[PATCH] [54/275] rapidio: fix hang on RapidIO doorbell queue full condition

[Andi Kleen]

2.6.35-longterm review patch.  If anyone has any objections, please let me know.

------------------
From: Thomas Taranowski <tom@xxxxxxxxxxxxxxx>

commit 12a4dc43911785f51a596f771ae0701b18d436f1 upstream.

In fsl_rio_dbell_handler() the code currently simply acknowledges the QFI
queue full interrupt, but does nothing to resolve the queue full
condition.  Instead, it jumps to the end of the isr.  When a queue full
condition occurs, the isr is then re-entered immediately and continually,
forever.

The fix is to just fall through and read out current doorbell entries.

Signed-off-by: Thomas Taranowski <tom@xxxxxxxxxxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Alexandre Bounine <alexandre.bounine@xxxxxxx>
Cc: Kumar Gala <galak@xxxxxxxxxxxxxxxxxxx>
Cc: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx>
Cc: Li Yang <leoli@xxxxxxxxxxxxx>
Cc: Thomas Moll <thomas.moll@xxxxxxxxx>
Cc: Micha Nelissen <micha@xxxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Grant Likely <grant.likely@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 arch/powerpc/sysdev/fsl_rio.c |    1 -
 1 file changed, 1 deletion(-)

Index: linux-2.6.35.y/arch/powerpc/sysdev/fsl_rio.c
===================================================================
--- linux-2.6.35.y.orig/arch/powerpc/sysdev/fsl_rio.c	2011-03-29 22:51:48.062493371 -0700
+++ linux-2.6.35.y/arch/powerpc/sysdev/fsl_rio.c	2011-03-29 23:02:59.287318406 -0700
@@ -952,7 +952,6 @@
 	if (dsr & DOORBELL_DSR_QFI) {
 		pr_info("RIO: doorbell queue full\n");
 		out_be32(&priv->msg_regs->dsr, DOORBELL_DSR_QFI);
-		goto out;
 	}
 
 	/* XXX Need to check/dispatch until queue empty */
--
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