[ofa-general] Re: [PATCH] - [resend] Corrects a race in ipoib_cm_post_receive_nonsrq()
Roland Dreier
rdreier at cisco.com
Fri Jun 27 15:26:31 PDT 2008
I just added this patch to my tree, which I hope should fix this problem
without adding a huge stack space allocation (which might cause other
issues under load later). It's a little more complicated but I feel
better about fixing things this way.
Can you guys review/test this and let me know if it looks OK?
Thanks,
Roland
>From 93c47a64b0bf01b69e711698c3bc1b10deb1ca6f Mon Sep 17 00:00:00 2001
From: Roland Dreier <rolandd at cisco.com>
Date: Fri, 27 Jun 2008 15:24:15 -0700
Subject: [PATCH] IPoIB/cm: Fix racy use of receive WR/SGL in ipoib_cm_post_receive_nonsrq()
For devices that don't support SRQs, ipoib_cm_post_receive_nonsrq() is
called from both ipoib_cm_handle_rx_wc() and ipoib_cm_nonsrq_init_rx(),
and these two callers are not synchronized against each other.
However, ipoib_cm_post_receive_nonsrq() always reuses the same receive
work request and scatter list structures, so multiple callers can end
up stepping on each other, which leads to posting garbled work
requests.
Fix this by having the caller pass in the ib_recv_wr and ib_sge
structures to use, and allocating new local structures in
ipoib_cm_nonsrq_init_rx().
Based on a patch by Pradeep Satyanarayana <pradeep at us.ibm.com> and
David Wilder <dwilder at us.ibm.com>, with debugging help from Hoang-Nam
Nguyen <hnguyen at de.ibm.com>.
Signed-off-by: Roland Dreier <rolandd at cisco.com>
---
drivers/infiniband/ulp/ipoib/ipoib_cm.c | 63 +++++++++++++++++++++++--------
1 files changed, 47 insertions(+), 16 deletions(-)
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
index 6223fc3..37bf67b 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
@@ -111,18 +111,20 @@ static int ipoib_cm_post_receive_srq(struct net_device *dev, int id)
}
static int ipoib_cm_post_receive_nonsrq(struct net_device *dev,
- struct ipoib_cm_rx *rx, int id)
+ struct ipoib_cm_rx *rx,
+ struct ib_recv_wr *wr,
+ struct ib_sge *sge, int id)
{
struct ipoib_dev_priv *priv = netdev_priv(dev);
struct ib_recv_wr *bad_wr;
int i, ret;
- priv->cm.rx_wr.wr_id = id | IPOIB_OP_CM | IPOIB_OP_RECV;
+ wr->wr_id = id | IPOIB_OP_CM | IPOIB_OP_RECV;
for (i = 0; i < IPOIB_CM_RX_SG; ++i)
- priv->cm.rx_sge[i].addr = rx->rx_ring[id].mapping[i];
+ sge[i].addr = rx->rx_ring[id].mapping[i];
- ret = ib_post_recv(rx->qp, &priv->cm.rx_wr, &bad_wr);
+ ret = ib_post_recv(rx->qp, wr, &bad_wr);
if (unlikely(ret)) {
ipoib_warn(priv, "post recv failed for buf %d (%d)\n", id, ret);
ipoib_cm_dma_unmap_rx(priv, IPOIB_CM_RX_SG - 1,
@@ -320,10 +322,33 @@ static int ipoib_cm_modify_rx_qp(struct net_device *dev,
return 0;
}
+static void ipoib_cm_init_rx_wr(struct net_device *dev,
+ struct ib_recv_wr *wr,
+ struct ib_sge *sge)
+{
+ struct ipoib_dev_priv *priv = netdev_priv(dev);
+ int i;
+
+ for (i = 0; i < priv->cm.num_frags; ++i)
+ sge[i].lkey = priv->mr->lkey;
+
+ sge[0].length = IPOIB_CM_HEAD_SIZE;
+ for (i = 1; i < priv->cm.num_frags; ++i)
+ sge[i].length = PAGE_SIZE;
+
+ wr->next = NULL;
+ wr->sg_list = priv->cm.rx_sge;
+ wr->num_sge = priv->cm.num_frags;
+}
+
static int ipoib_cm_nonsrq_init_rx(struct net_device *dev, struct ib_cm_id *cm_id,
struct ipoib_cm_rx *rx)
{
struct ipoib_dev_priv *priv = netdev_priv(dev);
+ struct {
+ struct ib_recv_wr wr;
+ struct ib_sge sge[IPOIB_CM_RX_SG];
+ } *t;
int ret;
int i;
@@ -331,6 +356,14 @@ static int ipoib_cm_nonsrq_init_rx(struct net_device *dev, struct ib_cm_id *cm_i
if (!rx->rx_ring)
return -ENOMEM;
+ t = kmalloc(sizeof *t, GFP_KERNEL);
+ if (!t) {
+ ret = -ENOMEM;
+ goto err_free;
+ }
+
+ ipoib_cm_init_rx_wr(dev, &t->wr, t->sge);
+
spin_lock_irq(&priv->lock);
if (priv->cm.nonsrq_conn_qp >= ipoib_max_conn_qp) {
@@ -349,8 +382,8 @@ static int ipoib_cm_nonsrq_init_rx(struct net_device *dev, struct ib_cm_id *cm_i
ipoib_warn(priv, "failed to allocate receive buffer %d\n", i);
ret = -ENOMEM;
goto err_count;
- }
- ret = ipoib_cm_post_receive_nonsrq(dev, rx, i);
+ }
+ ret = ipoib_cm_post_receive_nonsrq(dev, rx, &t->wr, t->sge, i);
if (ret) {
ipoib_warn(priv, "ipoib_cm_post_receive_nonsrq "
"failed for buf %d\n", i);
@@ -361,6 +394,8 @@ static int ipoib_cm_nonsrq_init_rx(struct net_device *dev, struct ib_cm_id *cm_i
rx->recv_count = ipoib_recvq_size;
+ kfree(t);
+
return 0;
err_count:
@@ -369,6 +404,7 @@ err_count:
spin_unlock_irq(&priv->lock);
err_free:
+ kfree(t);
ipoib_cm_free_rx_ring(dev, rx->rx_ring);
return ret;
@@ -637,7 +673,10 @@ repost:
ipoib_warn(priv, "ipoib_cm_post_receive_srq failed "
"for buf %d\n", wr_id);
} else {
- if (unlikely(ipoib_cm_post_receive_nonsrq(dev, p, wr_id))) {
+ if (unlikely(ipoib_cm_post_receive_nonsrq(dev, p,
+ &priv->cm.rx_wr,
+ priv->cm.rx_sge,
+ wr_id))) {
--p->recv_count;
ipoib_warn(priv, "ipoib_cm_post_receive_nonsrq failed "
"for buf %d\n", wr_id);
@@ -1502,15 +1541,7 @@ int ipoib_cm_dev_init(struct net_device *dev)
priv->cm.num_frags = IPOIB_CM_RX_SG;
}
- for (i = 0; i < priv->cm.num_frags; ++i)
- priv->cm.rx_sge[i].lkey = priv->mr->lkey;
-
- priv->cm.rx_sge[0].length = IPOIB_CM_HEAD_SIZE;
- for (i = 1; i < priv->cm.num_frags; ++i)
- priv->cm.rx_sge[i].length = PAGE_SIZE;
- priv->cm.rx_wr.next = NULL;
- priv->cm.rx_wr.sg_list = priv->cm.rx_sge;
- priv->cm.rx_wr.num_sge = priv->cm.num_frags;
+ ipoib_cm_init_rx_wr(dev, &priv->cm.rx_wr, priv->cm.rx_sge);
if (ipoib_cm_has_srq(dev)) {
for (i = 0; i < ipoib_recvq_size; ++i) {
--
1.5.6
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