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RDMA/cxgb4: Serialize CQ event upcalls with CQ destruction 

A race exists where the application can be destroying the CQ concurrently
with a HW interrupt indicating a completion has been inserted into the CQ.
This can cause an event notification upcall to the application after the
CQ has been destroyed.

The solution is to serialize looking up the CQ in the IDR table and
referencing the CQ in c4iw_ev_handler() with removing the CQID from the
IDR table and blocking until the refcnt reaches 0 in c4iw_destroy_cq().

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
This commit is contained in:
Hariprasad S 2014-12-17 14:11:02 +05:30 committed by Roland Dreier
parent bfa76d4957
commit c62e689631
1 changed files with 8 additions and 1 deletions
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9
drivers/infiniband/hw/cxgb4/ev.c
View File

@ -225,13 +225,20 @@ int c4iw_ev_handler(struct c4iw_dev *dev, u32 qid)
struct c4iw_cq *chp;
unsigned long flag;
spin_lock_irqsave(&dev->lock, flag);
chp = get_chp(dev, qid);
if (chp) {
atomic_inc(&chp->refcnt);
spin_unlock_irqrestore(&dev->lock, flag);
t4_clear_cq_armed(&chp->cq);
spin_lock_irqsave(&chp->comp_handler_lock, flag);
(*chp->ibcq.comp_handler)(&chp->ibcq, chp->ibcq.cq_context);
spin_unlock_irqrestore(&chp->comp_handler_lock, flag);
} else
if (atomic_dec_and_test(&chp->refcnt))
wake_up(&chp->wait);
} else {
PDBG("%s unknown cqid 0x%x\n", __func__, qid);
spin_unlock_irqrestore(&dev->lock, flag);
}
return 0;
}