Revert r271504. A new patch to solve this issue will be made.

Suggested by:	adrian @

11 files changed, 34 insertions, 193 deletions

diff --git a/sys/dev/oce/oce_if.c b/sys/dev/oce/oce_if.c
index 68985b8..af57491 100644
--- a/sys/dev/oce/oce_if.c
+++ b/sys/dev/oce/oce_if.c
@@ -1731,10 +1731,7 @@ oce_attach_ifp(POCE_SOFTC sc)
 	sc->ifp->if_baudrate = IF_Gbps(10);
 
 #if __FreeBSD_version >= 1000000
-	sc->ifp->if_hw_tsomax = IF_HW_TSOMAX_BUILD_VALUE(
-	    65535 - (ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN) /* bytes */,
-	    OCE_MAX_TX_ELEMENTS /* maximum frag count */,
-	    12 /* 4K frag size */);
+	sc->ifp->if_hw_tsomax = OCE_MAX_TSO_SIZE;
 #endif
 
 	ether_ifattach(sc->ifp, sc->macaddr.mac_addr);
diff --git a/sys/dev/oce/oce_if.h b/sys/dev/oce/oce_if.h
index bb78841..b6db402 100644
--- a/sys/dev/oce/oce_if.h
+++ b/sys/dev/oce/oce_if.h
@@ -152,6 +152,7 @@ extern int mp_ncpus;			/* system's total active cpu cores */
 #define OCE_MAX_TX_ELEMENTS		29
 #define OCE_MAX_TX_DESC			1024
 #define OCE_MAX_TX_SIZE			65535
+#define OCE_MAX_TSO_SIZE		(65535 - ETHER_HDR_LEN)
 #define OCE_MAX_RX_SIZE			4096
 #define OCE_MAX_RQ_POSTS		255
 #define OCE_DEFAULT_PROMISCUOUS		0
diff --git a/sys/dev/vmware/vmxnet3/if_vmx.c b/sys/dev/vmware/vmxnet3/if_vmx.c
index dd0eb6c..f3fde92 100644
--- a/sys/dev/vmware/vmxnet3/if_vmx.c
+++ b/sys/dev/vmware/vmxnet3/if_vmx.c
@@ -1722,11 +1722,7 @@ vmxnet3_setup_interface(struct vmxnet3_softc *sc)
 	ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
 	ifp->if_init = vmxnet3_init;
 	ifp->if_ioctl = vmxnet3_ioctl;
-
-	ifp->if_hw_tsomax = IF_HW_TSOMAX_BUILD_VALUE(
-	    65535 - sizeof(struct ether_vlan_header) /* bytes */,
-	    VMXNET3_TX_MAXSEGS /* maximum frag count */,
-	    VMXNET3_TX_MAXSEGSHIFT /* frag size */);
+	ifp->if_hw_tsomax = VMXNET3_TSO_MAXSIZE;
 
 #ifdef VMXNET3_LEGACY_TX
 	ifp->if_start = vmxnet3_start;
diff --git a/sys/dev/vmware/vmxnet3/if_vmxvar.h b/sys/dev/vmware/vmxnet3/if_vmxvar.h
index a6129f9..6c79721 100644
--- a/sys/dev/vmware/vmxnet3/if_vmxvar.h
+++ b/sys/dev/vmware/vmxnet3/if_vmxvar.h
@@ -277,13 +277,14 @@ struct vmxnet3_softc {
  */
 #define VMXNET3_TX_MAXSEGS		32
 #define VMXNET3_TX_MAXSIZE		(VMXNET3_TX_MAXSEGS * MCLBYTES)
+#define VMXNET3_TSO_MAXSIZE \
+    (VMXNET3_TX_MAXSIZE - sizeof(struct ether_vlan_header))
 
 /*
  * Maximum support Tx segments size. The length field in the
  * Tx descriptor is 14 bits.
  */
-#define VMXNET3_TX_MAXSEGSHIFT		14
-#define VMXNET3_TX_MAXSEGSIZE		(1 << VMXNET3_TX_MAXSEGSHIFT)
+#define VMXNET3_TX_MAXSEGSIZE		(1 << 14)
 
 /*
  * The maximum number of Rx segments we accept. When LRO is enabled,
diff --git a/sys/dev/xen/netfront/netfront.c b/sys/dev/xen/netfront/netfront.c
index 1fadee4..9ff872c 100644
--- a/sys/dev/xen/netfront/netfront.c
+++ b/sys/dev/xen/netfront/netfront.c
@@ -134,6 +134,7 @@ static const int MODPARM_rx_flip = 0;
  * to mirror the Linux MAX_SKB_FRAGS constant.
  */
 #define	MAX_TX_REQ_FRAGS (65536 / PAGE_SIZE + 2)
+#define	NF_TSO_MAXBURST ((IP_MAXPACKET / PAGE_SIZE) * MCLBYTES)
 
 #define RX_COPY_THRESHOLD 256
 
@@ -2101,10 +2102,7 @@ create_netdev(device_t dev)
 	
     	ifp->if_hwassist = XN_CSUM_FEATURES;
     	ifp->if_capabilities = IFCAP_HWCSUM;
-	ifp->if_hw_tsomax = IF_HW_TSOMAX_BUILD_VALUE(
-	    65535 - (ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN) /* bytes */,
-	    MAX_TX_REQ_FRAGS /* maximum frag count */,
-	    PAGE_SHIFT /* PAGE_SIZE frag size */);
+	ifp->if_hw_tsomax = NF_TSO_MAXBURST;
 	
     	ether_ifattach(ifp, np->mac);
     	callout_init(&np->xn_stat_ch, CALLOUT_MPSAFE);
diff --git a/sys/net/if.c b/sys/net/if.c
index 5e9b776..017af33 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -423,52 +423,6 @@ if_grow(void)
 }
 
 /*
- * Compute the least common value of two "if_hw_tsomax" values:
- */
-u_int
-if_hw_tsomax_common(u_int a, u_int b)
-{
-	u_int a_bytes = IF_HW_TSOMAX_GET_BYTES(a);
-	u_int a_frag_count = IF_HW_TSOMAX_GET_FRAG_COUNT(a);
-	u_int a_frag_size = IF_HW_TSOMAX_GET_FRAG_SIZE(a);
-	u_int b_bytes = IF_HW_TSOMAX_GET_BYTES(b);
-	u_int b_frag_count = IF_HW_TSOMAX_GET_FRAG_COUNT(b);
-	u_int b_frag_size = IF_HW_TSOMAX_GET_FRAG_SIZE(b);
-
-	return (IF_HW_TSOMAX_BUILD_VALUE(min(a_bytes, b_bytes),
-	    min(a_frag_count, b_frag_count),
-	    min(a_frag_size, b_frag_size)));
-}
-
-/*
- * Range check the "if_hw_tsomax" value:
- */
-u_int
-if_hw_tsomax_range_check(u_int a)
-{
-	u_int a_bytes = IF_HW_TSOMAX_GET_BYTES(a);
-	u_int a_frag_count = IF_HW_TSOMAX_GET_FRAG_COUNT(a);
-	u_int a_frag_size = IF_HW_TSOMAX_GET_FRAG_SIZE(a);
-
-	/* round down to nearest 4 bytes */
-	a_bytes &= 0xFFFC;
-
-	/* use default, if zero */
-	if (a_bytes == 0)
-		a_bytes = IF_HW_TSOMAX_DEFAULT_BYTES;
-
-	/* use default, if zero */
-	if (a_frag_count == 0)
-		a_frag_count = IF_HW_TSOMAX_DEFAULT_FRAG_COUNT;
-
-	/* use default, if zero */
-	if (a_frag_size == 0)
-		a_frag_size = IF_HW_TSOMAX_DEFAULT_FRAG_SIZE;
-
-	return (IF_HW_TSOMAX_BUILD_VALUE(a_bytes, a_frag_count, a_frag_size));
-}
-
-/*
  * Allocate a struct ifnet and an index for an interface.  A layer 2
  * common structure will also be allocated if an allocation routine is
  * registered for the passed type.
@@ -491,7 +445,6 @@ if_alloc(u_char type)
 	ifp->if_index = idx;
 	ifp->if_type = type;
 	ifp->if_alloctype = type;
-	ifp->if_hw_tsomax = IF_HW_TSOMAX_DEFAULT_VALUE();
 	if (if_com_alloc[type] != NULL) {
 		ifp->if_l2com = if_com_alloc[type](type, ifp);
 		if (ifp->if_l2com == NULL) {
@@ -704,9 +657,16 @@ if_attach_internal(struct ifnet *ifp, int vmove)
 		TAILQ_INSERT_HEAD(&ifp->if_addrhead, ifa, ifa_link);
 		/* Reliably crash if used uninitialized. */
 		ifp->if_broadcastaddr = NULL;
-		/* range check TSO value */
-		ifp->if_hw_tsomax =
-		    if_hw_tsomax_range_check(ifp->if_hw_tsomax);
+
+#if defined(INET) || defined(INET6)
+		/* Initialize to max value. */
+		if (ifp->if_hw_tsomax == 0)
+			ifp->if_hw_tsomax = min(IP_MAXPACKET, 32 * MCLBYTES -
+			    (ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN));
+		KASSERT(ifp->if_hw_tsomax <= IP_MAXPACKET &&
+		    ifp->if_hw_tsomax >= IP_MAXPACKET / 8,
+		    ("%s: tsomax outside of range", __func__));
+#endif
 	}
 #ifdef VIMAGE
 	else {
diff --git a/sys/net/if_lagg.c b/sys/net/if_lagg.c
index e7cfb3c..8d53526 100644
--- a/sys/net/if_lagg.c
+++ b/sys/net/if_lagg.c
@@ -445,7 +445,11 @@ lagg_capabilities(struct lagg_softc *sc)
 	struct lagg_port *lp;
 	int cap = ~0, ena = ~0;
 	u_long hwa = ~0UL;
-	u_int hw_tsomax = IF_HW_TSOMAX_DEFAULT_VALUE();
+#if defined(INET) || defined(INET6)
+	u_int hw_tsomax = IP_MAXPACKET;	/* Initialize to the maximum value. */
+#else
+	u_int hw_tsomax = ~0;	/* if_hw_tsomax is only for INET/INET6, but.. */
+#endif
 
 	LAGG_WLOCK_ASSERT(sc);
 
@@ -454,9 +458,10 @@ lagg_capabilities(struct lagg_softc *sc)
 		cap &= lp->lp_ifp->if_capabilities;
 		ena &= lp->lp_ifp->if_capenable;
 		hwa &= lp->lp_ifp->if_hwassist;
-		/* Set to the common value of the lagg ports. */
-		hw_tsomax = if_hw_tsomax_common(hw_tsomax,
-		    lp->lp_ifp->if_hw_tsomax);
+		/* Set to the minimum value of the lagg ports. */
+		if (lp->lp_ifp->if_hw_tsomax < hw_tsomax &&
+		    lp->lp_ifp->if_hw_tsomax > 0)
+			hw_tsomax = lp->lp_ifp->if_hw_tsomax;
 	}
 	cap = (cap == ~0 ? 0 : cap);
 	ena = (ena == ~0 ? 0 : ena);
diff --git a/sys/net/if_var.h b/sys/net/if_var.h
index af83713..09f41b8 100644
--- a/sys/net/if_var.h
+++ b/sys/net/if_var.h
@@ -120,43 +120,6 @@ typedef int (*if_transmit_fn_t)(if_t, struct mbuf *);
 typedef	uint64_t (*if_get_counter_t)(if_t, ifnet_counter);
 
 /*
- * Macros defining how to decode the "if_hw_tsomax" field:
- */
-#define	IF_HW_TSOMAX_GET_BYTES(x)		\
-    ((uint16_t)(x))	/* 32..65535 */
-
-#define	IF_HW_TSOMAX_GET_FRAG_COUNT(x)		\
-    ((uint8_t)((x) >> 16))	/* 1..255 */
-
-#define	IF_HW_TSOMAX_GET_FRAG_SIZE(x)		\
-    ((uint8_t)((x) >> 24))	/* 12..16 */
-
-/*
- * The following macro defines how to build the "if_hw_tsomax"
- * field. The "bytes" field has unit 1 bytes and declares the maximum
- * number of bytes which can be transferred by a single transmit
- * offload, TSO, job. The "bytes" field is rounded down to the neares
- * 4 bytes to avoid having the hardware do unaligned memory
- * accesses. The "frag_count" field has unit 1 fragment and declares
- * the maximum number of fragments a TSO job can contain. The
- * "frag_size" field has unit logarithm in base 2 of the actual value
- * in bytes and declares the maximum size of a fragment.
- */
-#define	IF_HW_TSOMAX_BUILD_VALUE(bytes, frag_count, frag_size)	\
-    (((bytes) & 0xFFFC) | (((frag_count) & 0xFF) << 16) |	\
-    (((frag_size) & 0xFF) << 24))
-
-#define	IF_HW_TSOMAX_DEFAULT_BYTES (65536 - 4)
-#define	IF_HW_TSOMAX_DEFAULT_FRAG_COUNT 255
-#define	IF_HW_TSOMAX_DEFAULT_FRAG_SIZE 16
-
-#define	IF_HW_TSOMAX_DEFAULT_VALUE()		\
-    IF_HW_TSOMAX_BUILD_VALUE(			\
-    IF_HW_TSOMAX_DEFAULT_BYTES,			\
-    IF_HW_TSOMAX_DEFAULT_FRAG_COUNT,		\
-    IF_HW_TSOMAX_DEFAULT_FRAG_SIZE)
-
-/*
  * Structure defining a network interface.
  *
  * Size ILP32:  592 (approx)
@@ -259,7 +222,8 @@ struct ifnet {
 	if_get_counter_t if_get_counter; /* get counter values */
 
 	/* Stuff that's only temporary and doesn't belong here. */
-	u_int	if_hw_tsomax;		/* TSO burst length limits.
+	u_int	if_hw_tsomax;		/* tso burst length limit, the minimum
+					 * is (IP_MAXPACKET / 8).
 					 * XXXAO: Have to find a better place
 					 * for it eventually. */
 	/*
@@ -644,10 +608,6 @@ void if_setioctlfn(if_t ifp, int (*)(if_t, u_long, caddr_t));
 void if_setstartfn(if_t ifp, void (*)(if_t));
 void if_settransmitfn(if_t ifp, if_transmit_fn_t);
 void if_setqflushfn(if_t ifp, if_qflush_fn_t);
-
-/* "if_hw_tsomax" related functions */
-u_int if_hw_tsomax_common(u_int, u_int);
-u_int if_hw_tsomax_range_check(u_int);
  
 /* Revisit the below. These are inline functions originally */
 int drbr_inuse_drv(if_t ifp, struct buf_ring *br);
diff --git a/sys/net/if_vlan.c b/sys/net/if_vlan.c
index b7ccb61..5a5e712 100644
--- a/sys/net/if_vlan.c
+++ b/sys/net/if_vlan.c
@@ -1557,8 +1557,8 @@ vlan_capabilities(struct ifvlan *ifv)
 	 * propagate the hardware-assisted flag. TSO on VLANs
 	 * does not necessarily require hardware VLAN tagging.
 	 */
-	ifp->if_hw_tsomax = if_hw_tsomax_common(ifp->if_hw_tsomax,
-	    p->if_hw_tsomax);
+	if (p->if_hw_tsomax > 0)
+		ifp->if_hw_tsomax = p->if_hw_tsomax;
 	if (p->if_capabilities & IFCAP_VLAN_HWTSO)
 		ifp->if_capabilities |= p->if_capabilities & IFCAP_TSO;
 	if (p->if_capenable & IFCAP_VLAN_HWTSO) {
diff --git a/sys/netinet/tcp_output.c b/sys/netinet/tcp_output.c
index 5537416..12d8e75 100644
--- a/sys/netinet/tcp_output.c
+++ b/sys/netinet/tcp_output.c
@@ -52,7 +52,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/sysctl.h>
 
 #include <net/if.h>
-#include <net/if_var.h>
 #include <net/route.h>
 #include <net/vnet.h>
 
@@ -768,88 +767,18 @@ send:
 		flags &= ~TH_FIN;
 
 		if (tso) {
-			u_int if_hw_tsomax_bytes;
-			u_int if_hw_tsomax_frag_count;
-			u_int if_hw_tsomax_frag_size;
-			struct mbuf *mb;
-			u_int moff;
-			int max_len;
-
-			/* extract TSO information */
-			if_hw_tsomax_bytes =
-			    IF_HW_TSOMAX_GET_BYTES(tp->t_tsomax);
-			if_hw_tsomax_frag_count =
-			    IF_HW_TSOMAX_GET_FRAG_COUNT(tp->t_tsomax);
-			if_hw_tsomax_frag_size =
-			    IF_HW_TSOMAX_GET_FRAG_SIZE(tp->t_tsomax);
-
-			/* compute maximum TSO length */
-			max_len = (if_hw_tsomax_bytes - hdrlen);
-
-			/* clamp maximum length value */
-			if (max_len > IP_MAXPACKET)
-				max_len = IP_MAXPACKET;
-			else if (max_len < 0)
-				max_len = 0;
-
-			/* get smallest length */
-			if (len > (u_int)max_len) {
-				if (max_len != 0)
-					sendalot = 1;
-				len = (u_int)max_len;
-			}
-
 			KASSERT(ipoptlen == 0,
 			    ("%s: TSO can't do IP options", __func__));
 
-			max_len = 0;
-			mb = sbsndptr(&so->so_snd, off, len, &moff);
-
-			/* now make sure the number of fragments fit too */
-			while (mb != NULL && (u_int)max_len < len) {
-				u_int cur_length;
-				u_int cur_frags;
-
-				/*
-				 * Get length of mbuf fragment and how
-				 * many hardware frags, rounded up, it
-				 * would use:
-				 */
-				cur_length = (mb->m_len - moff);
-				cur_frags = (cur_length +
-				    (1 << if_hw_tsomax_frag_size) - 1) >>
-				    if_hw_tsomax_frag_size;
-
-				/* Handle special case: Zero Length Mbuf */
-				if (cur_frags == 0)
-					cur_frags = 1;
-
-				/*
-				 * Check if the fragment limit will be
-				 * reached or exceeded:
-				 */
-				if (cur_frags >= if_hw_tsomax_frag_count) {
-					max_len += min(cur_length,
-					    if_hw_tsomax_frag_count <<
-					    if_hw_tsomax_frag_size);
-					break;
-				}
-				max_len += cur_length;
-				if_hw_tsomax_frag_count -= cur_frags;
-				moff = 0;
-				mb = mb->m_next;
-			}
-
 			/*
 			 * Limit a burst to t_tsomax minus IP,
 			 * TCP and options length to keep ip->ip_len
 			 * from overflowing or exceeding the maximum
 			 * length allowed by the network interface.
 			 */
-			if (len > (u_int)max_len) {
-				if (max_len != 0)
-					sendalot = 1;
-				len = (u_int)max_len;
+			if (len > tp->t_tsomax - hdrlen) {
+				len = tp->t_tsomax - hdrlen;
+				sendalot = 1;
 			}
 
 			/*
diff --git a/sys/ofed/drivers/net/mlx4/en_netdev.c b/sys/ofed/drivers/net/mlx4/en_netdev.c
index a8eb5c8..d8b015b 100644
--- a/sys/ofed/drivers/net/mlx4/en_netdev.c
+++ b/sys/ofed/drivers/net/mlx4/en_netdev.c
@@ -673,12 +673,6 @@ int mlx4_en_do_start_port(struct net_device *dev)
 	else
 		priv->rx_csum = 0;
 
-	/* set TSO limits so that we don't have to drop TX packets */
-	dev->if_hw_tsomax = IF_HW_TSOMAX_BUILD_VALUE(
-	    65535 - sizeof(struct ether_vlan_header) /* bytes */,
-	    16 /* maximum frag count */,
-	    16 /* can do up to 4GByte */);
-
 	err = mlx4_wol_read(priv->mdev->dev, &config, priv->port);
 	if (err) {
 		en_err(priv, "Failed to get WoL info, unable to modify\n");