[SCSI] ibmvfc: Support FAST_IO_FAIL in EH handlers

[~andy/linux] / drivers / pps / pps.c

diff --git a/drivers/pps/pps.c b/drivers/pps/pps.c
index e771487132f7542123a0e8a669cd8582481ab051..7173e3ad475d9d9f8e6a169106691c18ad2fea56 100644 (file)
--- a/drivers/pps/pps.c
+++ b/drivers/pps/pps.c
@@ -247,12 +247,15 @@ static int pps_cdev_open(struct inode *inode, struct file *file)
        struct pps_device *pps = container_of(inode->i_cdev,
                                                struct pps_device, cdev);
        file->private_data = pps;
-
+       kobject_get(&pps->dev->kobj);
        return 0;
 }
 
 static int pps_cdev_release(struct inode *inode, struct file *file)
 {
+       struct pps_device *pps = container_of(inode->i_cdev,
+                                               struct pps_device, cdev);
+       kobject_put(&pps->dev->kobj);
        return 0;
 }
 
@@ -274,8 +277,10 @@ static void pps_device_destruct(struct device *dev)
 {
        struct pps_device *pps = dev_get_drvdata(dev);
 
-       /* release id here to protect others from using it while it's
-        * still in use */
+       cdev_del(&pps->cdev);
+
+       /* Now we can release the ID for re-use */
+       pr_debug("deallocating pps%d\n", pps->id);
        mutex_lock(&pps_idr_lock);
        idr_remove(&pps_idr, pps->id);
        mutex_unlock(&pps_idr_lock);
@@ -290,29 +295,21 @@ int pps_register_cdev(struct pps_device *pps)
        dev_t devt;
 
        mutex_lock(&pps_idr_lock);
-       /* Get new ID for the new PPS source */
-       if (idr_pre_get(&pps_idr, GFP_KERNEL) == 0) {
-               mutex_unlock(&pps_idr_lock);
-               return -ENOMEM;
-       }
-
-       /* Now really allocate the PPS source.
-        * After idr_get_new() calling the new source will be freely available
-        * into the kernel.
+       /*
+        * Get new ID for the new PPS source.  After idr_alloc() calling
+        * the new source will be freely available into the kernel.
         */
-       err = idr_get_new(&pps_idr, pps, &pps->id);
-       mutex_unlock(&pps_idr_lock);
-
-       if (err < 0)
-               return err;
-
-       pps->id &= MAX_ID_MASK;
-       if (pps->id >= PPS_MAX_SOURCES) {
-               pr_err("%s: too many PPS sources in the system\n",
-                                       pps->info.name);
-               err = -EBUSY;
-               goto free_idr;
+       err = idr_alloc(&pps_idr, pps, 0, PPS_MAX_SOURCES, GFP_KERNEL);
+       if (err < 0) {
+               if (err == -ENOSPC) {
+                       pr_err("%s: too many PPS sources in the system\n",
+                              pps->info.name);
+                       err = -EBUSY;
+               }
+               goto out_unlock;
        }
+       pps->id = err;
+       mutex_unlock(&pps_idr_lock);
 
        devt = MKDEV(MAJOR(pps_devt), pps->id);
 
@@ -332,6 +329,7 @@ int pps_register_cdev(struct pps_device *pps)
                goto del_cdev;
        }
 
+       /* Override the release function with our own */
        pps->dev->release = pps_device_destruct;
 
        pr_debug("source %s got cdev (%d:%d)\n", pps->info.name,
@@ -345,17 +343,50 @@ del_cdev:
 free_idr:
        mutex_lock(&pps_idr_lock);
        idr_remove(&pps_idr, pps->id);
+out_unlock:
        mutex_unlock(&pps_idr_lock);
-
        return err;
 }
 
 void pps_unregister_cdev(struct pps_device *pps)
 {
+       pr_debug("unregistering pps%d\n", pps->id);
+       pps->lookup_cookie = NULL;
        device_destroy(pps_class, pps->dev->devt);
-       cdev_del(&pps->cdev);
 }
 
+/*
+ * Look up a pps device by magic cookie.
+ * The cookie is usually a pointer to some enclosing device, but this
+ * code doesn't care; you should never be dereferencing it.
+ *
+ * This is a bit of a kludge that is currently used only by the PPS
+ * serial line discipline.  It may need to be tweaked when a second user
+ * is found.
+ *
+ * There is no function interface for setting the lookup_cookie field.
+ * It's initialized to NULL when the pps device is created, and if a
+ * client wants to use it, just fill it in afterward.
+ *
+ * The cookie is automatically set to NULL in pps_unregister_source()
+ * so that it will not be used again, even if the pps device cannot
+ * be removed from the idr due to pending references holding the minor
+ * number in use.
+ */
+struct pps_device *pps_lookup_dev(void const *cookie)
+{
+       struct pps_device *pps;
+       unsigned id;
+
+       rcu_read_lock();
+       idr_for_each_entry(&pps_idr, pps, id)
+               if (cookie == pps->lookup_cookie)
+                       break;
+       rcu_read_unlock();
+       return pps;
+}
+EXPORT_SYMBOL(pps_lookup_dev);
+
 /*
  * Module stuff
  */