct sockbuf the sb_cc field is split into sb_ccc and sb_acc.
   The sb_ccc stands for ""claimed character count", or "committed
   character count".  And the sb_acc is "available character count".
   Consumers of socket buffer API shouldn't already access them directly,
   but use sbused() and sbavail() respectively.
 o Not ready mbufs are marked with M_NOTREADY, and ready but blocked ones
   with M_BLOCKED.
 o New field sb_fnrdy points to the first not ready mbuf, to avoid linear
   search.
 o New function sbready() is provided to activate certain amount of mbufs
   in a socket buffer.

 A special note on SCTP:
   SCTP has its own sockbufs.  Unfortunately, FreeBSD stack doesn't yet
 allow protocol specific sockbufs.  Thus, SCTP does some hacks to make
 itself compatible with FreeBSD: it manages sockbufs on its own, but keeps
 sb_cc updated to inform the stack of amount of data in them.  The new
 notion of "not ready" data isn't supported by SCTP.  Instead, only a
 mechanical substitute is done: s/sb_cc/sb_ccc/.
   A proper solution would be to take away struct sockbuf from struct
 socket and allow protocols to implement their own socket buffers, like
 SCTP already does.  This was discussed with rrs@.

 Sponsored by:  Netflix
 Sponsored by:  Nginx, Inc.

Modified:
 head/sys/dev/cxgbe/tom/t4_ddp.c
 head/sys/kern/uipc_debug.c
 head/sys/kern/uipc_sockbuf.c
 head/sys/kern/uipc_socket.c
 head/sys/netinet/sctp_indata.c
 head/sys/netinet/sctp_input.c
 head/sys/netinet/sctp_os_bsd.h
 head/sys/netinet/sctp_output.c
 head/sys/netinet/sctp_pcb.c
 head/sys/netinet/sctp_pcb.h
 head/sys/netinet/sctp_structs.h
 head/sys/netinet/sctp_usrreq.c
 head/sys/netinet/sctp_var.h
 head/sys/netinet/sctputil.c
 head/sys/netinet/sctputil.h
 head/sys/sys/sockbuf.h
 head/usr.bin/bluetooth/btsockstat/btsockstat.c
 head/usr.bin/netstat/inet.c
 head/usr.bin/netstat/netgraph.c
 head/usr.bin/netstat/unix.c
 head/usr.bin/systat/netstat.c

Modified: head/sys/dev/cxgbe/tom/t4_ddp.c
==============================================================================
--- head/sys/dev/cxgbe/tom/t4_ddp.c     Sun Nov 30 12:37:20 2014        
(r275325)
+++ head/sys/dev/cxgbe/tom/t4_ddp.c     Sun Nov 30 12:52:33 2014        
(r275326)
@@ -971,8 +971,9 @@ handle_ddp(struct socket *so, struct uio
         */
        rc = sbwait(sb);
        while (toep->ddp_flags & buf_flag) {
+               /* XXXGL: shouldn't here be sbwait() call? */
                sb->sb_flags |= SB_WAIT;
-               msleep(&sb->sb_cc, &sb->sb_mtx, PSOCK , "sbwait", 0);
+               msleep(&sb->sb_acc, &sb->sb_mtx, PSOCK , "sbwait", 0);
        }
        unwire_ddp_buffer(db);
        return (rc);

Modified: head/sys/kern/uipc_debug.c
==============================================================================
--- head/sys/kern/uipc_debug.c  Sun Nov 30 12:37:20 2014        (r275325)
+++ head/sys/kern/uipc_debug.c  Sun Nov 30 12:52:33 2014        (r275326)
@@ -401,7 +401,8 @@ db_print_sockbuf(struct sockbuf *sb, con
        db_printf("sb_sndptroff: %u\n", sb->sb_sndptroff);

        db_print_indent(indent);
-       db_printf("sb_cc: %u   ", sb->sb_cc);
+       db_printf("sb_acc: %u   ", sb->sb_acc);
+       db_printf("sb_ccc: %u   ", sb->sb_ccc);
        db_printf("sb_hiwat: %u   ", sb->sb_hiwat);
        db_printf("sb_mbcnt: %u   ", sb->sb_mbcnt);
        db_printf("sb_mbmax: %u\n", sb->sb_mbmax);

Modified: head/sys/kern/uipc_sockbuf.c
==============================================================================
--- head/sys/kern/uipc_sockbuf.c        Sun Nov 30 12:37:20 2014        
(r275325)
+++ head/sys/kern/uipc_sockbuf.c        Sun Nov 30 12:52:33 2014        
(r275326)
@@ -69,6 +69,43 @@ static struct mbuf   *sbcut_internal(struc
static void     sbflush_internal(struct sockbuf *sb);

/*
+ * Mark ready "count" mbufs starting with "m".
+ */
+int
+sbready(struct sockbuf *sb, struct mbuf *m, int count)
+{
+       u_int blocker;
+
+       SOCKBUF_LOCK_ASSERT(sb);
+       KASSERT(sb->sb_fnrdy != NULL, ("%s: sb %p NULL fnrdy", __func__, sb));
+
+       blocker = (sb->sb_fnrdy == m) ? M_BLOCKED : 0;
+
+       for (int i = 0; i < count; i++, m = m->m_next) {
+               KASSERT(m->m_flags & M_NOTREADY,
+                   ("%s: m %p !M_NOTREADY", __func__, m));
+               m->m_flags &= ~(M_NOTREADY | blocker);
+               if (blocker)
+                       sb->sb_acc += m->m_len;
+       }
+
+       if (!blocker)
+               return (EINPROGRESS);
+
+       /* This one was blocking all the queue. */
+       for (; m && (m->m_flags & M_NOTREADY) == 0; m = m->m_next) {
+               KASSERT(m->m_flags & M_BLOCKED,
+                   ("%s: m %p !M_BLOCKED", __func__, m));
+               m->m_flags &= ~M_BLOCKED;
+               sb->sb_acc += m->m_len;
+       }
+
+       sb->sb_fnrdy = m;
+
+       return (0);
+}
+
+/*
 * Adjust sockbuf state reflecting allocation of m.
 */
void
@@ -77,7 +114,15 @@ sballoc(struct sockbuf *sb, struct mbuf

        SOCKBUF_LOCK_ASSERT(sb);

-       sb->sb_cc += m->m_len;
+       sb->sb_ccc += m->m_len;
+
+       if (sb->sb_fnrdy == NULL) {
+               if (m->m_flags & M_NOTREADY)
+                       sb->sb_fnrdy = m;
+               else
+                       sb->sb_acc += m->m_len;
+       } else
+               m->m_flags |= M_BLOCKED;

        if (m->m_type != MT_DATA && m->m_type != MT_OOBDATA)
                sb->sb_ctl += m->m_len;
@@ -102,7 +147,25 @@ sbfree(struct sockbuf *sb, struct mbuf *
        SOCKBUF_LOCK_ASSERT(sb);
#endif

-       sb->sb_cc -= m->m_len;
+       sb->sb_ccc -= m->m_len;
+
+       if (!(m->m_flags & M_NOTAVAIL))
+               sb->sb_acc -= m->m_len;
+
+       if (m == sb->sb_fnrdy) {
+               struct mbuf *n;
+
+               KASSERT(m->m_flags & M_NOTREADY,
+                   ("%s: m %p !M_NOTREADY", __func__, m));
+
+               n = m->m_next;
+               while (n != NULL && !(n->m_flags & M_NOTREADY)) {
+                       n->m_flags &= ~M_BLOCKED;
+                       sb->sb_acc += n->m_len;
+                       n = n->m_next;
+               }
+               sb->sb_fnrdy = n;
+       }

        if (m->m_type != MT_DATA && m->m_type != MT_OOBDATA)
                sb->sb_ctl -= m->m_len;
@@ -181,7 +244,7 @@ sbwait(struct sockbuf *sb)
        SOCKBUF_LOCK_ASSERT(sb);

        sb->sb_flags |= SB_WAIT;
-       return (msleep_sbt(&sb->sb_cc, &sb->sb_mtx,
+       return (msleep_sbt(&sb->sb_acc, &sb->sb_mtx,
            (sb->sb_flags & SB_NOINTR) ? PSOCK : PSOCK | PCATCH, "sbwait",
            sb->sb_timeo, 0, 0));
}
@@ -238,7 +301,7 @@ sowakeup(struct socket *so, struct sockb
                sb->sb_flags &= ~SB_SEL;
        if (sb->sb_flags & SB_WAIT) {
                sb->sb_flags &= ~SB_WAIT;
-               wakeup(&sb->sb_cc);
+               wakeup(&sb->sb_acc);
        }
        KNOTE_LOCKED(&sb->sb_sel.si_note, 0);
        if (sb->sb_upcall != NULL) {
@@ -609,12 +672,13 @@ sbappendstream(struct sockbuf *sb, struc
void
sbcheck(struct sockbuf *sb, const char *file, int line)
{
-       struct mbuf *m, *n;
-       u_long cc, mbcnt;
+       struct mbuf *m, *n, *fnrdy;
+       u_long acc, ccc, mbcnt;

        SOCKBUF_LOCK_ASSERT(sb);

-       cc = mbcnt = 0;
+       acc = ccc = mbcnt = 0;
+       fnrdy = NULL;

        for (m = sb->sb_mb; m; m = n) {
            n = m->m_nextpkt;
@@ -623,15 +687,31 @@ sbcheck(struct sockbuf *sb, const char *
                        printf("sb %p empty mbuf %p\n", sb, m);
                        goto fail;
                }
-               cc += m->m_len;
+               if ((m->m_flags & M_NOTREADY) && fnrdy == NULL) {
+                       if (m != sb->sb_fnrdy) {
+                               printf("sb %p: fnrdy %p != m %p\n",
+                                   sb, sb->sb_fnrdy, m);
+                               goto fail;
+                       }
+                       fnrdy = m;
+               }
+               if (fnrdy) {
+                       if (!(m->m_flags & M_NOTAVAIL)) {
+                               printf("sb %p: fnrdy %p, m %p is avail\n",
+                                   sb, sb->sb_fnrdy, m);
+                               goto fail;
+                       }
+               } else
+                       acc += m->m_len;
+               ccc += m->m_len;
                mbcnt += MSIZE;
                if (m->m_flags & M_EXT) /*XXX*/ /* pretty sure this is bogus */
                        mbcnt += m->m_ext.ext_size;
            }
        }
-       if (cc != sb->sb_cc || mbcnt != sb->sb_mbcnt) {
-               printf("cc %ld != %u || mbcnt %ld != %u\n", cc, sb->sb_cc,
-                   mbcnt, sb->sb_mbcnt);
+       if (acc != sb->sb_acc || ccc != sb->sb_ccc || mbcnt != sb->sb_mbcnt) {
+               printf("acc %ld/%u ccc %ld/%u mbcnt %ld/%u\n",
+                   acc, sb->sb_acc, ccc, sb->sb_ccc, mbcnt, sb->sb_mbcnt);
                goto fail;
        }
        return;
@@ -832,8 +912,8 @@ sbappendcontrol(struct sockbuf *sb, stru
 *
 * (2) The mbuf may be coalesced -- i.e., data in the mbuf may be copied into
 *     an mbuf already in the socket buffer.  This can occur if an
- *     appropriate mbuf exists, there is room, and no merging of data types
- *     will occur.
+ *     appropriate mbuf exists, there is room, both mbufs are not marked as
+ *     not ready, and no merging of data types will occur.
 *
 * (3) The mbuf may be appended to the end of the existing mbuf chain.
 *
@@ -862,13 +942,17 @@ sbcompress(struct sockbuf *sb, struct mb
                if (n && (n->m_flags & M_EOR) == 0 &&
                    M_WRITABLE(n) &&
                    ((sb->sb_flags & SB_NOCOALESCE) == 0) &&
+                   !(m->m_flags & M_NOTREADY) &&
+                   !(n->m_flags & M_NOTREADY) &&
                    m->m_len <= MCLBYTES / 4 && /* XXX: Don't copy too much */
                    m->m_len <= M_TRAILINGSPACE(n) &&
                    n->m_type == m->m_type) {
                        bcopy(mtod(m, caddr_t), mtod(n, caddr_t) + n->m_len,
                            (unsigned)m->m_len);
                        n->m_len += m->m_len;
-                       sb->sb_cc += m->m_len;
+                       sb->sb_ccc += m->m_len;
+                       if (sb->sb_fnrdy == NULL)
+                               sb->sb_acc += m->m_len;
                        if (m->m_type != MT_DATA && m->m_type != MT_OOBDATA)
                                /* XXX: Probably don't need.*/
                                sb->sb_ctl += m->m_len;
@@ -905,13 +989,13 @@ sbflush_internal(struct sockbuf *sb)
                 * Don't call sbcut(sb, 0) if the leading mbuf is non-empty:
                 * we would loop forever. Panic instead.
                 */
-               if (!sb->sb_cc && (sb->sb_mb == NULL || sb->sb_mb->m_len))
+               if (sb->sb_ccc == 0 && (sb->sb_mb == NULL || sb->sb_mb->m_len))
                        break;
-               m_freem(sbcut_internal(sb, (int)sb->sb_cc));
+               m_freem(sbcut_internal(sb, (int)sb->sb_ccc));
        }
-       if (sb->sb_cc || sb->sb_mb || sb->sb_mbcnt)
-               panic("sbflush_internal: cc %u || mb %p || mbcnt %u",
-                   sb->sb_cc, (void *)sb->sb_mb, sb->sb_mbcnt);
+       KASSERT(sb->sb_ccc == 0 && sb->sb_mb == 0 && sb->sb_mbcnt == 0,
+           ("%s: ccc %u mb %p mbcnt %u", __func__,
+           sb->sb_ccc, (void *)sb->sb_mb, sb->sb_mbcnt));
}

void
@@ -937,7 +1021,7 @@ sbflush(struct sockbuf *sb)
static struct mbuf *
sbcut_internal(struct sockbuf *sb, int len)
{
-       struct mbuf *m, *n, *next, *mfree;
+       struct mbuf *m, *next, *mfree;

        next = (m = sb->sb_mb) ? m->m_nextpkt : 0;
        mfree = NULL;
@@ -949,9 +1033,12 @@ sbcut_internal(struct sockbuf *sb, int l
                        next = m->m_nextpkt;
                }
                if (m->m_len > len) {
+                       KASSERT(!(m->m_flags & M_NOTAVAIL),
+                           ("%s: m %p M_NOTAVAIL", __func__, m));
                        m->m_len -= len;
                        m->m_data += len;
-                       sb->sb_cc -= len;
+                       sb->sb_ccc -= len;
+                       sb->sb_acc -= len;
                        if (sb->sb_sndptroff != 0)
                                sb->sb_sndptroff -= len;
                        if (m->m_type != MT_DATA && m->m_type != MT_OOBDATA)
@@ -960,10 +1047,20 @@ sbcut_internal(struct sockbuf *sb, int l
                }
                len -= m->m_len;
                sbfree(sb, m);
-               n = m->m_next;
-               m->m_next = mfree;
-               mfree = m;
-               m = n;
+               /*
+                * Do not put M_NOTREADY buffers to the free list, they
+                * are referenced from outside.
+                */
+               if (m->m_flags & M_NOTREADY)
+                       m = m->m_next;
+               else {
+                       struct mbuf *n;
+
+                       n = m->m_next;
+                       m->m_next = mfree;
+                       mfree = m;
+                       m = n;
+               }
        }
        if (m) {
                sb->sb_mb = m;
@@ -1030,8 +1127,8 @@ sbsndptr(struct sockbuf *sb, u_int off,
        struct mbuf *m, *ret;

        KASSERT(sb->sb_mb != NULL, ("%s: sb_mb is NULL", __func__));
-       KASSERT(off + len <= sb->sb_cc, ("%s: beyond sb", __func__));
-       KASSERT(sb->sb_sndptroff <= sb->sb_cc, ("%s: sndptroff broken", 
__func__));
+       KASSERT(off + len <= sb->sb_acc, ("%s: beyond sb", __func__));
+       KASSERT(sb->sb_sndptroff <= sb->sb_acc, ("%s: sndptroff broken", 
__func__));

        /*
         * Is off below stored offset? Happens on retransmits.
@@ -1180,7 +1277,7 @@ void
sbtoxsockbuf(struct sockbuf *sb, struct xsockbuf *xsb)
{

-       xsb->sb_cc = sb->sb_cc;
+       xsb->sb_cc = sb->sb_ccc;
        xsb->sb_hiwat = sb->sb_hiwat;
        xsb->sb_mbcnt = sb->sb_mbcnt;
        xsb->sb_mcnt = sb->sb_mcnt;

Modified: head/sys/kern/uipc_socket.c
==============================================================================
--- head/sys/kern/uipc_socket.c Sun Nov 30 12:37:20 2014        (r275325)
+++ head/sys/kern/uipc_socket.c Sun Nov 30 12:52:33 2014        (r275326)
@@ -1706,7 +1706,8 @@ dontblock:
         */
        moff = 0;
        offset = 0;
-       while (m != NULL && uio->uio_resid > 0 && error == 0) {
+       while (m != NULL && !(m->m_flags & M_NOTAVAIL) && uio->uio_resid > 0
+           && error == 0) {
                /*
                 * If the type of mbuf has changed since the last mbuf
                 * examined ('type'), end the receive operation.
@@ -2044,6 +2045,8 @@ deliver:
                        for (m = sb->sb_mb;
                             m != NULL && m->m_len <= len;
                             m = m->m_next) {
+                               KASSERT(!(m->m_flags & M_NOTAVAIL),
+                                   ("%s: m %p not available", __func__, m));
                                len -= m->m_len;
                                uio->uio_resid -= m->m_len;
                                sbfree(sb, m);

Modified: head/sys/netinet/sctp_indata.c
==============================================================================
--- head/sys/netinet/sctp_indata.c      Sun Nov 30 12:37:20 2014        
(r275325)
+++ head/sys/netinet/sctp_indata.c      Sun Nov 30 12:52:33 2014        
(r275326)
@@ -70,14 +70,14 @@ sctp_calc_rwnd(struct sctp_tcb *stcb, st

        /*
         * This is really set wrong with respect to a 1-2-m socket. Since
-        * the sb_cc is the count that everyone as put up. When we re-write
+        * the sb_ccc is the count that everyone as put up. When we re-write
         * sctp_soreceive then we will fix this so that ONLY this
         * associations data is taken into account.
         */
        if (stcb->sctp_socket == NULL)
                return (calc);

-       if (stcb->asoc.sb_cc == 0 &&
+       if (stcb->asoc.sb_ccc == 0 &&
            asoc->size_on_reasm_queue == 0 &&
            asoc->size_on_all_streams == 0) {
                /* Full rwnd granted */
@@ -1363,7 +1363,7 @@ sctp_process_a_data_chunk(struct sctp_tc
                 * When we have NO room in the rwnd we check to make sure
                 * the reader is doing its job...
                 */
-               if (stcb->sctp_socket->so_rcv.sb_cc) {
+               if (stcb->sctp_socket->so_rcv.sb_ccc) {
                        /* some to read, wake-up */
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                        struct socket *so;

Modified: head/sys/netinet/sctp_input.c
==============================================================================
--- head/sys/netinet/sctp_input.c       Sun Nov 30 12:37:20 2014        
(r275325)
+++ head/sys/netinet/sctp_input.c       Sun Nov 30 12:52:33 2014        
(r275326)
@@ -1032,7 +1032,7 @@ sctp_handle_shutdown_ack(struct sctp_shu
        if (stcb->sctp_socket) {
                if ((stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_TCPTYPE) ||
                    (stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_IN_TCPPOOL)) {
-                       stcb->sctp_socket->so_snd.sb_cc = 0;
+                       stcb->sctp_socket->so_snd.sb_ccc = 0;
                }
                sctp_ulp_notify(SCTP_NOTIFY_ASSOC_DOWN, stcb, 0, NULL, 
SCTP_SO_NOT_LOCKED);
        }

Modified: head/sys/netinet/sctp_os_bsd.h
==============================================================================
--- head/sys/netinet/sctp_os_bsd.h      Sun Nov 30 12:37:20 2014        
(r275325)
+++ head/sys/netinet/sctp_os_bsd.h      Sun Nov 30 12:52:33 2014        
(r275326)
@@ -399,7 +399,7 @@ typedef struct callout sctp_os_timer_t;
#define SCTP_SOWAKEUP(so)       wakeup(&(so)->so_timeo)
/* clear the socket buffer state */
#define SCTP_SB_CLEAR(sb)       \
-       (sb).sb_cc = 0;         \
+       (sb).sb_ccc = 0;                \
        (sb).sb_mb = NULL;      \
        (sb).sb_mbcnt = 0;


Modified: head/sys/netinet/sctp_output.c
==============================================================================
--- head/sys/netinet/sctp_output.c      Sun Nov 30 12:37:20 2014        
(r275325)
+++ head/sys/netinet/sctp_output.c      Sun Nov 30 12:52:33 2014        
(r275326)
@@ -7250,7 +7250,7 @@ one_more_time:
                        if ((stcb->sctp_socket != NULL) && \
                            ((stcb->sctp_ep->sctp_flags & 
SCTP_PCB_FLAGS_TCPTYPE) ||
                            (stcb->sctp_ep->sctp_flags & 
SCTP_PCB_FLAGS_IN_TCPPOOL))) {
-                               
atomic_subtract_int(&stcb->sctp_socket->so_snd.sb_cc, sp->length);
+                               
atomic_subtract_int(&stcb->sctp_socket->so_snd.sb_ccc, sp->length);
                        }
                        if (sp->data) {
                                sctp_m_freem(sp->data);
@@ -11532,7 +11532,7 @@ jump_out:
                drp->current_onq = htonl(asoc->size_on_reasm_queue +
                    asoc->size_on_all_streams +
                    asoc->my_rwnd_control_len +
-                   stcb->sctp_socket->so_rcv.sb_cc);
+                   stcb->sctp_socket->so_rcv.sb_ccc);
        } else {
                /*-
                 * If my rwnd is 0, possibly from mbuf depletion as well as

Modified: head/sys/netinet/sctp_pcb.c
==============================================================================
--- head/sys/netinet/sctp_pcb.c Sun Nov 30 12:37:20 2014        (r275325)
+++ head/sys/netinet/sctp_pcb.c Sun Nov 30 12:52:33 2014        (r275326)
@@ -3397,7 +3397,7 @@ sctp_inpcb_free(struct sctp_inpcb *inp,
                        if ((asoc->asoc.size_on_reasm_queue > 0) ||
                            (asoc->asoc.control_pdapi) ||
                            (asoc->asoc.size_on_all_streams > 0) ||
-                           (so && (so->so_rcv.sb_cc > 0))) {
+                           (so && (so->so_rcv.sb_ccc > 0))) {
                                /* Left with Data unread */
                                struct mbuf *op_err;

@@ -3625,7 +3625,7 @@ sctp_inpcb_free(struct sctp_inpcb *inp,
                TAILQ_REMOVE(&inp->read_queue, sq, next);
                sctp_free_remote_addr(sq->whoFrom);
                if (so)
-                       so->so_rcv.sb_cc -= sq->length;
+                       so->so_rcv.sb_ccc -= sq->length;
                if (sq->data) {
                        sctp_m_freem(sq->data);
                        sq->data = NULL;
@@ -4853,7 +4853,7 @@ sctp_free_assoc(struct sctp_inpcb *inp,
                        inp->sctp_flags |= SCTP_PCB_FLAGS_WAS_CONNECTED;
                        if (so) {
                                SOCK_LOCK(so);
-                               if (so->so_rcv.sb_cc == 0) {
+                               if (so->so_rcv.sb_ccc == 0) {
                                        so->so_state &= ~(SS_ISCONNECTING |
                                            SS_ISDISCONNECTING |
                                            SS_ISCONFIRMING |

Modified: head/sys/netinet/sctp_pcb.h
==============================================================================
--- head/sys/netinet/sctp_pcb.h Sun Nov 30 12:37:20 2014        (r275325)
+++ head/sys/netinet/sctp_pcb.h Sun Nov 30 12:52:33 2014        (r275326)
@@ -369,7 +369,7 @@ struct sctp_inpcb {
        }     ip_inp;


-       /* Socket buffer lock protects read_queue and of course sb_cc */
+       /* Socket buffer lock protects read_queue and of course sb_ccc */
        struct sctp_readhead read_queue;

                      LIST_ENTRY(sctp_inpcb) sctp_list; /* lists all endpoints 
*/

Modified: head/sys/netinet/sctp_structs.h
==============================================================================
--- head/sys/netinet/sctp_structs.h     Sun Nov 30 12:37:20 2014        
(r275325)
+++ head/sys/netinet/sctp_structs.h     Sun Nov 30 12:52:33 2014        
(r275326)
@@ -990,7 +990,7 @@ struct sctp_association {

        uint32_t total_output_queue_size;

-       uint32_t sb_cc;         /* shadow of sb_cc */
+       uint32_t sb_ccc;                /* shadow of sb_ccc */
        uint32_t sb_send_resv;  /* amount reserved on a send */
        uint32_t my_rwnd_control_len;   /* shadow of sb_mbcnt used for rwnd
                                         * control */

Modified: head/sys/netinet/sctp_usrreq.c
==============================================================================
--- head/sys/netinet/sctp_usrreq.c      Sun Nov 30 12:37:20 2014        
(r275325)
+++ head/sys/netinet/sctp_usrreq.c      Sun Nov 30 12:52:33 2014        
(r275326)
@@ -586,7 +586,7 @@ sctp_must_try_again:
        if (((flags & SCTP_PCB_FLAGS_SOCKET_GONE) == 0) &&
            (atomic_cmpset_int(&inp->sctp_flags, flags, (flags | 
SCTP_PCB_FLAGS_SOCKET_GONE | SCTP_PCB_FLAGS_CLOSE_IP)))) {
                if (((so->so_options & SO_LINGER) && (so->so_linger == 0)) ||
-                   (so->so_rcv.sb_cc > 0)) {
+                   (so->so_rcv.sb_ccc > 0)) {
#ifdef SCTP_LOG_CLOSING
                        sctp_log_closing(inp, NULL, 13);
#endif
@@ -751,7 +751,7 @@ sctp_disconnect(struct socket *so)
                        }
                        if (((so->so_options & SO_LINGER) &&
                            (so->so_linger == 0)) ||
-                           (so->so_rcv.sb_cc > 0)) {
+                           (so->so_rcv.sb_ccc > 0)) {
                                if (SCTP_GET_STATE(asoc) !=
                                    SCTP_STATE_COOKIE_WAIT) {
                                        /* Left with Data unread */
@@ -916,7 +916,7 @@ sctp_flush(struct socket *so, int how)
                inp->sctp_flags |= SCTP_PCB_FLAGS_SOCKET_CANT_READ;
                SCTP_INP_READ_UNLOCK(inp);
                SCTP_INP_WUNLOCK(inp);
-               so->so_rcv.sb_cc = 0;
+               so->so_rcv.sb_ccc = 0;
                so->so_rcv.sb_mbcnt = 0;
                so->so_rcv.sb_mb = NULL;
        }
@@ -925,7 +925,7 @@ sctp_flush(struct socket *so, int how)
                 * First make sure the sb will be happy, we don't use these
                 * except maybe the count
                 */
-               so->so_snd.sb_cc = 0;
+               so->so_snd.sb_ccc = 0;
                so->so_snd.sb_mbcnt = 0;
                so->so_snd.sb_mb = NULL;


Modified: head/sys/netinet/sctp_var.h
==============================================================================
--- head/sys/netinet/sctp_var.h Sun Nov 30 12:37:20 2014        (r275325)
+++ head/sys/netinet/sctp_var.h Sun Nov 30 12:52:33 2014        (r275326)
@@ -82,9 +82,9 @@ extern struct pr_usrreqs sctp_usrreqs;

#define sctp_maxspace(sb) (max((sb)->sb_hiwat,SCTP_MINIMAL_RWND))

-#define        sctp_sbspace(asoc, sb) ((long) ((sctp_maxspace(sb) > 
(asoc)->sb_cc) ? (sctp_maxspace(sb) - (asoc)->sb_cc) : 0))
+#define        sctp_sbspace(asoc, sb) ((long) ((sctp_maxspace(sb) > 
(asoc)->sb_ccc) ? (sctp_maxspace(sb) - (asoc)->sb_ccc) : 0))

-#define        sctp_sbspace_failedmsgs(sb) ((long) ((sctp_maxspace(sb) > 
(sb)->sb_cc) ? (sctp_maxspace(sb) - (sb)->sb_cc) : 0))
+#define        sctp_sbspace_failedmsgs(sb) ((long) ((sctp_maxspace(sb) > 
(sb)->sb_ccc) ? (sctp_maxspace(sb) - (sb)->sb_ccc) : 0))

#define sctp_sbspace_sub(a,b) ((a > b) ? (a - b) : 0)

@@ -195,10 +195,10 @@ extern struct pr_usrreqs sctp_usrreqs;
}

#define sctp_sbfree(ctl, stcb, sb, m) { \
-       SCTP_SAVE_ATOMIC_DECREMENT(&(sb)->sb_cc, SCTP_BUF_LEN((m))); \
+       SCTP_SAVE_ATOMIC_DECREMENT(&(sb)->sb_ccc, SCTP_BUF_LEN((m))); \
        SCTP_SAVE_ATOMIC_DECREMENT(&(sb)->sb_mbcnt, MSIZE); \
        if (((ctl)->do_not_ref_stcb == 0) && stcb) {\
-               SCTP_SAVE_ATOMIC_DECREMENT(&(stcb)->asoc.sb_cc, 
SCTP_BUF_LEN((m))); \
+               SCTP_SAVE_ATOMIC_DECREMENT(&(stcb)->asoc.sb_ccc, 
SCTP_BUF_LEN((m))); \
                SCTP_SAVE_ATOMIC_DECREMENT(&(stcb)->asoc.my_rwnd_control_len, 
MSIZE); \
        } \
        if (SCTP_BUF_TYPE(m) != MT_DATA && SCTP_BUF_TYPE(m) != MT_HEADER && \
@@ -207,10 +207,10 @@ extern struct pr_usrreqs sctp_usrreqs;
}

#define sctp_sballoc(stcb, sb, m) { \
-       atomic_add_int(&(sb)->sb_cc,SCTP_BUF_LEN((m))); \
+       atomic_add_int(&(sb)->sb_ccc,SCTP_BUF_LEN((m))); \
        atomic_add_int(&(sb)->sb_mbcnt, MSIZE); \
        if (stcb) { \
-               atomic_add_int(&(stcb)->asoc.sb_cc,SCTP_BUF_LEN((m))); \
+               atomic_add_int(&(stcb)->asoc.sb_ccc,SCTP_BUF_LEN((m))); \
                atomic_add_int(&(stcb)->asoc.my_rwnd_control_len, MSIZE); \
        } \
        if (SCTP_BUF_TYPE(m) != MT_DATA && SCTP_BUF_TYPE(m) != MT_HEADER && \

Modified: head/sys/netinet/sctputil.c
==============================================================================
--- head/sys/netinet/sctputil.c Sun Nov 30 12:37:20 2014        (r275325)
+++ head/sys/netinet/sctputil.c Sun Nov 30 12:52:33 2014        (r275326)
@@ -67,9 +67,9 @@ sctp_sblog(struct sockbuf *sb, struct sc
        struct sctp_cwnd_log sctp_clog;

        sctp_clog.x.sb.stcb = stcb;
-       sctp_clog.x.sb.so_sbcc = sb->sb_cc;
+       sctp_clog.x.sb.so_sbcc = sb->sb_ccc;
        if (stcb)
-               sctp_clog.x.sb.stcb_sbcc = stcb->asoc.sb_cc;
+               sctp_clog.x.sb.stcb_sbcc = stcb->asoc.sb_ccc;
        else
                sctp_clog.x.sb.stcb_sbcc = 0;
        sctp_clog.x.sb.incr = incr;
@@ -4363,7 +4363,7 @@ sctp_add_to_readq(struct sctp_inpcb *inp
{
        /*
         * Here we must place the control on the end of the socket read
-        * queue AND increment sb_cc so that select will work properly on
+        * queue AND increment sb_ccc so that select will work properly on
         * read.
         */
        struct mbuf *m, *prev = NULL;
@@ -4489,7 +4489,7 @@ sctp_append_to_readq(struct sctp_inpcb *
         * the reassembly queue.
         *
         * If PDAPI this means we need to add m to the end of the data.
-        * Increase the length in the control AND increment the sb_cc.
+        * Increase the length in the control AND increment the sb_ccc.
         * Otherwise sb is NULL and all we need to do is put it at the end
         * of the mbuf chain.
         */
@@ -4701,10 +4701,10 @@ sctp_free_bufspace(struct sctp_tcb *stcb

        if (stcb->sctp_socket && (((stcb->sctp_ep->sctp_flags & 
SCTP_PCB_FLAGS_IN_TCPPOOL)) ||
            ((stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_TCPTYPE)))) {
-               if (stcb->sctp_socket->so_snd.sb_cc >= tp1->book_size) {
-                       stcb->sctp_socket->so_snd.sb_cc -= tp1->book_size;
+               if (stcb->sctp_socket->so_snd.sb_ccc >= tp1->book_size) {
+                       stcb->sctp_socket->so_snd.sb_ccc -= tp1->book_size;
                } else {
-                       stcb->sctp_socket->so_snd.sb_cc = 0;
+                       stcb->sctp_socket->so_snd.sb_ccc = 0;

                }
        }
@@ -5254,11 +5254,11 @@ sctp_sorecvmsg(struct socket *so,
        in_eeor_mode = sctp_is_feature_on(inp, SCTP_PCB_FLAGS_EXPLICIT_EOR);
        if (SCTP_BASE_SYSCTL(sctp_logging_level) & 
SCTP_RECV_RWND_LOGGING_ENABLE) {
                sctp_misc_ints(SCTP_SORECV_ENTER,
-                   rwnd_req, in_eeor_mode, so->so_rcv.sb_cc, uio->uio_resid);
+                   rwnd_req, in_eeor_mode, so->so_rcv.sb_ccc, uio->uio_resid);
        }
        if (SCTP_BASE_SYSCTL(sctp_logging_level) & 
SCTP_RECV_RWND_LOGGING_ENABLE) {
                sctp_misc_ints(SCTP_SORECV_ENTERPL,
-                   rwnd_req, block_allowed, so->so_rcv.sb_cc, uio->uio_resid);
+                   rwnd_req, block_allowed, so->so_rcv.sb_ccc, uio->uio_resid);
        }
        error = sblock(&so->so_rcv, (block_allowed ? SBL_WAIT : 0));
        if (error) {
@@ -5277,23 +5277,23 @@ restart_nosblocks:
            (inp->sctp_flags & SCTP_PCB_FLAGS_SOCKET_ALLGONE)) {
                goto out;
        }
-       if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) && (so->so_rcv.sb_cc == 0)) 
{
+       if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) && (so->so_rcv.sb_ccc == 
0)) {
                if (so->so_error) {
                        error = so->so_error;
                        if ((in_flags & MSG_PEEK) == 0)
                                so->so_error = 0;
                        goto out;
                } else {
-                       if (so->so_rcv.sb_cc == 0) {
+                       if (so->so_rcv.sb_ccc == 0) {
                                /* indicate EOF */
                                error = 0;
                                goto out;
                        }
                }
        }
-       if ((so->so_rcv.sb_cc <= held_length) && block_allowed) {
+       if ((so->so_rcv.sb_ccc <= held_length) && block_allowed) {
                /* we need to wait for data */
-               if ((so->so_rcv.sb_cc == 0) &&
+               if ((so->so_rcv.sb_ccc == 0) &&
                    ((inp->sctp_flags & SCTP_PCB_FLAGS_TCPTYPE) ||
                    (inp->sctp_flags & SCTP_PCB_FLAGS_IN_TCPPOOL))) {
                        if ((inp->sctp_flags & SCTP_PCB_FLAGS_CONNECTED) == 0) {
@@ -5329,7 +5329,7 @@ restart_nosblocks:
                }
                held_length = 0;
                goto restart_nosblocks;
-       } else if (so->so_rcv.sb_cc == 0) {
+       } else if (so->so_rcv.sb_ccc == 0) {
                if (so->so_error) {
                        error = so->so_error;
                        if ((in_flags & MSG_PEEK) == 0)
@@ -5386,11 +5386,11 @@ restart_nosblocks:
                        SCTP_INP_READ_LOCK(inp);
                }
                control = TAILQ_FIRST(&inp->read_queue);
-               if ((control == NULL) && (so->so_rcv.sb_cc != 0)) {
+               if ((control == NULL) && (so->so_rcv.sb_ccc != 0)) {
#ifdef INVARIANTS
                        panic("Huh, its non zero and nothing on control?");
#endif
-                       so->so_rcv.sb_cc = 0;
+                       so->so_rcv.sb_ccc = 0;
                }
                SCTP_INP_READ_UNLOCK(inp);
                hold_rlock = 0;
@@ -5511,11 +5511,11 @@ restart_nosblocks:
                }
                /*
                 * if we reach here, not suitable replacement is available
-                * <or> fragment interleave is NOT on. So stuff the sb_cc
+                * <or> fragment interleave is NOT on. So stuff the sb_ccc
                 * into the our held count, and its time to sleep again.
                 */
-               held_length = so->so_rcv.sb_cc;
-               control->held_length = so->so_rcv.sb_cc;
+               held_length = so->so_rcv.sb_ccc;
+               control->held_length = so->so_rcv.sb_ccc;
                goto restart;
        }
        /* Clear the held length since there is something to read */
@@ -5812,10 +5812,10 @@ get_more_data:
                                        if (SCTP_BASE_SYSCTL(sctp_logging_level) 
& SCTP_SB_LOGGING_ENABLE) {
                                                sctp_sblog(&so->so_rcv, 
control->do_not_ref_stcb ? NULL : stcb, SCTP_LOG_SBFREE, cp_len);
                                        }
-                                       atomic_subtract_int(&so->so_rcv.sb_cc, 
cp_len);
+                                       atomic_subtract_int(&so->so_rcv.sb_ccc, 
cp_len);
                                        if ((control->do_not_ref_stcb == 0) &&
                                            stcb) {
-                                               
atomic_subtract_int(&stcb->asoc.sb_cc, cp_len);
+                                               
atomic_subtract_int(&stcb->asoc.sb_ccc, cp_len);
                                        }
                                        copied_so_far += cp_len;
                                        freed_so_far += cp_len;
@@ -5960,7 +5960,7 @@ wait_some_more:
                    (sctp_is_feature_on(inp, SCTP_PCB_FLAGS_FRAG_INTERLEAVE))) {
                        goto release;
                }
-               if (so->so_rcv.sb_cc <= control->held_length) {
+               if (so->so_rcv.sb_ccc <= control->held_length) {
                        error = sbwait(&so->so_rcv);
                        if (error) {
                                goto release;
@@ -5987,8 +5987,8 @@ wait_some_more:
                                }
                                goto done_with_control;
                        }
-                       if (so->so_rcv.sb_cc > held_length) {
-                               control->held_length = so->so_rcv.sb_cc;
+                       if (so->so_rcv.sb_ccc > held_length) {
+                               control->held_length = so->so_rcv.sb_ccc;
                                held_length = 0;
                        }
                        goto wait_some_more;
@@ -6135,13 +6135,13 @@ out:
                            freed_so_far,
                            ((uio) ? (slen - uio->uio_resid) : slen),
                            stcb->asoc.my_rwnd,
-                           so->so_rcv.sb_cc);
+                           so->so_rcv.sb_ccc);
                } else {
                        sctp_misc_ints(SCTP_SORECV_DONE,
                            freed_so_far,
                            ((uio) ? (slen - uio->uio_resid) : slen),
                            0,
-                           so->so_rcv.sb_cc);
+                           so->so_rcv.sb_ccc);
                }
        }
stage_left:

Modified: head/sys/netinet/sctputil.h
==============================================================================
--- head/sys/netinet/sctputil.h Sun Nov 30 12:37:20 2014        (r275325)
+++ head/sys/netinet/sctputil.h Sun Nov 30 12:52:33 2014        (r275326)
@@ -286,10 +286,10 @@ do { \
                } \
                if (stcb->sctp_socket && ((stcb->sctp_ep->sctp_flags & 
SCTP_PCB_FLAGS_TCPTYPE) || \
                    (stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_IN_TCPPOOL))) { 
\
-                       if (stcb->sctp_socket->so_snd.sb_cc >= tp1->book_size) 
{ \
-                               
atomic_subtract_int(&((stcb)->sctp_socket->so_snd.sb_cc), tp1->book_size); \
+                       if (stcb->sctp_socket->so_snd.sb_ccc >= tp1->book_size) 
{ \
+                               
atomic_subtract_int(&((stcb)->sctp_socket->so_snd.sb_ccc), tp1->book_size); \
                        } else { \
-                               stcb->sctp_socket->so_snd.sb_cc = 0; \
+                               stcb->sctp_socket->so_snd.sb_ccc = 0; \
                        } \
                } \
        } \
@@ -307,10 +307,10 @@ do { \
                } \
                if (stcb->sctp_socket && ((stcb->sctp_ep->sctp_flags & 
SCTP_PCB_FLAGS_TCPTYPE) || \
                    (stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_IN_TCPPOOL))) { 
\
-                       if (stcb->sctp_socket->so_snd.sb_cc >= sp->length) { \
-                               
atomic_subtract_int(&stcb->sctp_socket->so_snd.sb_cc,sp->length); \
+                       if (stcb->sctp_socket->so_snd.sb_ccc >= sp->length) { \
+                               
atomic_subtract_int(&stcb->sctp_socket->so_snd.sb_ccc,sp->length); \
                        } else { \
-                               stcb->sctp_socket->so_snd.sb_cc = 0; \
+                               stcb->sctp_socket->so_snd.sb_ccc = 0; \
                        } \
                } \
        } \
@@ -322,7 +322,7 @@ do { \
        if ((stcb->sctp_socket != NULL) && \
            ((stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_TCPTYPE) || \
             (stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_IN_TCPPOOL))) { \
-               atomic_add_int(&stcb->sctp_socket->so_snd.sb_cc,sz); \
+               atomic_add_int(&stcb->sctp_socket->so_snd.sb_ccc,sz); \
        } \
} while (0)


Modified: head/sys/sys/sockbuf.h
==============================================================================
--- head/sys/sys/sockbuf.h      Sun Nov 30 12:37:20 2014        (r275325)
+++ head/sys/sys/sockbuf.h      Sun Nov 30 12:52:33 2014        (r275326)
@@ -89,8 +89,10 @@ struct       sockbuf {
        struct  mbuf *sb_lastrecord;    /* (c/d) first mbuf of last
                                         * record in socket buffer */
        struct  mbuf *sb_sndptr; /* (c/d) pointer into mbuf chain */
+       struct  mbuf *sb_fnrdy; /* (c/d) pointer to first not ready buffer */
        u_int   sb_sndptroff;   /* (c/d) byte offset of ptr into chain */
-       u_int   sb_cc;          /* (c/d) actual chars in buffer */
+       u_int   sb_acc;         /* (c/d) available chars in buffer */
+       u_int   sb_ccc;         /* (c/d) claimed chars in buffer */
        u_int   sb_hiwat;       /* (c/d) max actual char count */
        u_int   sb_mbcnt;       /* (c/d) chars of mbufs used */
        u_int   sb_mcnt;        /* (c/d) number of mbufs in buffer */
@@ -120,6 +122,13 @@ struct     sockbuf {
#define SOCKBUF_LOCK_ASSERT(_sb)        mtx_assert(SOCKBUF_MTX(_sb), MA_OWNED)
#define SOCKBUF_UNLOCK_ASSERT(_sb)      mtx_assert(SOCKBUF_MTX(_sb), 
MA_NOTOWNED)

+/*
+ * Socket buffer private mbuf(9) flags.
+ */
+#define        M_NOTREADY      M_PROTO1        /* m_data not populated yet */
+#define        M_BLOCKED       M_PROTO2        /* M_NOTREADY in front of m */
+#define        M_NOTAVAIL      (M_NOTREADY | M_BLOCKED)
+
void    sbappend(struct sockbuf *sb, struct mbuf *m);
void    sbappend_locked(struct sockbuf *sb, struct mbuf *m);
void    sbappendstream(struct sockbuf *sb, struct mbuf *m);
@@ -165,10 +174,11 @@ int       sblock(struct sockbuf *sb, int flags
void    sbunlock(struct sockbuf *sb);
void    sballoc(struct sockbuf *, struct mbuf *);
void    sbfree(struct sockbuf *, struct mbuf *);
+int    sbready(struct sockbuf *, struct mbuf *, int);

/*
 * Return how much data is available to be taken out of socket
- * bufffer right now.
+ * buffer right now.
 */
static inline u_int
sbavail(struct sockbuf *sb)
@@ -177,7 +187,7 @@ sbavail(struct sockbuf *sb)
#if 0
        SOCKBUF_LOCK_ASSERT(sb);
#endif
-       return (sb->sb_cc);
+       return (sb->sb_acc);
}

/*
@@ -191,27 +201,30 @@ sbused(struct sockbuf *sb)
#if 0
        SOCKBUF_LOCK_ASSERT(sb);
#endif
-       return (sb->sb_cc);
+       return (sb->sb_ccc);
}

/*
 * How much space is there in a socket buffer (so->so_snd or so->so_rcv)?
 * This is problematical if the fields are unsigned, as the space might
- * still be negative (cc > hiwat or mbcnt > mbmax).  Should detect
- * overflow and return 0.  Should use "lmin" but it doesn't exist now.
+ * still be negative (ccc > hiwat or mbcnt > mbmax).
 */
-static __inline
-long
+static inline long
sbspace(struct sockbuf *sb)
{
-       long bleft;
-       long mleft;
+       long bleft, mleft;
+
+#if 0
+       SOCKBUF_LOCK_ASSERT(sb);
+#endif

        if (sb->sb_flags & SB_STOP)
                return(0);
-       bleft = sb->sb_hiwat - sb->sb_cc;
+
+       bleft = sb->sb_hiwat - sb->sb_ccc;
        mleft = sb->sb_mbmax - sb->sb_mbcnt;
-       return((bleft < mleft) ? bleft : mleft);
+
+       return ((bleft < mleft) ? bleft : mleft);
}

#define SB_EMPTY_FIXUP(sb) do {                                         \

Modified: head/usr.bin/bluetooth/btsockstat/btsockstat.c
==============================================================================
--- head/usr.bin/bluetooth/btsockstat/btsockstat.c      Sun Nov 30 12:37:20 
2014        (r275325)
+++ head/usr.bin/bluetooth/btsockstat/btsockstat.c      Sun Nov 30 12:52:33 
2014        (r275326)
@@ -255,8 +255,8 @@ hcirawpr(kvm_t *kvmd, u_long addr)
                        (unsigned long) pcb.so,
                        (unsigned long) this,
                        pcb.flags,
-                       so.so_rcv.sb_cc,
-                       so.so_snd.sb_cc,
+                       so.so_rcv.sb_ccc,
+                       so.so_snd.sb_ccc,
                        pcb.addr.hci_node);
        }
} /* hcirawpr */
@@ -303,8 +303,8 @@ l2caprawpr(kvm_t *kvmd, u_long addr)
"%-8lx %-8lx %6d %6d %-17.17s\n",
                        (unsigned long) pcb.so,
                        (unsigned long) this,
-                       so.so_rcv.sb_cc,
-                       so.so_snd.sb_cc,
+                       so.so_rcv.sb_ccc,
+                       so.so_snd.sb_ccc,
                        bdaddrpr(&pcb.src, NULL, 0));
        }
} /* l2caprawpr */
@@ -361,8 +361,8 @@ l2cappr(kvm_t *kvmd, u_long addr)
                fprintf(stdout,
"%-8lx %6d %6d %-17.17s/%-5d %-17.17s %-5d %s\n",
                        (unsigned long) this,
-                       so.so_rcv.sb_cc,
-                       so.so_snd.sb_cc,
+                       so.so_rcv.sb_ccc,
+                       so.so_snd.sb_ccc,
                        bdaddrpr(&pcb.src, local, sizeof(local)),
                        pcb.psm,
                        bdaddrpr(&pcb.dst, remote, sizeof(remote)),
@@ -467,8 +467,8 @@ rfcommpr(kvm_t *kvmd, u_long addr)
                fprintf(stdout,
"%-8lx %6d %6d %-17.17s %-17.17s %-4d %-4d %s\n",
                        (unsigned long) this,
-                       so.so_rcv.sb_cc,
-                       so.so_snd.sb_cc,
+                       so.so_rcv.sb_ccc,
+                       so.so_snd.sb_ccc,
                        bdaddrpr(&pcb.src, local, sizeof(local)),
                        bdaddrpr(&pcb.dst, remote, sizeof(remote)),
                        pcb.channel,

Modified: head/usr.bin/netstat/inet.c
==============================================================================
--- head/usr.bin/netstat/inet.c Sun Nov 30 12:37:20 2014        (r275325)
+++ head/usr.bin/netstat/inet.c Sun Nov 30 12:52:33 2014        (r275326)
@@ -137,7 +137,7 @@ pcblist_sysctl(int proto, const char *na
static void
sbtoxsockbuf(struct sockbuf *sb, struct xsockbuf *xsb)
{
-       xsb->sb_cc = sb->sb_cc;
+       xsb->sb_cc = sb->sb_ccc;
        xsb->sb_hiwat = sb->sb_hiwat;
        xsb->sb_mbcnt = sb->sb_mbcnt;
        xsb->sb_mcnt = sb->sb_mcnt;
@@ -479,7 +479,8 @@ protopr(u_long off, const char *name, in
                                printf("%6u %6u %6u ", tp->t_sndrexmitpack,
                                       tp->t_rcvoopack, tp->t_sndzerowin);
                } else {
-                       printf("%6u %6u ", so->so_rcv.sb_cc, so->so_snd.sb_cc);
+                       printf("%6u %6u ",
+                           so->so_rcv.sb_cc, so->so_snd.sb_cc);
                }
                if (numeric_port) {
                        if (inp->inp_vflag & INP_IPV4) {

Modified: head/usr.bin/netstat/netgraph.c
==============================================================================
--- head/usr.bin/netstat/netgraph.c     Sun Nov 30 12:37:20 2014        
(r275325)
+++ head/usr.bin/netstat/netgraph.c     Sun Nov 30 12:52:33 2014        
(r275326)
@@ -119,7 +119,7 @@ netgraphprotopr(u_long off, const char *
                if (Aflag)
                        printf("%8lx ", (u_long) this);
                printf("%-5.5s %6u %6u ",
-                   name, sockb.so_rcv.sb_cc, sockb.so_snd.sb_cc);
+                   name, sockb.so_rcv.sb_ccc, sockb.so_snd.sb_ccc);

                /* Get info on associated node */
                if (ngpcb.node_id == 0 || csock == -1)

Modified: head/usr.bin/netstat/unix.c
==============================================================================
--- head/usr.bin/netstat/unix.c Sun Nov 30 12:37:20 2014        (r275325)
+++ head/usr.bin/netstat/unix.c Sun Nov 30 12:52:33 2014        (r275326)
@@ -287,7 +287,8 @@ unixdomainpr(struct xunpcb *xunp, struct
        } else {
                printf("%8lx %-6.6s %6u %6u %8lx %8lx %8lx %8lx",
                    (long)so->so_pcb, socktype[so->so_type], so->so_rcv.sb_cc,
-                   so->so_snd.sb_cc, (long)unp->unp_vnode, (long)unp->unp_conn,
+                   so->so_snd.sb_cc, (long)unp->unp_vnode,
+                   (long)unp->unp_conn,
                    (long)LIST_FIRST(&unp->unp_refs),
                    (long)LIST_NEXT(unp, unp_reflink));
        }

Modified: head/usr.bin/systat/netstat.c
==============================================================================
--- head/usr.bin/systat/netstat.c       Sun Nov 30 12:37:20 2014        
(r275325)
+++ head/usr.bin/systat/netstat.c       Sun Nov 30 12:52:33 2014        
(r275326)
@@ -333,8 +333,8 @@ enter_kvm(struct inpcb *inp, struct sock
        struct netinfo *p;

        if ((p = enter(inp, state, proto)) != NULL) {
-               p->ni_rcvcc = so->so_rcv.sb_cc;
-               p->ni_sndcc = so->so_snd.sb_cc;
+               p->ni_rcvcc = so->so_rcv.sb_ccc;
+               p->ni_sndcc = so->so_snd.sb_ccc;
        }
}



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