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Date: Sun, 28 Feb 2016 23:58:05 +0530
From: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
To: outreachy-kernel@googlegroups.com
Subject: [PATCH] staging: fsl-mc: bus: Eliminate double function call
Message-ID: <20160228182805.GA30160@Karyakshetra>
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User-Agent: Mutt/1.5.23 (2014-03-12)

A call to irq_find_matching_host was already made and the result
has been stored in mc_msi_domain. mc_msi_domain is again reassigned
using the same function call which is redundant.

irq_find_matching_host returns/locates a domain for a given fwnode.
The domain is identified using device node and bus_token(if several
domains have same device node but different purposes they can be
distinguished using bus-specific token).
http://www.bricktou.com/include/linux/irqdomain_irq_find_matching_host_en.html

Also, of_property_read_bool finds and reads a boolean from a property
device node from which the property value is to be read. It doesn't
alter the device node.
http://lists.infradead.org/pipermail/linux-arm-kernel/2012-February/083698.html

Since, both  the function calls have the same device node and bus_token,
the return values shall be the same. Hence, the second call has been
removed.

This was done using Coccinelle:

@r@
idexpression *x;
identifier f;
position p1,p2;
@@

x@p1 = f(...)
... when != x
(
x@p2 = f(...)
)

@script:python@
p1 << r.p1;
p2 << r.p2;
@@

if (p1[0].line == p2[0].line):
  cocci.include_match(False)

@@
idexpression *x;
identifier f;
position r.p1,r.p2;
@@

*x@p1 = f(...)
...
*x@p2 = f(...)

Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
---
 drivers/staging/fsl-mc/bus/irq-gic-v3-its-fsl-mc-msi.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/staging/fsl-mc/bus/irq-gic-v3-its-fsl-mc-msi.c b/drivers/staging/fsl-mc/bus/irq-gic-v3-its-fsl-mc-msi.c
index 4e8e822..720e2b0 100644
--- a/drivers/staging/fsl-mc/bus/irq-gic-v3-its-fsl-mc-msi.c
+++ b/drivers/staging/fsl-mc/bus/irq-gic-v3-its-fsl-mc-msi.c
@@ -118,8 +118,6 @@ void its_fsl_mc_msi_cleanup(void)
 		if (!of_property_read_bool(np, "msi-controller"))
 			continue;

-		mc_msi_domain = irq_find_matching_host(np,
-						       DOMAIN_BUS_FSL_MC_MSI);
 		if (mc_msi_domain &&
 		    mc_msi_domain->host_data == &its_fsl_mc_msi_domain_info)
 			irq_domain_remove(mc_msi_domain);
--
2.1.4