linux-kernel - [PATCH v4 6/7] xen-pciback: short-circuit read path used for merging write values

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Message-Id: <577CC87702000078000FB800@prv-mh.provo.novell.com>
Date:	Wed, 06 Jul 2016 00:59:35 -0600
From:	"Jan Beulich" <JBeulich@...e.com>
To:	"David Vrabel" <david.vrabel@...rix.com>,
	"Boris Ostrovsky" <boris.ostrovsky@...cle.com>,
	"Juergen Gross" <JGross@...e.com>
Cc:	"xen-devel" <xen-devel@...ts.xenproject.org>,
	<linux-kernel@...r.kernel.org>
Subject: [PATCH v4 6/7] xen-pciback: short-circuit read path used for
 merging write values

There's no point calling xen_pcibk_config_read() here - all it'll do is
return whatever conf_space_read() returns for the field which was found
here (and which would be found there again). Also there's no point
clearing tmp_val before the call.

Signed-off-by: Jan Beulich <jbeulich@...e.com>
---
 drivers/xen/xen-pciback/conf_space.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

--- 4.7-rc6-xen-pciback.orig/drivers/xen/xen-pciback/conf_space.c
+++ 4.7-rc6-xen-pciback/drivers/xen/xen-pciback/conf_space.c
@@ -230,10 +230,8 @@ int xen_pcibk_config_write(struct pci_de
 		field_end = OFFSET(cfg_entry) + field->size;
 
 		 if (req_end > field_start && field_end > req_start) {
-			tmp_val = 0;
-
-			err = xen_pcibk_config_read(dev, field_start,
-						  field->size, &tmp_val);
+			err = conf_space_read(dev, cfg_entry, field_start,
+					      &tmp_val);
 			if (err)
 				break;