X-Git-Url: http://pilppa.org/gitweb/?a=blobdiff_plain;f=fs%2Fsysfs%2Fgroup.c;h=eeba38417b1d4c5db2a54e381fb68b8441eb7743;hb=cc55875e26e2b85484b196edbada6caf84eb7765;hp=f318b73c790c8d2b058bd68ac6646b2adb550802;hpb=2e85622042cb5fd56a606e884651ffde52f21028;p=linux-2.6-omap-h63xx.git

diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
index f318b73c790..eeba38417b1 100644
--- a/fs/sysfs/group.c
+++ b/fs/sysfs/group.c
@@ -13,41 +13,60 @@
 #include <linux/dcache.h>
 #include <linux/namei.h>
 #include <linux/err.h>
-#include <linux/fs.h>
-#include <asm/semaphore.h>
 #include "sysfs.h"
 
 
-static void remove_files(struct sysfs_dirent *dir_sd,
+static void remove_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
 			 const struct attribute_group *grp)
 {
 	struct attribute *const* attr;
+	int i;
 
-	for (attr = grp->attrs; *attr; attr++)
+	for (i = 0, attr = grp->attrs; *attr; i++, attr++)
 		sysfs_hash_and_remove(dir_sd, (*attr)->name);
 }
 
-static int create_files(struct sysfs_dirent *dir_sd,
-			const struct attribute_group *grp)
+static int create_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
+			const struct attribute_group *grp, int update)
 {
 	struct attribute *const* attr;
-	int error = 0;
-
-	for (attr = grp->attrs; *attr && !error; attr++)
-		error = sysfs_add_file(dir_sd, *attr, SYSFS_KOBJ_ATTR);
+	int error = 0, i;
+
+	for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
+		mode_t mode = 0;
+
+		/* in update mode, we're changing the permissions or
+		 * visibility.  Do this by first removing then
+		 * re-adding (if required) the file */
+		if (update)
+			sysfs_hash_and_remove(dir_sd, (*attr)->name);
+		if (grp->is_visible) {
+			mode = grp->is_visible(kobj, *attr, i);
+			if (!mode)
+				continue;
+		}
+		error = sysfs_add_file_mode(dir_sd, *attr, SYSFS_KOBJ_ATTR,
+					    (*attr)->mode | mode);
+		if (unlikely(error))
+			break;
+	}
 	if (error)
-		remove_files(dir_sd, grp);
+		remove_files(dir_sd, kobj, grp);
 	return error;
 }
 
 
-int sysfs_create_group(struct kobject * kobj, 
-		       const struct attribute_group * grp)
+static int internal_create_group(struct kobject *kobj, int update,
+				 const struct attribute_group *grp)
 {
 	struct sysfs_dirent *sd;
 	int error;
 
-	BUG_ON(!kobj || !kobj->sd);
+	BUG_ON(!kobj || (!update && !kobj->sd));
+
+	/* Updates may happen before the object has been instantiated */
+	if (unlikely(update && !kobj->sd))
+		return -EINVAL;
 
 	if (grp->name) {
 		error = sysfs_create_subdir(kobj, grp->name, &sd);
@@ -56,7 +75,7 @@ int sysfs_create_group(struct kobject * kobj,
 	} else
 		sd = kobj->sd;
 	sysfs_get(sd);
-	error = create_files(sd, grp);
+	error = create_files(sd, kobj, grp, update);
 	if (error) {
 		if (grp->name)
 			sysfs_remove_subdir(sd);
@@ -65,6 +84,47 @@ int sysfs_create_group(struct kobject * kobj,
 	return error;
 }
 
+/**
+ * sysfs_create_group - given a directory kobject, create an attribute group
+ * @kobj:	The kobject to create the group on
+ * @grp:	The attribute group to create
+ *
+ * This function creates a group for the first time.  It will explicitly
+ * warn and error if any of the attribute files being created already exist.
+ *
+ * Returns 0 on success or error.
+ */
+int sysfs_create_group(struct kobject *kobj,
+		       const struct attribute_group *grp)
+{
+	return internal_create_group(kobj, 0, grp);
+}
+
+/**
+ * sysfs_update_group - given a directory kobject, create an attribute group
+ * @kobj:	The kobject to create the group on
+ * @grp:	The attribute group to create
+ *
+ * This function updates an attribute group.  Unlike
+ * sysfs_create_group(), it will explicitly not warn or error if any
+ * of the attribute files being created already exist.  Furthermore,
+ * if the visibility of the files has changed through the is_visible()
+ * callback, it will update the permissions and add or remove the
+ * relevant files.
+ *
+ * The primary use for this function is to call it after making a change
+ * that affects group visibility.
+ *
+ * Returns 0 on success or error.
+ */
+int sysfs_update_group(struct kobject *kobj,
+		       const struct attribute_group *grp)
+{
+	return internal_create_group(kobj, 1, grp);
+}
+
+
+
 void sysfs_remove_group(struct kobject * kobj, 
 			const struct attribute_group * grp)
 {
@@ -73,11 +133,16 @@ void sysfs_remove_group(struct kobject * kobj,
 
 	if (grp->name) {
 		sd = sysfs_get_dirent(dir_sd, grp->name);
-		BUG_ON(!sd);
+		if (!sd) {
+			printk(KERN_WARNING "sysfs group %p not found for "
+				"kobject '%s'\n", grp, kobject_name(kobj));
+			WARN_ON(!sd);
+			return;
+		}
 	} else
 		sd = sysfs_get(dir_sd);
 
-	remove_files(sd, grp);
+	remove_files(sd, kobj, grp);
 	if (grp->name)
 		sysfs_remove_subdir(sd);
 
@@ -86,4 +151,5 @@ void sysfs_remove_group(struct kobject * kobj,
 
 
 EXPORT_SYMBOL_GPL(sysfs_create_group);
+EXPORT_SYMBOL_GPL(sysfs_update_group);
 EXPORT_SYMBOL_GPL(sysfs_remove_group);