chiark / gitweb /
[PATCH] try to wait until the proper device file shows up in sysfs.
authorgreg@kroah.com <greg@kroah.com>
Sat, 20 Dec 2003 09:05:13 +0000 (01:05 -0800)
committerGreg KH <gregkh@suse.de>
Wed, 27 Apr 2005 04:13:09 +0000 (21:13 -0700)
this still isn't working correctly for partitions, so don't
think this is the final version...

namedev.c

index 58986e2..30c276a 100644 (file)
--- a/namedev.c
+++ b/namedev.c
@@ -30,6 +30,7 @@
 #include <unistd.h>
 #include <errno.h>
 #include <sys/wait.h>
+#include <sys/stat.h>
 
 #include "list.h"
 #include "udev.h"
@@ -284,6 +285,55 @@ static void apply_format(struct udevice *udev, unsigned char *string)
        }
 }
 
+static struct bus_file {
+       char *bus;
+       char *file;
+} bus_files[] = {
+       { .bus = "scsi",        .file = "vendor" },
+       { .bus = "usb",         .file = "idVendor" },
+       {}
+};
+
+#define SECONDS_TO_WAIT_FOR_FILE       10
+static void wait_for_device_to_initialize(struct sysfs_device *sysfs_device)
+{
+       /* sleep until we see the file for this specific bus type show up this
+        * is needed because we can easily out-run the kernel in looking for
+        * these files before the paticular subsystem has created them in the
+        * sysfs tree properly.
+        *
+        * And people thought that the /sbin/hotplug event system was going to
+        * be slow, poo on you for arguing that before even testing it...
+        */
+       struct bus_file *b = &bus_files[0];
+       struct sysfs_attribute *tmpattr;
+       int loop;
+
+       while (1) {
+               if (b->bus == NULL)
+                       break;
+               if (strcmp(sysfs_device->bus, b->bus) == 0) {
+                       tmpattr = NULL;
+                       loop = SECONDS_TO_WAIT_FOR_FILE;
+                       while (loop--) {
+                               dbg("looking for file '%s' on bus '%s'", b->file, b->bus);
+                               tmpattr = sysfs_get_device_attr(sysfs_device, b->file);
+                               if (tmpattr) {
+                                       /* found it! */
+                                       goto exit;
+                               }
+                               /* sleep to give the kernel a chance to create the file */
+                               sleep(1);
+                       }
+                       dbg("Timed out waiting for '%s' file, continuing on anyway...", b->file);
+                       goto exit;
+               }
+               b++;
+       }
+       dbg("Did not find bus type '%s' on list of bus_id_files, contact greg@kroah.com", sysfs_device->bus);
+exit:
+       return; /* here to prevent compiler warning... */
+}
 
 static int exec_callout(struct config_device *dev, char *value, int len)
 {
@@ -580,19 +630,84 @@ static void do_kernelname(struct sysfs_class_device *class_dev, struct udevice *
        strfieldcpy(udev->name, class_dev->name);
 }
 
-int namedev_name_device(struct sysfs_class_device *class_dev, struct udevice *udev)
+static struct sysfs_device *get_sysfs_device(struct sysfs_class_device *class_dev)
 {
-       struct sysfs_device *sysfs_device = NULL;
-       struct sysfs_class_device *class_dev_parent = NULL;
-       int retval = 0;
-       struct perm_device *perm;
+       struct sysfs_device *sysfs_device;
+       struct sysfs_class_device *class_dev_parent;
+       int loop;
+       int retval;
+       char filename[SYSFS_PATH_MAX + 6];
+
+       /* FIXME!!! */
+       /* This is needed here as we can easily out-race the placement of the
+        * device symlink by the kernel.  The call to sleep(1); will be removed
+        * once libsysfs can be queried for sysfs_get_classdev_device()
+        * multiple times and have it return the proper information when the
+        * class device really shows up.  For now, we live with the time
+        * delay...
+        */
+//     sleep(1);
+       loop = 10;
+       while (loop--) {
+               struct stat buf;
+
+               strcpy(filename, class_dev->path);
+               strcat(filename, "/device");
+               dbg("looking for '%s'", filename);
+               retval = stat(filename, &buf);
+               if (!retval)
+                       break;
+#if 0
+               /* bah, let's go backwards up a level to see if the device is there,
+                * as block partitions don't point to the physical device.  Need to fix that
+                * up in the kernel...
+                */
+               if (strcmp(class_dev->classname, SYSFS_BLOCK_NAME) == 0) {
+                       if (isdigit(class_dev->path[strlen(class_dev->path)-1])) {
+                               char *temp = strrchr(filename, '/');
+                               if (temp) {
+                                       *temp = 0x00;
+                                       temp = strrchr(filename, '/');
+                                       if (temp) {
+                                               *temp = 0x00;
+                                               strcat(filename, "/device");
+                                               dbg("looking for '%s'", filename);
+                                               retval = stat(filename, &buf);
+                                               if (!retval)
+                                                       break;
+                                       }
+                               }
+                       }
+               }
+#endif
+//                             class_dev_parent = sysfs_get_classdev_parent(class_dev);
+//                             if (class_dev_parent == NULL) {
+//                                     dbg("sysfs_get_classdev_parent for class device '%s' failed", class_dev->name);
+//                             } else {
+//                                     strcpy(filename, class_dev_parent->path);
+//                                     strcat(filename, "/device");
+//                                     dbg("looking for '%s'", filename);
+//                                     retval = stat(filename, &buf);
+//                                     if (!retval)
+//                                             break;
+//                             }
+//                     }
+//             }
+               /* sleep to give the kernel a chance to create the device file */
+               sleep(1);
+       }
+//     retval = -ENODEV;
 
-       udev->mode = 0;
+//     sleep(1);
+
+       loop = 1;       /* FIXME put a real value in here for when everything is fixed... */
+       while (loop--) {
+               /* find the sysfs_device for this class device */
+               /* Wouldn't it really be nice if libsysfs could do this for us? */
+               sysfs_device = sysfs_get_classdev_device(class_dev);
+               if (sysfs_device != NULL)
+                       goto exit;
 
-       /* find the sysfs_device for this class device */
-       /* Wouldn't it really be nice if libsysfs could do this for us? */
-       sysfs_device = sysfs_get_classdev_device(class_dev);
-       if (sysfs_device == NULL) {
                /* bah, let's go backwards up a level to see if the device is there,
                 * as block partitions don't point to the physical device.  Need to fix that
                 * up in the kernel...
@@ -601,23 +716,43 @@ int namedev_name_device(struct sysfs_class_device *class_dev, struct udevice *ud
                        dbg("looking at block device");
                        if (isdigit(class_dev->path[strlen(class_dev->path)-1])) {
                                dbg("really is a partition");
-                               class_dev_parent = sysfs_get_classdev_parent
-                                                                  (class_dev);
+                               class_dev_parent = sysfs_get_classdev_parent(class_dev);
                                if (class_dev_parent == NULL) {
                                        dbg("sysfs_get_classdev_parent for class device '%s' failed", class_dev->name);
                                } else {
                                        dbg("class_dev_parent->name='%s'", class_dev_parent->name);
                                        sysfs_device = sysfs_get_classdev_device(class_dev_parent);
+                                       if (sysfs_device != NULL)
+                                               goto exit;
                                }
                        }
                }
+               /* sleep to give the kernel a chance to create the link */
+               /* sleep(1); */
+
        }
+//     dbg("Timed out waiting for device symlink, continuing on anyway...");
+exit:
+       return sysfs_device;
+}
+
+int namedev_name_device(struct sysfs_class_device *class_dev, struct udevice *udev)
+{
+       struct sysfs_device *sysfs_device = NULL;
+       struct sysfs_class_device *class_dev_parent = NULL;
+       int retval = 0;
+       struct perm_device *perm;
+
+       udev->mode = 0;
 
+       /* find the sysfs_device associated with this class device */
+       sysfs_device = get_sysfs_device(class_dev);
        if (sysfs_device) {
                dbg("sysfs_device->path='%s'", sysfs_device->path);
                dbg("sysfs_device->bus_id='%s'", sysfs_device->bus_id);
                dbg("sysfs_device->bus='%s'", sysfs_device->bus);
                strfieldcpy(udev->bus_id, sysfs_device->bus_id);
+               wait_for_device_to_initialize(sysfs_device);
        } else {
                dbg("class_dev->name = '%s'", class_dev->name);
        }