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RDMA/iw_cxgb4: atomic find and reference for listening endpoints

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Add get_ep_from_stid() which will atomically find and reference the
endpoint struct if found. This avoids touch-after-free races between
threads destroying listening endpoints and the CPL processing thread
processing an incoming PASS_ACCEPT_REQ CPL.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Hariprasad S 2016-05-06 22:18:07 +05:30 committed by Doug Ledford
parent e8667a9b35
commit f86fac79af
1 changed files with 28 additions and 8 deletions
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36
drivers/infiniband/hw/cxgb4/cm.c
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@ -342,6 +342,23 @@ static struct c4iw_ep *get_ep_from_tid(struct c4iw_dev *dev, unsigned int tid)
return ep;
}
/*
* Atomically lookup the ep ptr given the stid and grab a reference on the ep.
*/
static struct c4iw_listen_ep *get_ep_from_stid(struct c4iw_dev *dev,
unsigned int stid)
{
struct c4iw_listen_ep *ep;
unsigned long flags;
spin_lock_irqsave(&dev->lock, flags);
ep = idr_find(&dev->stid_idr, stid);
if (ep)
c4iw_get_ep(&ep->com);
spin_unlock_irqrestore(&dev->lock, flags);
return ep;
}
void _c4iw_free_ep(struct kref *kref)
{
struct c4iw_ep *ep;
@ -2306,9 +2323,8 @@ fail:
static int pass_open_rpl(struct c4iw_dev *dev, struct sk_buff *skb)
{
struct cpl_pass_open_rpl *rpl = cplhdr(skb);
struct tid_info *t = dev->rdev.lldi.tids;
unsigned int stid = GET_TID(rpl);
struct c4iw_listen_ep *ep = lookup_stid(t, stid);
struct c4iw_listen_ep *ep = get_ep_from_stid(dev, stid);
if (!ep) {
PDBG("%s stid %d lookup failure!\n", __func__, stid);
@ -2317,7 +2333,7 @@ static int pass_open_rpl(struct c4iw_dev *dev, struct sk_buff *skb)
PDBG("%s ep %p status %d error %d\n", __func__, ep,
rpl->status, status2errno(rpl->status));
c4iw_wake_up(&ep->com.wr_wait, status2errno(rpl->status));
c4iw_put_ep(&ep->com);
out:
return 0;
}
@ -2325,12 +2341,12 @@ out:
static int close_listsrv_rpl(struct c4iw_dev *dev, struct sk_buff *skb)
{
struct cpl_close_listsvr_rpl *rpl = cplhdr(skb);
struct tid_info *t = dev->rdev.lldi.tids;
unsigned int stid = GET_TID(rpl);
struct c4iw_listen_ep *ep = lookup_stid(t, stid);
struct c4iw_listen_ep *ep = get_ep_from_stid(dev, stid);
PDBG("%s ep %p\n", __func__, ep);
c4iw_wake_up(&ep->com.wr_wait, status2errno(rpl->status));
c4iw_put_ep(&ep->com);
return 0;
}
@ -2490,7 +2506,7 @@ static int pass_accept_req(struct c4iw_dev *dev, struct sk_buff *skb)
unsigned short hdrs;
u8 tos = PASS_OPEN_TOS_G(ntohl(req->tos_stid));
parent_ep = lookup_stid(t, stid);
parent_ep = (struct c4iw_ep *)get_ep_from_stid(dev, stid);
if (!parent_ep) {
PDBG("%s connect request on invalid stid %d\n", __func__, stid);
goto reject;
@ -2618,6 +2634,8 @@ static int pass_accept_req(struct c4iw_dev *dev, struct sk_buff *skb)
goto out;
reject:
reject_cr(dev, hwtid, skb);
if (parent_ep)
c4iw_put_ep(&parent_ep->com);
out:
return 0;
}
@ -3868,7 +3886,7 @@ static int rx_pkt(struct c4iw_dev *dev, struct sk_buff *skb)
struct cpl_pass_accept_req *req = (void *)(rss + 1);
struct l2t_entry *e;
struct dst_entry *dst;
struct c4iw_ep *lep;
struct c4iw_ep *lep = NULL;
u16 window;
struct port_info *pi;
struct net_device *pdev;
@ -3893,7 +3911,7 @@ static int rx_pkt(struct c4iw_dev *dev, struct sk_buff *skb)
*/
stid = (__force int) cpu_to_be32((__force u32) rss->hash_val);
lep = (struct c4iw_ep *)lookup_stid(dev->rdev.lldi.tids, stid);
lep = (struct c4iw_ep *)get_ep_from_stid(dev, stid);
if (!lep) {
PDBG("%s connect request on invalid stid %d\n", __func__, stid);
goto reject;
@ -3994,6 +4012,8 @@ static int rx_pkt(struct c4iw_dev *dev, struct sk_buff *skb)
free_dst:
dst_release(dst);
reject:
if (lep)
c4iw_put_ep(&lep->com);
return 0;
}