[MIPS] SMTC: Fix recursion in instant IPI replay code.
local_irq_restore -> raw_local_irq_restore -> irq_restore_epilog ->
smtc_ipi_replay -> smtc_ipi_dq -> spin_unlock_irqrestore ->
_spin_unlock_irqrestore -> local_irq_restore
The recursion does abort when there is no more IPI queued for a CPU, so
this isn't usually fatal which is why we got away with this for so long
until this was discovered by code inspection.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/include/asm-mips/smtc_ipi.h b/include/asm-mips/smtc_ipi.h
index 360ea6d..a52a4a7 100644
--- a/include/asm-mips/smtc_ipi.h
+++ b/include/asm-mips/smtc_ipi.h
@@ -65,12 +65,10 @@
spin_unlock_irqrestore(&q->lock, flags);
}
-static inline struct smtc_ipi *smtc_ipi_dq(struct smtc_ipi_q *q)
+static inline struct smtc_ipi *__smtc_ipi_dq(struct smtc_ipi_q *q)
{
struct smtc_ipi *p;
- long flags;
- spin_lock_irqsave(&q->lock, flags);
if (q->head == NULL)
p = NULL;
else {
@@ -81,7 +79,19 @@
if (q->head == NULL)
q->tail = NULL;
}
+
+ return p;
+}
+
+static inline struct smtc_ipi *smtc_ipi_dq(struct smtc_ipi_q *q)
+{
+ unsigned long flags;
+ struct smtc_ipi *p;
+
+ spin_lock_irqsave(&q->lock, flags);
+ p = __smtc_ipi_dq(q);
spin_unlock_irqrestore(&q->lock, flags);
+
return p;
}