[IB] Fix MAD layer DMA mappings to avoid touching data buffer once mapped

The MAD layer was violating the DMA API by touching data buffers used
for sends after the DMA mapping was done.  This causes problems on
non-cache-coherent architectures, because the device doing DMA won't
see updates to the payload buffers that exist only in the CPU cache.

Fix this by having all MAD consumers use ib_create_send_mad() to
allocate their send buffers, and moving the DMA mapping into the MAD
layer so it can be done just before calling send (and after any
modifications of the send buffer by the MAD layer).

Tested on a non-cache-coherent PowerPC 440SPe system.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 76 insertions, 217 deletions

diff --git a/drivers/infiniband/core/agent.c b/drivers/infiniband/core/agent.c
index 5ac86f566dc0..0c3c6952faae 100644
--- a/drivers/infiniband/core/agent.c
+++ b/drivers/infiniband/core/agent.c
@@ -37,58 +37,41 @@
  * $Id: agent.c 1389 2004-12-27 22:56:47Z roland $
  */
 
-#include <linux/dma-mapping.h>
-
-#include <asm/bug.h>
+#include "agent.h"
+#include "smi.h"
 
-#include <rdma/ib_smi.h>
+#define SPFX "ib_agent: "
 
-#include "smi.h"
-#include "agent_priv.h"
-#include "mad_priv.h"
-#include "agent.h"
+struct ib_agent_port_private {
+	struct list_head port_list;
+	struct ib_mad_agent *agent[2];
+};
 
-spinlock_t ib_agent_port_list_lock;
+static DEFINE_SPINLOCK(ib_agent_port_list_lock);
 static LIST_HEAD(ib_agent_port_list);
 
-/*
- * Caller must hold ib_agent_port_list_lock
- */
-static inline struct ib_agent_port_private *
-__ib_get_agent_port(struct ib_device *device, int port_num,
-		    struct ib_mad_agent *mad_agent)
+static struct ib_agent_port_private *
+__ib_get_agent_port(struct ib_device *device, int port_num)
 {
 	struct ib_agent_port_private *entry;
 
-	BUG_ON(!(!!device ^ !!mad_agent));  /* Exactly one MUST be (!NULL) */
-
-	if (device) {
-		list_for_each_entry(entry, &ib_agent_port_list, port_list) {
-			if (entry->smp_agent->device == device &&
-			    entry->port_num == port_num)
-				return entry;
-		}
-	} else {
-		list_for_each_entry(entry, &ib_agent_port_list, port_list) {
-			if ((entry->smp_agent == mad_agent) ||
-			    (entry->perf_mgmt_agent == mad_agent))
-				return entry;
-		}
+	list_for_each_entry(entry, &ib_agent_port_list, port_list) {
+		if (entry->agent[0]->device == device &&
+		    entry->agent[0]->port_num == port_num)
+			return entry;
 	}
 	return NULL;
 }
 
-static inline struct ib_agent_port_private *
-ib_get_agent_port(struct ib_device *device, int port_num,
-		  struct ib_mad_agent *mad_agent)
+static struct ib_agent_port_private *
+ib_get_agent_port(struct ib_device *device, int port_num)
 {
 	struct ib_agent_port_private *entry;
 	unsigned long flags;
 
 	spin_lock_irqsave(&ib_agent_port_list_lock, flags);
-	entry = __ib_get_agent_port(device, port_num, mad_agent);
+	entry = __ib_get_agent_port(device, port_num);
 	spin_unlock_irqrestore(&ib_agent_port_list_lock, flags);
-
 	return entry;
 }
 
@@ -100,192 +83,76 @@ int smi_check_local_dr_smp(struct ib_smp *smp,
 
 	if (smp->mgmt_class != IB_MGMT_CLASS_SUBN_DIRECTED_ROUTE)
 		return 1;
-	port_priv = ib_get_agent_port(device, port_num, NULL);
+
+	port_priv = ib_get_agent_port(device, port_num);
 	if (!port_priv) {
 		printk(KERN_DEBUG SPFX "smi_check_local_dr_smp %s port %d "
-		       "not open\n",
-		       device->name, port_num);
+		       "not open\n", device->name, port_num);
 		return 1;
 	}
 
-	return smi_check_local_smp(port_priv->smp_agent, smp);
+	return smi_check_local_smp(port_priv->agent[0], smp);
 }
 
-static int agent_mad_send(struct ib_mad_agent *mad_agent,
-			  struct ib_agent_port_private *port_priv,
-			  struct ib_mad_private *mad_priv,
-			  struct ib_grh *grh,
-			  struct ib_wc *wc)
+int agent_send_response(struct ib_mad *mad, struct ib_grh *grh,
+			struct ib_wc *wc, struct ib_device *device,
+			int port_num, int qpn)
 {
-	struct ib_agent_send_wr *agent_send_wr;
-	struct ib_sge gather_list;
-	struct ib_send_wr send_wr;
-	struct ib_send_wr *bad_send_wr;
-	struct ib_ah_attr ah_attr;
-	unsigned long flags;
-	int ret = 1;
-
-	agent_send_wr = kmalloc(sizeof(*agent_send_wr), GFP_KERNEL);
-	if (!agent_send_wr)
-		goto out;
-	agent_send_wr->mad = mad_priv;
-
-	gather_list.addr = dma_map_single(mad_agent->device->dma_device,
-					  &mad_priv->mad,
-					  sizeof(mad_priv->mad),
-					  DMA_TO_DEVICE);
-	gather_list.length = sizeof(mad_priv->mad);
-	gather_list.lkey = mad_agent->mr->lkey;
-
-	send_wr.next = NULL;
-	send_wr.opcode = IB_WR_SEND;
-	send_wr.sg_list = &gather_list;
-	send_wr.num_sge = 1;
-	send_wr.wr.ud.remote_qpn = wc->src_qp; /* DQPN */
-	send_wr.wr.ud.timeout_ms = 0;
-	send_wr.send_flags = IB_SEND_SIGNALED | IB_SEND_SOLICITED;
+	struct ib_agent_port_private *port_priv;
+	struct ib_mad_agent *agent;
+	struct ib_mad_send_buf *send_buf;
+	struct ib_ah *ah;
+	int ret;
 
-	ah_attr.dlid = wc->slid;
-	ah_attr.port_num = mad_agent->port_num;
-	ah_attr.src_path_bits = wc->dlid_path_bits;
-	ah_attr.sl = wc->sl;
-	ah_attr.static_rate = 0;
-	ah_attr.ah_flags = 0; /* No GRH */
-	if (mad_priv->mad.mad.mad_hdr.mgmt_class == IB_MGMT_CLASS_PERF_MGMT) {
-		if (wc->wc_flags & IB_WC_GRH) {
-			ah_attr.ah_flags = IB_AH_GRH;
-			/* Should sgid be looked up ? */
-			ah_attr.grh.sgid_index = 0;
-			ah_attr.grh.hop_limit = grh->hop_limit;
-			ah_attr.grh.flow_label = be32_to_cpu(
-				grh->version_tclass_flow)  & 0xfffff;
-			ah_attr.grh.traffic_class = (be32_to_cpu(
-				grh->version_tclass_flow) >> 20) & 0xff;
-			memcpy(ah_attr.grh.dgid.raw,
-			       grh->sgid.raw,
-			       sizeof(ah_attr.grh.dgid));
-		}
+	port_priv = ib_get_agent_port(device, port_num);
+	if (!port_priv) {
+		printk(KERN_ERR SPFX "Unable to find port agent\n");
+		return -ENODEV;
 	}
 
-	agent_send_wr->ah = ib_create_ah(mad_agent->qp->pd, &ah_attr);
-	if (IS_ERR(agent_send_wr->ah)) {
-		printk(KERN_ERR SPFX "No memory for address handle\n");
-		kfree(agent_send_wr);
-		goto out;
+	agent = port_priv->agent[qpn];
+	ah = ib_create_ah_from_wc(agent->qp->pd, wc, grh, port_num);
+	if (IS_ERR(ah)) {
+		ret = PTR_ERR(ah);
+		printk(KERN_ERR SPFX "ib_create_ah_from_wc error:%d\n", ret);
+		return ret;
 	}
 
-	send_wr.wr.ud.ah = agent_send_wr->ah;
-	if (mad_priv->mad.mad.mad_hdr.mgmt_class == IB_MGMT_CLASS_PERF_MGMT) {
-		send_wr.wr.ud.pkey_index = wc->pkey_index;
-		send_wr.wr.ud.remote_qkey = IB_QP1_QKEY;
-	} else { 	/* for SMPs */
-		send_wr.wr.ud.pkey_index = 0;
-		send_wr.wr.ud.remote_qkey = 0;
+	send_buf = ib_create_send_mad(agent, wc->src_qp, wc->pkey_index, 0,
+				      IB_MGMT_MAD_HDR, IB_MGMT_MAD_DATA,
+				      GFP_KERNEL);
+	if (IS_ERR(send_buf)) {
+		ret = PTR_ERR(send_buf);
+		printk(KERN_ERR SPFX "ib_create_send_mad error:%d\n", ret);
+		goto err1;
 	}
-	send_wr.wr.ud.mad_hdr = &mad_priv->mad.mad.mad_hdr;
-	send_wr.wr_id = (unsigned long)agent_send_wr;
 
-	pci_unmap_addr_set(agent_send_wr, mapping, gather_list.addr);
-
-	/* Send */
-	spin_lock_irqsave(&port_priv->send_list_lock, flags);
-	if (ib_post_send_mad(mad_agent, &send_wr, &bad_send_wr)) {
-		spin_unlock_irqrestore(&port_priv->send_list_lock, flags);
-		dma_unmap_single(mad_agent->device->dma_device,
-				 pci_unmap_addr(agent_send_wr, mapping),
-				 sizeof(mad_priv->mad),
-				 DMA_TO_DEVICE);
-		ib_destroy_ah(agent_send_wr->ah);
-		kfree(agent_send_wr);
-	} else {
-		list_add_tail(&agent_send_wr->send_list,
-			      &port_priv->send_posted_list);
-		spin_unlock_irqrestore(&port_priv->send_list_lock, flags);
-		ret = 0;
+	memcpy(send_buf->mad, mad, sizeof *mad);
+	send_buf->ah = ah;
+	if ((ret = ib_post_send_mad(send_buf, NULL))) {
+		printk(KERN_ERR SPFX "ib_post_send_mad error:%d\n", ret);
+		goto err2;
 	}
-
-out:
+	return 0;
+err2:
+	ib_free_send_mad(send_buf);
+err1:
+	ib_destroy_ah(ah);
 	return ret;
 }
 
-int agent_send(struct ib_mad_private *mad,
-	       struct ib_grh *grh,
-	       struct ib_wc *wc,
-	       struct ib_device *device,
-	       int port_num)
-{
-	struct ib_agent_port_private *port_priv;
-	struct ib_mad_agent *mad_agent;
-
-	port_priv = ib_get_agent_port(device, port_num, NULL);
-	if (!port_priv) {
-		printk(KERN_DEBUG SPFX "agent_send %s port %d not open\n",
-		       device->name, port_num);
-		return 1;
-	}
-
-	/* Get mad agent based on mgmt_class in MAD */
-	switch (mad->mad.mad.mad_hdr.mgmt_class) {
-		case IB_MGMT_CLASS_SUBN_DIRECTED_ROUTE:
-		case IB_MGMT_CLASS_SUBN_LID_ROUTED:
-			mad_agent = port_priv->smp_agent;
-			break;
-		case IB_MGMT_CLASS_PERF_MGMT:
-			mad_agent = port_priv->perf_mgmt_agent;
-			break;
-		default:
-			return 1;
-	}
-
-	return agent_mad_send(mad_agent, port_priv, mad, grh, wc);
-}
-
 static void agent_send_handler(struct ib_mad_agent *mad_agent,
 			       struct ib_mad_send_wc *mad_send_wc)
 {
-	struct ib_agent_port_private	*port_priv;
-	struct ib_agent_send_wr		*agent_send_wr;
-	unsigned long			flags;
-
-	/* Find matching MAD agent */
-	port_priv = ib_get_agent_port(NULL, 0, mad_agent);
-	if (!port_priv) {
-		printk(KERN_ERR SPFX "agent_send_handler: no matching MAD "
-		       "agent %p\n", mad_agent);
-		return;
-	}
-
-	agent_send_wr = (struct ib_agent_send_wr *)(unsigned long)mad_send_wc->wr_id;
-	spin_lock_irqsave(&port_priv->send_list_lock, flags);
-	/* Remove completed send from posted send MAD list */
-	list_del(&agent_send_wr->send_list);
-	spin_unlock_irqrestore(&port_priv->send_list_lock, flags);
-
-	dma_unmap_single(mad_agent->device->dma_device,
-			 pci_unmap_addr(agent_send_wr, mapping),
-			 sizeof(agent_send_wr->mad->mad),
-			 DMA_TO_DEVICE);
-
-	ib_destroy_ah(agent_send_wr->ah);
-
-	/* Release allocated memory */
-	kmem_cache_free(ib_mad_cache, agent_send_wr->mad);
-	kfree(agent_send_wr);
+	ib_destroy_ah(mad_send_wc->send_buf->ah);
+	ib_free_send_mad(mad_send_wc->send_buf);
 }
 
 int ib_agent_port_open(struct ib_device *device, int port_num)
 {
-	int ret;
 	struct ib_agent_port_private *port_priv;
 	unsigned long flags;
-
-	/* First, check if port already open for SMI */
-	port_priv = ib_get_agent_port(device, port_num, NULL);
-	if (port_priv) {
-		printk(KERN_DEBUG SPFX "%s port %d already open\n",
-		       device->name, port_num);
-		return 0;
-	}
+	int ret;
 
 	/* Create new device info */
 	port_priv = kmalloc(sizeof *port_priv, GFP_KERNEL);
@@ -294,32 +161,25 @@ int ib_agent_port_open(struct ib_device *device, int port_num)
 		ret = -ENOMEM;
 		goto error1;
 	}
-
 	memset(port_priv, 0, sizeof *port_priv);
-	port_priv->port_num = port_num;
-	spin_lock_init(&port_priv->send_list_lock);
-	INIT_LIST_HEAD(&port_priv->send_posted_list);
 
-	/* Obtain send only MAD agent for SM class (SMI QP) */
-	port_priv->smp_agent = ib_register_mad_agent(device, port_num,
-						     IB_QPT_SMI,
-						     NULL, 0,
+	/* Obtain send only MAD agent for SMI QP */
+	port_priv->agent[0] = ib_register_mad_agent(device, port_num,
+						    IB_QPT_SMI, NULL, 0,
 						    &agent_send_handler,
-						     NULL, NULL);
-
-	if (IS_ERR(port_priv->smp_agent)) {
-		ret = PTR_ERR(port_priv->smp_agent);
+						    NULL, NULL);
+	if (IS_ERR(port_priv->agent[0])) {
+		ret = PTR_ERR(port_priv->agent[0]);
 		goto error2;
 	}
 
-	/* Obtain send only MAD agent for PerfMgmt class (GSI QP) */
-	port_priv->perf_mgmt_agent = ib_register_mad_agent(device, port_num,
-							   IB_QPT_GSI,
-							   NULL, 0,
-							  &agent_send_handler,
-							   NULL, NULL);
-	if (IS_ERR(port_priv->perf_mgmt_agent)) {
-		ret = PTR_ERR(port_priv->perf_mgmt_agent);
+	/* Obtain send only MAD agent for GSI QP */
+	port_priv->agent[1] = ib_register_mad_agent(device, port_num,
+						    IB_QPT_GSI, NULL, 0,
+						    &agent_send_handler,
+						    NULL, NULL);
+	if (IS_ERR(port_priv->agent[1])) {
+		ret = PTR_ERR(port_priv->agent[1]);
 		goto error3;
 	}
 
@@ -330,7 +190,7 @@ int ib_agent_port_open(struct ib_device *device, int port_num)
 	return 0;
 
 error3:
-	ib_unregister_mad_agent(port_priv->smp_agent);
+	ib_unregister_mad_agent(port_priv->agent[0]);
 error2:
 	kfree(port_priv);
 error1:
@@ -343,7 +203,7 @@ int ib_agent_port_close(struct ib_device *device, int port_num)
 	unsigned long flags;
 
 	spin_lock_irqsave(&ib_agent_port_list_lock, flags);
-	port_priv = __ib_get_agent_port(device, port_num, NULL);
+	port_priv = __ib_get_agent_port(device, port_num);
 	if (port_priv == NULL) {
 		spin_unlock_irqrestore(&ib_agent_port_list_lock, flags);
 		printk(KERN_ERR SPFX "Port %d not found\n", port_num);
@@ -352,9 +212,8 @@ int ib_agent_port_close(struct ib_device *device, int port_num)
 	list_del(&port_priv->port_list);
 	spin_unlock_irqrestore(&ib_agent_port_list_lock, flags);
 
-	ib_unregister_mad_agent(port_priv->perf_mgmt_agent);
-	ib_unregister_mad_agent(port_priv->smp_agent);
+	ib_unregister_mad_agent(port_priv->agent[1]);
+	ib_unregister_mad_agent(port_priv->agent[0]);
 	kfree(port_priv);
-
 	return 0;
 }