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@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

1 files changed, 2 insertions, 4 deletions

diff --git a/drivers/xen/xen-pciback/conf_space.c b/drivers/xen/xen-pciback/conf_space.c
index 6a25533da237..6855bf552126 100644
--- a/drivers/xen/xen-pciback/conf_space.c
+++ b/drivers/xen/xen-pciback/conf_space.c
@@ -230,10 +230,8 @@ int xen_pcibk_config_write(struct pci_dev *dev, int offset, int size, u32 value)
                 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;