[Xen-devel] [PATCH] xen/pciif: Clarify what values go in op->err and op->result.

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

The earlier comment says that errno values go in op->err.
However all implementations (NetBSD, Linux) of the most
common operations use XEN_PCI_ERR_* instead of -EXX values.

The exception is the xen-pciback in Linux code when doing
XEN_PCI_OP_enable_msix can stash the -EXX in op->result
and in op->err.

As such lets clarify what '->err' and '->result' are
suppose to contain.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
 xen/include/public/io/pciif.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/xen/include/public/io/pciif.h b/xen/include/public/io/pciif.h
index a4ba13c..535963a 100644
--- a/xen/include/public/io/pciif.h
+++ b/xen/include/public/io/pciif.h
@@ -71,7 +71,7 @@ struct xen_pci_op {
     /* IN: what action to perform: XEN_PCI_OP_* */
     uint32_t cmd;
 
-    /* OUT: will contain an error number (if any) from errno.h */
+    /* OUT: will contain an XEN_PCI_ERR_* value. */
     int32_t err;
 
     /* IN: which device to touch */
@@ -83,7 +83,9 @@ struct xen_pci_op {
     int32_t offset;
     int32_t size;
 
-    /* IN/OUT: Contains the result after a READ or the value to WRITE */
+    /* IN/OUT: Contains the result after a READ or the value to WRITE.
+     * If the err does not have XEN_PCI_ERR_success, depending on
+     *  XEN_PCI_OP_* might have the errno value. */
     uint32_t value;
     /* IN: Contains extra infor for this operation */
     uint32_t info;
-- 
2.1.0


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel