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IB/qib: Fix potential deadlock with link down interrupt

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There is a possibility of a deadlock due to the way locks are
acquired and released in qib_set_uevent_bits(). The function
qib_set_uevent_bits() is called in process context and it uses
spin_lock() and spin_unlock().  This same lock is acquired/released
in interrupt context which can lead to a deadlock when running on
the same cpu.

The fix is to replace spin_lock() and spin_unlock() with
spin_lock_irqsave() and spin_unlock_irqrestore() respectively in
qib_set_uevent_bits().

Signed-off-by: Mike Marciniszyn <mike.marciniszyn@qlogic.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
This commit is contained in:
Ram Vepa 2011-05-27 13:41:55 +00:00 committed by Roland Dreier
parent 2df4f7579d
commit 4356d0b64b
1 changed files with 3 additions and 2 deletions
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5
drivers/infiniband/hw/qib/qib_file_ops.c
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@ -1905,8 +1905,9 @@ int qib_set_uevent_bits(struct qib_pportdata *ppd, const int evtbit)
struct qib_ctxtdata *rcd;
unsigned ctxt;
int ret = 0;
unsigned long flags;
spin_lock(&ppd->dd->uctxt_lock);
spin_lock_irqsave(&ppd->dd->uctxt_lock, flags);
for (ctxt = ppd->dd->first_user_ctxt; ctxt < ppd->dd->cfgctxts;
ctxt++) {
rcd = ppd->dd->rcd[ctxt];
@ -1925,7 +1926,7 @@ int qib_set_uevent_bits(struct qib_pportdata *ppd, const int evtbit)
ret = 1;
break;
}
spin_unlock(&ppd->dd->uctxt_lock);
spin_unlock_irqrestore(&ppd->dd->uctxt_lock, flags);
return ret;
}