[PATCHv11 1/4] debugfs: add get/set for atomic types

From: Seth Jennings <sjenning@linux.vnet.ibm.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Seth Jennings <sjenning@linux.vnet.ibm.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Nitin Gupta <ngupta@vflare.org>, Minchan Kim <minchan@kernel.org>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	Dan Magenheimer <dan.magenheimer@oracle.com>,
	Robert Jennings <rcj@linux.vnet.ibm.com>,
	Jenifer Hopper <jhopper@us.ibm.com>, Mel Gorman <mgorman@suse.de>,
	Johannes Weiner <jweiner@redhat.com>,
	Rik van Riel <riel@redhat.com>,
	Larry Woodman <lwoodman@redhat.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Dave Hansen <dave@sr71.net>, Joe Perches <joe@perches.com>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	Cody P Schafer <cody@linux.vnet.ibm.com>,
	Hugh Dickens <hughd@google.com>,
	Paul Mackerras <paulus@samba.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	devel@driverdev.osuosl.org
Subject: [PATCHv11 1/4] debugfs: add get/set for atomic types
Date: Mon, 13 May 2013 07:40:00 -0500	[thread overview]
Message-ID: <1368448803-2089-2-git-send-email-sjenning@linux.vnet.ibm.com> (raw)
In-Reply-To: <1368448803-2089-1-git-send-email-sjenning@linux.vnet.ibm.com>

debugfs currently lack the ability to create attributes
that set/get atomic_t values.

This patch adds support for this through a new
debugfs_create_atomic_t() function.

Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Mel Gorman <mgorman@suse.de>
---
 fs/debugfs/file.c       |   42 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/debugfs.h |    2 ++
 lib/fault-inject.c      |   21 ---------------------
 3 files changed, 44 insertions(+), 21 deletions(-)

diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index c5ca6ae..ff64bcd 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -21,6 +21,7 @@
 #include <linux/debugfs.h>
 #include <linux/io.h>
 #include <linux/slab.h>
+#include <linux/atomic.h>
 
 static ssize_t default_read_file(struct file *file, char __user *buf,
 				 size_t count, loff_t *ppos)
@@ -403,6 +404,47 @@ struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
 }
 EXPORT_SYMBOL_GPL(debugfs_create_size_t);
 
+static int debugfs_atomic_t_set(void *data, u64 val)
+{
+	atomic_set((atomic_t *)data, val);
+	return 0;
+}
+static int debugfs_atomic_t_get(void *data, u64 *val)
+{
+	*val = atomic_read((atomic_t *)data);
+	return 0;
+}
+DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
+			debugfs_atomic_t_set, "%lld\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t_ro, debugfs_atomic_t_get, NULL, "%lld\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t_wo, NULL, debugfs_atomic_t_set, "%lld\n");
+
+/**
+ * debugfs_create_atomic_t - create a debugfs file that is used to read and
+ * write an atomic_t value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ */
+struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
+				 struct dentry *parent, atomic_t *value)
+{
+	/* if there are no write bits set, make read only */
+	if (!(mode & S_IWUGO))
+		return debugfs_create_file(name, mode, parent, value,
+					&fops_atomic_t_ro);
+	/* if there are no read bits set, make write only */
+	if (!(mode & S_IRUGO))
+		return debugfs_create_file(name, mode, parent, value,
+					&fops_atomic_t_wo);
+
+	return debugfs_create_file(name, mode, parent, value, &fops_atomic_t);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_atomic_t);
 
 static ssize_t read_file_bool(struct file *file, char __user *user_buf,
 			      size_t count, loff_t *ppos)
diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h
index 63f2465..d68b4ea 100644
--- a/include/linux/debugfs.h
+++ b/include/linux/debugfs.h
@@ -79,6 +79,8 @@ struct dentry *debugfs_create_x64(const char *name, umode_t mode,
 				  struct dentry *parent, u64 *value);
 struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
 				     struct dentry *parent, size_t *value);
+struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
+				     struct dentry *parent, atomic_t *value);
 struct dentry *debugfs_create_bool(const char *name, umode_t mode,
 				  struct dentry *parent, u32 *value);
 
diff --git a/lib/fault-inject.c b/lib/fault-inject.c
index c5c7a76..d7d501e 100644
--- a/lib/fault-inject.c
+++ b/lib/fault-inject.c
@@ -182,27 +182,6 @@ static struct dentry *debugfs_create_stacktrace_depth(
 
 #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
 
-static int debugfs_atomic_t_set(void *data, u64 val)
-{
-	atomic_set((atomic_t *)data, val);
-	return 0;
-}
-
-static int debugfs_atomic_t_get(void *data, u64 *val)
-{
-	*val = atomic_read((atomic_t *)data);
-	return 0;
-}
-
-DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
-			debugfs_atomic_t_set, "%lld\n");
-
-static struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
-				struct dentry *parent, atomic_t *value)
-{
-	return debugfs_create_file(name, mode, parent, value, &fops_atomic_t);
-}
-
 struct dentry *fault_create_debugfs_attr(const char *name,
 			struct dentry *parent, struct fault_attr *attr)
 {
-- 
1.7.9.5

