xen/pcifront: move xenstore config scanning into sub-function

pcifront_try_connect() and pcifront_attach_devices() share a large
chunk of duplicated code for reading the config information from
Xenstore, which only differs regarding calling pcifront_rescan_root()
or pcifront_scan_root().

Put that code into a new sub-function. It is fine to always call
pcifront_rescan_root() from that common function, as it will fallback
to pcifront_scan_root() if the domain/bus combination isn't known
yet (and pcifront_scan_root() should never be called for an already
known domain/bus combination anyway). In order to avoid duplicate
messages for the fallback case move the check for domain/bus not known
to the beginning of pcifront_rescan_root().

While at it fix the error reporting in case the root-xx node had the
wrong format.

As the return value of pcifront_try_connect() and
pcifront_attach_devices() are not used anywhere make those functions
return void. As an additional bonus this removes the dubious return
of -EFAULT in case of an unexpected driver state.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jason Andryuk <jandryuk@gmail.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c
index 77e61b4..7378e2f 100644 (file)
--- a/drivers/pci/xen-pcifront.c
+++ b/drivers/pci/xen-pcifront.c
@@ -521,24 +521,14 @@ static int pcifront_rescan_root(struct pcifront_device *pdev,
        int err;
        struct pci_bus *b;
 
-#ifndef CONFIG_PCI_DOMAINS
-       if (domain != 0) {
-               dev_err(&pdev->xdev->dev,
-                       "PCI Root in non-zero PCI Domain! domain=%d\n", domain);
-               dev_err(&pdev->xdev->dev,
-                       "Please compile with CONFIG_PCI_DOMAINS\n");
-               return -EINVAL;
-       }
-#endif
-
-       dev_info(&pdev->xdev->dev, "Rescanning PCI Frontend Bus %04x:%02x\n",
-                domain, bus);
-
        b = pci_find_bus(domain, bus);
        if (!b)
                /* If the bus is unknown, create it. */
                return pcifront_scan_root(pdev, domain, bus);
 
+       dev_info(&pdev->xdev->dev, "Rescanning PCI Frontend Bus %04x:%02x\n",
+                domain, bus);
+
        err = pcifront_scan_bus(pdev, domain, bus, b);
 
        /* Claim resources before going "live" with our devices */
@@ -819,76 +809,73 @@ out:
        return err;
 }
 
-static int pcifront_try_connect(struct pcifront_device *pdev)
+static void pcifront_connect(struct pcifront_device *pdev)
 {
-       int err = -EFAULT;
+       int err;
        int i, num_roots, len;
        char str[64];
        unsigned int domain, bus;
 
-
-       /* Only connect once */
-       if (xenbus_read_driver_state(pdev->xdev->nodename) !=
-           XenbusStateInitialised)
-               goto out;
-
-       err = pcifront_connect_and_init_dma(pdev);
-       if (err && err != -EEXIST) {
-               xenbus_dev_fatal(pdev->xdev, err,
-                                "Error setting up PCI Frontend");
-               goto out;
-       }
-
        err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend,
                           "root_num", "%d", &num_roots);
        if (err == -ENOENT) {
                xenbus_dev_error(pdev->xdev, err,
                                 "No PCI Roots found, trying 0000:00");
-               err = pcifront_scan_root(pdev, 0, 0);
+               err = pcifront_rescan_root(pdev, 0, 0);
                if (err) {
                        xenbus_dev_fatal(pdev->xdev, err,
                                         "Error scanning PCI root 0000:00");
-                       goto out;
+                       return;
                }
                num_roots = 0;
        } else if (err != 1) {
-               if (err == 0)
-                       err = -EINVAL;
-               xenbus_dev_fatal(pdev->xdev, err,
+               xenbus_dev_fatal(pdev->xdev, err >= 0 ? -EINVAL : err,
                                 "Error reading number of PCI roots");
-               goto out;
+               return;
        }
 
        for (i = 0; i < num_roots; i++) {
                len = snprintf(str, sizeof(str), "root-%d", i);
-               if (unlikely(len >= (sizeof(str) - 1))) {
-                       err = -ENOMEM;
-                       goto out;
-               }
+               if (unlikely(len >= (sizeof(str) - 1)))
+                       return;
 
                err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
                                   "%x:%x", &domain, &bus);
                if (err != 2) {
-                       if (err >= 0)
-                               err = -EINVAL;
-                       xenbus_dev_fatal(pdev->xdev, err,
+                       xenbus_dev_fatal(pdev->xdev, err >= 0 ? -EINVAL : err,
                                         "Error reading PCI root %d", i);
-                       goto out;
+                       return;
                }
 
-               err = pcifront_scan_root(pdev, domain, bus);
+               err = pcifront_rescan_root(pdev, domain, bus);
                if (err) {
                        xenbus_dev_fatal(pdev->xdev, err,
                                         "Error scanning PCI root %04x:%02x",
                                         domain, bus);
-                       goto out;
+                       return;
                }
        }
 
-       err = xenbus_switch_state(pdev->xdev, XenbusStateConnected);
+       xenbus_switch_state(pdev->xdev, XenbusStateConnected);
+}
 
-out:
-       return err;
+static void pcifront_try_connect(struct pcifront_device *pdev)
+{
+       int err;
+
+       /* Only connect once */
+       if (xenbus_read_driver_state(pdev->xdev->nodename) !=
+           XenbusStateInitialised)
+               return;
+
+       err = pcifront_connect_and_init_dma(pdev);
+       if (err && err != -EEXIST) {
+               xenbus_dev_fatal(pdev->xdev, err,
+                                "Error setting up PCI Frontend");
+               return;
+       }
+
+       pcifront_connect(pdev);
 }
 
 static int pcifront_try_disconnect(struct pcifront_device *pdev)
@@ -914,67 +901,11 @@ out:
        return err;
 }
 
-static int pcifront_attach_devices(struct pcifront_device *pdev)
+static void pcifront_attach_devices(struct pcifront_device *pdev)
 {
-       int err = -EFAULT;
-       int i, num_roots, len;
-       unsigned int domain, bus;
-       char str[64];
-
-       if (xenbus_read_driver_state(pdev->xdev->nodename) !=
+       if (xenbus_read_driver_state(pdev->xdev->nodename) ==
            XenbusStateReconfiguring)
-               goto out;
-
-       err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend,
-                          "root_num", "%d", &num_roots);
-       if (err == -ENOENT) {
-               xenbus_dev_error(pdev->xdev, err,
-                                "No PCI Roots found, trying 0000:00");
-               err = pcifront_rescan_root(pdev, 0, 0);
-               if (err) {
-                       xenbus_dev_fatal(pdev->xdev, err,
-                                        "Error scanning PCI root 0000:00");
-                       goto out;
-               }
-               num_roots = 0;
-       } else if (err != 1) {
-               if (err == 0)
-                       err = -EINVAL;
-               xenbus_dev_fatal(pdev->xdev, err,
-                                "Error reading number of PCI roots");
-               goto out;
-       }
-
-       for (i = 0; i < num_roots; i++) {
-               len = snprintf(str, sizeof(str), "root-%d", i);
-               if (unlikely(len >= (sizeof(str) - 1))) {
-                       err = -ENOMEM;
-                       goto out;
-               }
-
-               err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
-                                  "%x:%x", &domain, &bus);
-               if (err != 2) {
-                       if (err >= 0)
-                               err = -EINVAL;
-                       xenbus_dev_fatal(pdev->xdev, err,
-                                        "Error reading PCI root %d", i);
-                       goto out;
-               }
-
-               err = pcifront_rescan_root(pdev, domain, bus);
-               if (err) {
-                       xenbus_dev_fatal(pdev->xdev, err,
-                                        "Error scanning PCI root %04x:%02x",
-                                        domain, bus);
-                       goto out;
-               }
-       }
-
-       xenbus_switch_state(pdev->xdev, XenbusStateConnected);
-
-out:
-       return err;
+               pcifront_connect(pdev);
 }
 
 static int pcifront_detach_devices(struct pcifront_device *pdev)