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Date:      Wed, 27 Jul 2016 09:27:08 +0000 (UTC)
From:      Sepherosa Ziehau <sephe@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r303379 - in head/sys: conf dev/hyperv/vmbus modules/hyperv/vmbus
Message-ID:  <201607270927.u6R9R829037036@repo.freebsd.org>

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Author: sephe
Date: Wed Jul 27 09:27:08 2016
New Revision: 303379
URL: https://svnweb.freebsd.org/changeset/base/303379

Log:
  hyperv/vmbus: Rename cleaned up bufring code
  
  MFC after:	1 week
  Sponsored by:	Microsoft
  Differential Revision:	https://reviews.freebsd.org/D7318

Added:
  head/sys/dev/hyperv/vmbus/vmbus_br.c
     - copied unchanged from r303378, head/sys/dev/hyperv/vmbus/hv_ring_buffer.c
Deleted:
  head/sys/dev/hyperv/vmbus/hv_ring_buffer.c
Modified:
  head/sys/conf/files.amd64
  head/sys/conf/files.i386
  head/sys/modules/hyperv/vmbus/Makefile

Modified: head/sys/conf/files.amd64
==============================================================================
--- head/sys/conf/files.amd64	Wed Jul 27 09:26:46 2016	(r303378)
+++ head/sys/conf/files.amd64	Wed Jul 27 09:27:08 2016	(r303379)
@@ -270,10 +270,10 @@ dev/hyperv/utilities/hv_kvp.c				optiona
 dev/hyperv/utilities/hv_shutdown.c			optional	hyperv
 dev/hyperv/utilities/hv_timesync.c			optional	hyperv
 dev/hyperv/utilities/hv_util.c				optional	hyperv
-dev/hyperv/vmbus/hv_ring_buffer.c			optional	hyperv
 dev/hyperv/vmbus/hyperv.c				optional	hyperv
 dev/hyperv/vmbus/hyperv_busdma.c			optional	hyperv
 dev/hyperv/vmbus/vmbus.c				optional	hyperv
+dev/hyperv/vmbus/vmbus_br.c				optional	hyperv
 dev/hyperv/vmbus/vmbus_chan.c				optional	hyperv
 dev/hyperv/vmbus/vmbus_et.c				optional	hyperv
 dev/hyperv/vmbus/vmbus_if.m				optional	hyperv

Modified: head/sys/conf/files.i386
==============================================================================
--- head/sys/conf/files.i386	Wed Jul 27 09:26:46 2016	(r303378)
+++ head/sys/conf/files.i386	Wed Jul 27 09:27:08 2016	(r303379)
@@ -246,10 +246,10 @@ dev/hyperv/utilities/hv_kvp.c				optiona
 dev/hyperv/utilities/hv_shutdown.c			optional	hyperv
 dev/hyperv/utilities/hv_timesync.c			optional	hyperv
 dev/hyperv/utilities/hv_util.c				optional	hyperv
-dev/hyperv/vmbus/hv_ring_buffer.c			optional	hyperv
 dev/hyperv/vmbus/hyperv.c				optional	hyperv
 dev/hyperv/vmbus/hyperv_busdma.c			optional	hyperv
 dev/hyperv/vmbus/vmbus.c				optional	hyperv
+dev/hyperv/vmbus/vmbus_br.c				optional	hyperv
 dev/hyperv/vmbus/vmbus_chan.c				optional	hyperv
 dev/hyperv/vmbus/vmbus_et.c				optional	hyperv
 dev/hyperv/vmbus/vmbus_if.m				optional	hyperv

Copied: head/sys/dev/hyperv/vmbus/vmbus_br.c (from r303378, head/sys/dev/hyperv/vmbus/hv_ring_buffer.c)
==============================================================================
--- /dev/null	00:00:00 1970	(empty, because file is newly added)
+++ head/sys/dev/hyperv/vmbus/vmbus_br.c	Wed Jul 27 09:27:08 2016	(r303379, copy of r303378, head/sys/dev/hyperv/vmbus/hv_ring_buffer.c)
@@ -0,0 +1,414 @@
+/*-
+ * Copyright (c) 2009-2012,2016 Microsoft Corp.
+ * Copyright (c) 2012 NetApp Inc.
+ * Copyright (c) 2012 Citrix Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice unmodified, this list of conditions, and the following
+ *    disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/param.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
+#include <sys/sysctl.h>
+
+#include <dev/hyperv/vmbus/vmbus_reg.h>
+#include <dev/hyperv/vmbus/vmbus_brvar.h>
+
+/* Amount of space available for write */
+#define	VMBUS_BR_WAVAIL(r, w, z)	\
+	(((w) >= (r)) ? ((z) - ((w) - (r))) : ((r) - (w)))
+
+/* Increase bufing index */
+#define VMBUS_BR_IDXINC(idx, inc, sz)	(((idx) + (inc)) % (sz))
+
+static int
+vmbus_br_sysctl_state(SYSCTL_HANDLER_ARGS)
+{
+	const struct vmbus_br *br = arg1;
+	uint32_t rindex, windex, imask, ravail, wavail;
+	char state[256];
+
+	rindex = br->vbr_rindex;
+	windex = br->vbr_windex;
+	imask = br->vbr_imask;
+	wavail = VMBUS_BR_WAVAIL(rindex, windex, br->vbr_dsize);
+	ravail = br->vbr_dsize - wavail;
+
+	snprintf(state, sizeof(state),
+	    "rindex:%u windex:%u imask:%u ravail:%u wavail:%u",
+	    rindex, windex, imask, ravail, wavail);
+	return sysctl_handle_string(oidp, state, sizeof(state), req);
+}
+
+/*
+ * Binary bufring states.
+ */
+static int
+vmbus_br_sysctl_state_bin(SYSCTL_HANDLER_ARGS)
+{
+#define BR_STATE_RIDX	0
+#define BR_STATE_WIDX	1
+#define BR_STATE_IMSK	2
+#define BR_STATE_RSPC	3
+#define BR_STATE_WSPC	4
+#define BR_STATE_MAX	5
+
+	const struct vmbus_br *br = arg1;
+	uint32_t rindex, windex, wavail, state[BR_STATE_MAX];
+
+	rindex = br->vbr_rindex;
+	windex = br->vbr_windex;
+	wavail = VMBUS_BR_WAVAIL(rindex, windex, br->vbr_dsize);
+
+	state[BR_STATE_RIDX] = rindex;
+	state[BR_STATE_WIDX] = windex;
+	state[BR_STATE_IMSK] = br->vbr_imask;
+	state[BR_STATE_WSPC] = wavail;
+	state[BR_STATE_RSPC] = br->vbr_dsize - wavail;
+
+	return sysctl_handle_opaque(oidp, state, sizeof(state), req);
+}
+
+void
+vmbus_br_sysctl_create(struct sysctl_ctx_list *ctx, struct sysctl_oid *br_tree,
+    struct vmbus_br *br, const char *name)
+{
+	struct sysctl_oid *tree;
+	char desc[64];
+
+	tree = SYSCTL_ADD_NODE(ctx, SYSCTL_CHILDREN(br_tree), OID_AUTO,
+	    name, CTLFLAG_RD | CTLFLAG_MPSAFE, 0, "");
+	if (tree == NULL)
+		return;
+
+	snprintf(desc, sizeof(desc), "%s state", name);
+	SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO, "state",
+	    CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
+	    br, 0, vmbus_br_sysctl_state, "A", desc);
+
+	snprintf(desc, sizeof(desc), "%s binary state", name);
+	SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO, "state_bin",
+	    CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE,
+	    br, 0, vmbus_br_sysctl_state_bin, "IU", desc);
+}
+
+void
+vmbus_rxbr_intr_mask(struct vmbus_rxbr *rbr)
+{
+	rbr->rxbr_imask = 1;
+	mb();
+}
+
+static __inline uint32_t
+vmbus_rxbr_avail(const struct vmbus_rxbr *rbr)
+{
+	uint32_t rindex, windex;
+
+	/* Get snapshot */
+	rindex = rbr->rxbr_rindex;
+	windex = rbr->rxbr_windex;
+
+	return (rbr->rxbr_dsize -
+	    VMBUS_BR_WAVAIL(rindex, windex, rbr->rxbr_dsize));
+}
+
+uint32_t
+vmbus_rxbr_intr_unmask(struct vmbus_rxbr *rbr)
+{
+	rbr->rxbr_imask = 0;
+	mb();
+
+	/*
+	 * Now check to see if the ring buffer is still empty.
+	 * If it is not, we raced and we need to process new
+	 * incoming channel packets.
+	 */
+	return vmbus_rxbr_avail(rbr);
+}
+
+static void
+vmbus_br_setup(struct vmbus_br *br, void *buf, int blen)
+{
+	br->vbr = buf;
+	br->vbr_dsize = blen - sizeof(struct vmbus_bufring);
+}
+
+void
+vmbus_rxbr_init(struct vmbus_rxbr *rbr)
+{
+	mtx_init(&rbr->rxbr_lock, "vmbus_rxbr", NULL, MTX_SPIN);
+}
+
+void
+vmbus_rxbr_deinit(struct vmbus_rxbr *rbr)
+{
+	mtx_destroy(&rbr->rxbr_lock);
+}
+
+void
+vmbus_rxbr_setup(struct vmbus_rxbr *rbr, void *buf, int blen)
+{
+	vmbus_br_setup(&rbr->rxbr, buf, blen);
+}
+
+void
+vmbus_txbr_init(struct vmbus_txbr *tbr)
+{
+	mtx_init(&tbr->txbr_lock, "vmbus_txbr", NULL, MTX_SPIN);
+}
+
+void
+vmbus_txbr_deinit(struct vmbus_txbr *tbr)
+{
+	mtx_destroy(&tbr->txbr_lock);
+}
+
+void
+vmbus_txbr_setup(struct vmbus_txbr *tbr, void *buf, int blen)
+{
+	vmbus_br_setup(&tbr->txbr, buf, blen);
+}
+
+/*
+ * When we write to the ring buffer, check if the host needs to be
+ * signaled.
+ *
+ * The contract:
+ * - The host guarantees that while it is draining the TX bufring,
+ *   it will set the br_imask to indicate it does not need to be
+ *   interrupted when new data are added.
+ * - The host guarantees that it will completely drain the TX bufring
+ *   before exiting the read loop.  Further, once the TX bufring is
+ *   empty, it will clear the br_imask and re-check to see if new
+ *   data have arrived.
+ */
+static __inline boolean_t
+vmbus_txbr_need_signal(const struct vmbus_txbr *tbr, uint32_t old_windex)
+{
+	mb();
+	if (tbr->txbr_imask)
+		return (FALSE);
+
+	/* XXX only compiler fence is needed */
+	/* Read memory barrier */
+	rmb();
+
+	/*
+	 * This is the only case we need to signal when the
+	 * ring transitions from being empty to non-empty.
+	 */
+	if (old_windex == tbr->txbr_rindex)
+		return (TRUE);
+
+	return (FALSE);
+}
+
+static __inline uint32_t
+vmbus_txbr_avail(const struct vmbus_txbr *tbr)
+{
+	uint32_t rindex, windex;
+
+	/* Get snapshot */
+	rindex = tbr->txbr_rindex;
+	windex = tbr->txbr_windex;
+
+	return VMBUS_BR_WAVAIL(rindex, windex, tbr->txbr_dsize);
+}
+
+static __inline uint32_t
+vmbus_txbr_copyto(const struct vmbus_txbr *tbr, uint32_t windex,
+    const void *src0, uint32_t cplen)
+{
+	const uint8_t *src = src0;
+	uint8_t *br_data = tbr->txbr_data;
+	uint32_t br_dsize = tbr->txbr_dsize;
+
+	if (cplen > br_dsize - windex) {
+		uint32_t fraglen = br_dsize - windex;
+
+		/* Wrap-around detected */
+		memcpy(br_data + windex, src, fraglen);
+		memcpy(br_data, src + fraglen, cplen - fraglen);
+	} else {
+		memcpy(br_data + windex, src, cplen);
+	}
+	return VMBUS_BR_IDXINC(windex, cplen, br_dsize);
+}
+
+/*
+ * Write scattered channel packet to TX bufring.
+ *
+ * The offset of this channel packet is written as a 64bits value
+ * immediately after this channel packet.
+ */
+int
+vmbus_txbr_write(struct vmbus_txbr *tbr, const struct iovec iov[], int iovlen,
+    boolean_t *need_sig)
+{
+	uint32_t old_windex, windex, total;
+	uint64_t save_windex;
+	int i;
+
+	total = 0;
+	for (i = 0; i < iovlen; i++)
+		total += iov[i].iov_len;
+	total += sizeof(save_windex);
+
+	mtx_lock_spin(&tbr->txbr_lock);
+
+	/*
+	 * NOTE:
+	 * If this write is going to make br_windex same as br_rindex,
+	 * i.e. the available space for write is same as the write size,
+	 * we can't do it then, since br_windex == br_rindex means that
+	 * the bufring is empty.
+	 */
+	if (vmbus_txbr_avail(tbr) <= total) {
+		mtx_unlock_spin(&tbr->txbr_lock);
+		return (EAGAIN);
+	}
+
+	/* Save br_windex for later use */
+	old_windex = tbr->txbr_windex;
+
+	/*
+	 * Copy the scattered channel packet to the TX bufring.
+	 */
+	windex = old_windex;
+	for (i = 0; i < iovlen; i++) {
+		windex = vmbus_txbr_copyto(tbr, windex,
+		    iov[i].iov_base, iov[i].iov_len);
+	}
+
+	/*
+	 * Set the offset of the current channel packet.
+	 */
+	save_windex = ((uint64_t)old_windex) << 32;
+	windex = vmbus_txbr_copyto(tbr, windex, &save_windex,
+	    sizeof(save_windex));
+
+	/*
+	 * XXX only compiler fence is needed.
+	 * Full memory barrier before upding the write index. 
+	 */
+	mb();
+
+	/*
+	 * Update the write index _after_ the channel packet
+	 * is copied.
+	 */
+	tbr->txbr_windex = windex;
+
+	mtx_unlock_spin(&tbr->txbr_lock);
+
+	*need_sig = vmbus_txbr_need_signal(tbr, old_windex);
+
+	return (0);
+}
+
+static __inline uint32_t
+vmbus_rxbr_copyfrom(const struct vmbus_rxbr *rbr, uint32_t rindex,
+    void *dst0, int cplen)
+{
+	uint8_t *dst = dst0;
+	const uint8_t *br_data = rbr->rxbr_data;
+	uint32_t br_dsize = rbr->rxbr_dsize;
+
+	if (cplen > br_dsize - rindex) {
+		uint32_t fraglen = br_dsize - rindex;
+
+		/* Wrap-around detected. */
+		memcpy(dst, br_data + rindex, fraglen);
+		memcpy(dst + fraglen, br_data, cplen - fraglen);
+	} else {
+		memcpy(dst, br_data + rindex, cplen);
+	}
+	return VMBUS_BR_IDXINC(rindex, cplen, br_dsize);
+}
+
+int
+vmbus_rxbr_peek(struct vmbus_rxbr *rbr, void *data, int dlen)
+{
+	mtx_lock_spin(&rbr->rxbr_lock);
+
+	/*
+	 * The requested data and the 64bits channel packet
+	 * offset should be there at least.
+	 */
+	if (vmbus_rxbr_avail(rbr) < dlen + sizeof(uint64_t)) {
+		mtx_unlock_spin(&rbr->rxbr_lock);
+		return (EAGAIN);
+	}
+	vmbus_rxbr_copyfrom(rbr, rbr->rxbr_rindex, data, dlen);
+
+	mtx_unlock_spin(&rbr->rxbr_lock);
+
+	return (0);
+}
+
+/*
+ * NOTE:
+ * We assume (dlen + skip) == sizeof(channel packet).
+ */
+int
+vmbus_rxbr_read(struct vmbus_rxbr *rbr, void *data, int dlen, uint32_t skip)
+{
+	uint32_t rindex, br_dsize = rbr->rxbr_dsize;
+
+	KASSERT(dlen + skip > 0, ("invalid dlen %d, offset %u", dlen, skip));
+
+	mtx_lock_spin(&rbr->rxbr_lock);
+
+	if (vmbus_rxbr_avail(rbr) < dlen + skip + sizeof(uint64_t)) {
+		mtx_unlock_spin(&rbr->rxbr_lock);
+		return (EAGAIN);
+	}
+
+	/*
+	 * Copy channel packet from RX bufring.
+	 */
+	rindex = VMBUS_BR_IDXINC(rbr->rxbr_rindex, skip, br_dsize);
+	rindex = vmbus_rxbr_copyfrom(rbr, rindex, data, dlen);
+
+	/*
+	 * Discard this channel packet's 64bits offset, which is useless to us.
+	 */
+	rindex = VMBUS_BR_IDXINC(rindex, sizeof(uint64_t), br_dsize);
+
+	/*
+	 * XXX only compiler fence is needed.
+	 * Make sure all reads are done before we update the read index since
+	 * the writer may start writing to the read area once the read index
+	 * is updated.
+	 */
+	wmb();
+
+	/*
+	 * Update the read index _after_ the channel packet is fetched.
+	 */
+	rbr->rxbr_rindex = rindex;
+
+	mtx_unlock_spin(&rbr->rxbr_lock);
+
+	return (0);
+}

Modified: head/sys/modules/hyperv/vmbus/Makefile
==============================================================================
--- head/sys/modules/hyperv/vmbus/Makefile	Wed Jul 27 09:26:46 2016	(r303378)
+++ head/sys/modules/hyperv/vmbus/Makefile	Wed Jul 27 09:27:08 2016	(r303379)
@@ -4,11 +4,11 @@
 	${.CURDIR}/../../../dev/hyperv/vmbus/${MACHINE_CPUARCH}
 
 KMOD=	hv_vmbus
-SRCS=	hv_ring_buffer.c \
-	hyperv.c \
+SRCS=	hyperv.c \
 	hyperv_busdma.c \
 	hyperv_machdep.c \
 	vmbus.c \
+	vmbus_br.c \
 	vmbus_chan.c \
 	vmbus_et.c
 SRCS+=	acpi_if.h bus_if.h device_if.h opt_acpi.h vmbus_if.h



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