[Xen-changelog] [xen master] libxl: slightly refine pci-assignable-{add, remove} handling

[patchbot@xxxxxxx]

commit 6e1e3480c3878bac5d244925974a6852c47c809b
Author:     Jan Beulich <JBeulich@xxxxxxxx>
AuthorDate: Thu Sep 10 06:36:54 2015 -0600
Commit:     Ian Campbell <ian.campbell@xxxxxxxxxx>
CommitDate: Tue Sep 15 11:58:26 2015 +0100

    libxl: slightly refine pci-assignable-{add, remove} handling
    
    While it appears to be intentional for "xl pci-assignable-remove" to
    not re-bind the original driver by default (requires the -r option),
    permanently losing the information which driver was originally used
    seems bad. Make "add; remove; add; remove -r" re-bind the original
    driver by allowing "remove" to delete the information only upon
    successful re-bind.
    
    In the course of this I also noticed that binding information is lost
    when upon first "add" pciback isn't loaded yet, due to its presence not
    being checked for early enough. Adjust pciback_dev_is_assigned()
    accordingly, and properly distinguish "yes" and "error" returns in the
    "add" case (removing a redundant error message from the "remove" path
    for consistency).
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: George Dunlap <george.dunlap@xxxxxxxxxx>
    Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
 tools/libxl/libxl_pci.c |   30 ++++++++++++++++++++++++++----
 1 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/tools/libxl/libxl_pci.c b/tools/libxl/libxl_pci.c
index 1ebdce7..bb54426 100644
--- a/tools/libxl/libxl_pci.c
+++ b/tools/libxl/libxl_pci.c
@@ -543,6 +543,17 @@ static int pciback_dev_is_assigned(libxl__gc *gc, 
libxl_device_pci *pcidev)
     int rc;
     struct stat st;
 
+    if ( access(SYSFS_PCIBACK_DRIVER, F_OK) < 0 ) {
+        if ( errno == ENOENT ) {
+            LIBXL__LOG(ctx, LIBXL__LOG_ERROR,
+                       "Looks like pciback driver is not loaded");
+        } else {
+            LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR,
+                             "Can't access "SYSFS_PCIBACK_DRIVER);
+        }
+        return -1;
+    }
+
     spath = libxl__sprintf(gc, SYSFS_PCIBACK_DRIVER"/"PCI_BDF,
                            pcidev->domain, pcidev->bus,
                            pcidev->dev, pcidev->func);
@@ -658,6 +669,7 @@ static int libxl__device_pci_assignable_add(libxl__gc *gc,
     libxl_ctx *ctx = libxl__gc_owner(gc);
     unsigned dom, bus, dev, func;
     char *spath, *driver_path = NULL;
+    int rc;
     struct stat st;
 
     /* Local copy for convenience */
@@ -674,7 +686,11 @@ static int libxl__device_pci_assignable_add(libxl__gc *gc,
     }
 
     /* Check to see if it's already assigned to pciback */
-    if ( pciback_dev_is_assigned(gc, pcidev) ) {
+    rc = pciback_dev_is_assigned(gc, pcidev);
+    if ( rc < 0 ) {
+        return ERROR_FAIL;
+    }
+    if ( rc ) {
         LIBXL__LOG(ctx, LIBXL__LOG_WARNING, PCI_BDF" already assigned to 
pciback",
                    dom, bus, dev, func);
         return 0;
@@ -692,11 +708,18 @@ static int libxl__device_pci_assignable_add(libxl__gc *gc,
     if ( rebind ) {
         if ( driver_path ) {
             pci_assignable_driver_path_write(gc, pcidev, driver_path);
+        } else if ( (driver_path =
+                     pci_assignable_driver_path_read(gc, pcidev)) != NULL ) {
+            LIBXL__LOG(ctx, LIBXL__LOG_INFO,
+                       PCI_BDF" not bound to a driver, will be rebound to %s",
+                       dom, bus, dev, func, driver_path);
         } else {
             LIBXL__LOG(ctx, LIBXL__LOG_WARNING,
                        PCI_BDF" not bound to a driver, will not be rebound.",
                        dom, bus, dev, func);
         }
+    } else {
+        pci_assignable_driver_path_remove(gc, pcidev);
     }
 
     if ( pciback_dev_assign(gc, pcidev) ) {
@@ -717,7 +740,6 @@ static int libxl__device_pci_assignable_remove(libxl__gc 
*gc,
 
     /* Unbind from pciback */
     if ( (rc=pciback_dev_is_assigned(gc, pcidev)) < 0 ) {
-        LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "Checking if pciback was assigned");
         return ERROR_FAIL;
     } else if ( rc ) {
         pciback_dev_unassign(gc, pcidev);
@@ -741,9 +763,9 @@ static int libxl__device_pci_assignable_remove(libxl__gc 
*gc,
                                  "Couldn't bind device to %s", driver_path);
                 return -1;
             }
-        }
 
-        pci_assignable_driver_path_remove(gc, pcidev);
+            pci_assignable_driver_path_remove(gc, pcidev);
+        }
     } else {
         if ( rebind ) {
             LIBXL__LOG(ctx, LIBXL__LOG_WARNING,
--
generated by git-patchbot for /home/xen/git/xen.git#master

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