efivars: Make efivars bin_attributes dynamic

In preparation for encapsulating efivars, we need to have the
bin_attributes be dynamically allocated so that we can use their
->private fields to get back to the struct efivars structure.

Signed-off-by: Mike Waychison <mikew@google.com>
Cc: Matt Domsch <Matt_Domsch@dell.com>,
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 68 insertions, 25 deletions

diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index f10ecb6d04b2..528ce47c1368 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -101,6 +101,7 @@ struct efivars {
         spinlock_t lock;
         struct list_head list;
         struct kset *kset;
+        struct bin_attribute *new_var, *del_var;
 };
 static struct efivars __efivars;
 static struct efivars *efivars = &__efivars;
@@ -525,16 +526,6 @@ static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
         return count;
 }
 
-static struct bin_attribute var_subsys_attr_new_var = {
-        .attr = {.name = "new_var", .mode = 0200},
-        .write = efivar_create,
-};
-
-static struct bin_attribute var_subsys_attr_del_var = {
-        .attr = {.name = "del_var", .mode = 0200},
-        .write = efivar_delete,
-};
-
 /*
  * Let's not leave out systab information that snuck into
  * the efivars driver
@@ -640,6 +631,66 @@ efivar_create_sysfs_entry(unsigned long variable_name_size,
 
         return 0;
 }
+
+static int
+create_efivars_bin_attributes(struct efivars *efivars)
+{
+        struct bin_attribute *attr;
+        int error;
+
+        /* new_var */
+        attr = kzalloc(sizeof(*attr), GFP_KERNEL);
+        if (!attr)
+                return -ENOMEM;
+
+        attr->attr.name = "new_var";
+        attr->attr.mode = 0200;
+        attr->write = efivar_create;
+        attr->private = efivars;
+        efivars->new_var = attr;
+
+        /* del_var */
+        attr = kzalloc(sizeof(*attr), GFP_KERNEL);
+        if (!attr) {
+                error = -ENOMEM;
+                goto out_free;
+        }
+        attr->attr.name = "del_var";
+        attr->attr.mode = 0200;
+        attr->write = efivar_delete;
+        attr->private = efivars;
+        efivars->del_var = attr;
+
+        sysfs_bin_attr_init(efivars->new_var);
+        sysfs_bin_attr_init(efivars->del_var);
+
+        /* Register */
+        error = sysfs_create_bin_file(&efivars->kset->kobj,
+                                      efivars->new_var);
+        if (error) {
+                printk(KERN_ERR "efivars: unable to create new_var sysfs file"
+                        " due to error %d\n", error);
+                goto out_free;
+        }
+        error = sysfs_create_bin_file(&efivars->kset->kobj,
+                                      efivars->del_var);
+        if (error) {
+                printk(KERN_ERR "efivars: unable to create del_var sysfs file"
+                        " due to error %d\n", error);
+                sysfs_remove_bin_file(&efivars->kset->kobj,
+                                      efivars->new_var);
+                goto out_free;
+        }
+
+        return 0;
+out_free:
+        kfree(efivars->new_var);
+        efivars->new_var = NULL;
+        kfree(efivars->new_var);
+        efivars->new_var = NULL;
+        return error;
+}
+
 /*
  * For now we register the efi subsystem with the firmware subsystem
  * and the vars subsystem with the efi subsystem.  In the future, it
@@ -714,20 +765,7 @@ efivars_init(void)
                 }
         } while (status != EFI_NOT_FOUND);
 
-        /*
-         * Now add attributes to allow creation of new vars
-         * and deletion of existing ones...
-         */
-        error = sysfs_create_bin_file(&efivars->kset->kobj,
-                                      &var_subsys_attr_new_var);
-        if (error)
-                printk(KERN_ERR "efivars: unable to create new_var sysfs file"
-                        " due to error %d\n", error);
-        error = sysfs_create_bin_file(&efivars->kset->kobj,
-                                      &var_subsys_attr_del_var);
-        if (error)
-                printk(KERN_ERR "efivars: unable to create del_var sysfs file"
-                        " due to error %d\n", error);
+        error = create_efivars_bin_attributes(efivars);
 
         /* Don't forget the systab entry */
         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
@@ -758,7 +796,12 @@ efivars_exit(void)
                 spin_unlock(&efivars->lock);
                 efivar_unregister(entry);
         }
-
+        if (efivars->new_var)
+                sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
+        if (efivars->del_var)
+                sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
+        kfree(efivars->new_var);
+        kfree(efivars->del_var);
         kset_unregister(efivars->kset);
         kobject_put(efi_kobj);
 }