[Xen-devel] [PATCH for-4.6 v2 7/8] python/xc: reinstate original implementation of next_bdf

[Wei Liu <wei.liu2@xxxxxxxxxx>]

I missed the fact that next_bdf is used to parsed user supplied
strings when reviewing. The user supplied string is a NULL-terminated
string separated by comma. User can supply several PCI devices in that
string. There is, however, no delimiter for different devices, hence
we can't change the syntax of that string.

This patch reinstate the original implementation of next_bdf to
preserve the original syntax. The last argument for xc_assign_device
is always 0.

Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
Cc: Tiejun Chen <tiejun.chen@xxxxxxxxx>

Tiejun, are you actually using this python binding? I don't think we
have in tree user.

If nobody is using it, I propose we remove this binding in next
release.

I don't have live example of that string. My analysis is based on
reverse-engineering of original code.
---
 tools/python/xen/lowlevel/xc/xc.c | 30 ++++++++++--------------------
 1 file changed, 10 insertions(+), 20 deletions(-)

diff --git a/tools/python/xen/lowlevel/xc/xc.c 
b/tools/python/xen/lowlevel/xc/xc.c
index c8380d1..2c36eb2 100644
--- a/tools/python/xen/lowlevel/xc/xc.c
+++ b/tools/python/xen/lowlevel/xc/xc.c
@@ -592,8 +592,7 @@ static int token_value(char *token)
     return strtol(token, NULL, 16);
 }
 
-static int next_bdf(char **str, int *seg, int *bus, int *dev, int *func,
-                    int *flag)
+static int next_bdf(char **str, int *seg, int *bus, int *dev, int *func)
 {
     char *token;
 
@@ -608,17 +607,8 @@ static int next_bdf(char **str, int *seg, int *bus, int 
*dev, int *func,
     *dev  = token_value(token);
     token = strchr(token, ',') + 1;
     *func  = token_value(token);
-    token = strchr(token, ',') + 1;
-    if ( token ) {
-        *flag = token_value(token);
-        *str = token + 1;
-    }
-    else
-    {
-        /* O means we take "strict" as our default policy. */
-        *flag = 0;
-        *str = NULL;
-    }
+    token = strchr(token, ',');
+    *str = token ? token + 1 : NULL;
 
     return 1;
 }
@@ -630,14 +620,14 @@ static PyObject *pyxc_test_assign_device(XcObject *self,
     uint32_t dom;
     char *pci_str;
     int32_t sbdf = 0;
-    int seg, bus, dev, func, flag;
+    int seg, bus, dev, func;
 
     static char *kwd_list[] = { "domid", "pci", NULL };
     if ( !PyArg_ParseTupleAndKeywords(args, kwds, "is", kwd_list,
                                       &dom, &pci_str) )
         return NULL;
 
-    while ( next_bdf(&pci_str, &seg, &bus, &dev, &func, &flag) )
+    while ( next_bdf(&pci_str, &seg, &bus, &dev, &func) )
     {
         sbdf = seg << 16;
         sbdf |= (bus & 0xff) << 8;
@@ -663,21 +653,21 @@ static PyObject *pyxc_assign_device(XcObject *self,
     uint32_t dom;
     char *pci_str;
     int32_t sbdf = 0;
-    int seg, bus, dev, func, flag;
+    int seg, bus, dev, func;
 
     static char *kwd_list[] = { "domid", "pci", NULL };
     if ( !PyArg_ParseTupleAndKeywords(args, kwds, "is", kwd_list,
                                       &dom, &pci_str) )
         return NULL;
 
-    while ( next_bdf(&pci_str, &seg, &bus, &dev, &func, &flag) )
+    while ( next_bdf(&pci_str, &seg, &bus, &dev, &func) )
     {
         sbdf = seg << 16;
         sbdf |= (bus & 0xff) << 8;
         sbdf |= (dev & 0x1f) << 3;
         sbdf |= (func & 0x7);
 
-        if ( xc_assign_device(self->xc_handle, dom, sbdf, flag) != 0 )
+        if ( xc_assign_device(self->xc_handle, dom, sbdf, 0) != 0 )
         {
             if (errno == ENOSYS)
                 sbdf = -1;
@@ -696,14 +686,14 @@ static PyObject *pyxc_deassign_device(XcObject *self,
     uint32_t dom;
     char *pci_str;
     int32_t sbdf = 0;
-    int seg, bus, dev, func, flag;
+    int seg, bus, dev, func;
 
     static char *kwd_list[] = { "domid", "pci", NULL };
     if ( !PyArg_ParseTupleAndKeywords(args, kwds, "is", kwd_list,
                                       &dom, &pci_str) )
         return NULL;
 
-    while ( next_bdf(&pci_str, &seg, &bus, &dev, &func, &flag) )
+    while ( next_bdf(&pci_str, &seg, &bus, &dev, &func) )
     {
         sbdf = seg << 16;
         sbdf |= (bus & 0xff) << 8;
-- 
2.1.4


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