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-rw-r--r--fs/sysfs/file.c55
1 files changed, 55 insertions, 0 deletions
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index eb6897ab78e7..96d0da65e088 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -15,6 +15,7 @@
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/seq_file.h>
+#include <linux/mm.h>
#include "sysfs.h"
@@ -707,3 +708,57 @@ int sysfs_change_owner(struct kobject *kobj, kuid_t kuid, kgid_t kgid)
return 0;
}
EXPORT_SYMBOL_GPL(sysfs_change_owner);
+
+/**
+ * sysfs_emit - scnprintf equivalent, aware of PAGE_SIZE buffer.
+ * @buf: start of PAGE_SIZE buffer.
+ * @fmt: format
+ * @...: optional arguments to @format
+ *
+ *
+ * Returns number of characters written to @buf.
+ */
+int sysfs_emit(char *buf, const char *fmt, ...)
+{
+ va_list args;
+ int len;
+
+ if (WARN(!buf || offset_in_page(buf),
+ "invalid sysfs_emit: buf:%p\n", buf))
+ return 0;
+
+ va_start(args, fmt);
+ len = vscnprintf(buf, PAGE_SIZE, fmt, args);
+ va_end(args);
+
+ return len;
+}
+EXPORT_SYMBOL_GPL(sysfs_emit);
+
+/**
+ * sysfs_emit_at - scnprintf equivalent, aware of PAGE_SIZE buffer.
+ * @buf: start of PAGE_SIZE buffer.
+ * @at: offset in @buf to start write in bytes
+ * @at must be >= 0 && < PAGE_SIZE
+ * @fmt: format
+ * @...: optional arguments to @fmt
+ *
+ *
+ * Returns number of characters written starting at &@buf[@at].
+ */
+int sysfs_emit_at(char *buf, int at, const char *fmt, ...)
+{
+ va_list args;
+ int len;
+
+ if (WARN(!buf || offset_in_page(buf) || at < 0 || at >= PAGE_SIZE,
+ "invalid sysfs_emit_at: buf:%p at:%d\n", buf, at))
+ return 0;
+
+ va_start(args, fmt);
+ len = vscnprintf(buf + at, PAGE_SIZE - at, fmt, args);
+ va_end(args);
+
+ return len;
+}
+EXPORT_SYMBOL_GPL(sysfs_emit_at);