[PATCH 01/18] flag parameters: helper function

[Ulrich Drepper <drepper@redhat.com>]

In the following patches we have to map one set of flags to another one
in numerous locations.  This patch provides a generic implementation for
this.  It is basically the code Davide Libenzi suggested on 4/27/08.

I haven't checked whether this functionality can be applied to any existing
code.


 include/linux/flagsremap.h |   15 +++++++++++++++
 lib/Makefile               |    2 +-
 lib/flagsremap.c           |   17 +++++++++++++++++
 3 files changed, 33 insertions(+), 1 deletion(-)


Signed-off-by: Ulrich Drepper <drepper@redhat.com>

diff --git a/include/linux/flagsremap.h b/include/linux/flagsremap.h
new file mode 100644
index 0000000..6ea0ee3
--- /dev/null
+++ b/include/linux/flagsremap.h
@@ -0,0 +1,15 @@
+/*
+ * Generic flag remapping functionality.
+ */
+#ifndef _LINUX_FLAPREMAP_H
+#define _LINUX_FLAGREMAP_H
+
+struct flags_rmap {
+	int f;
+	int of;
+};
+
+extern int flags_remap(const struct flags_rmap *m, int n,
+		       int f, int *rf);
+
+#endif /* _LINUX_FLAGREMAP_H */
diff --git a/lib/Makefile b/lib/Makefile
index 74b0cfb..ab861ad 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -6,7 +6,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \
 	 rbtree.o radix-tree.o dump_stack.o \
 	 idr.o int_sqrt.o extable.o prio_tree.o \
 	 sha1.o irq_regs.o reciprocal_div.o argv_split.o \
-	 proportions.o prio_heap.o ratelimit.o
+	 proportions.o prio_heap.o ratelimit.o flagsremap.o
 
 lib-$(CONFIG_MMU) += ioremap.o
 lib-$(CONFIG_SMP) += cpumask.o
diff --git a/lib/flagsremap.c b/lib/flagsremap.c
new file mode 100644
index 0000000..7dbe8f5
--- /dev/null
+++ b/lib/flagsremap.c
@@ -0,0 +1,17 @@
+/*
+ * Implement generic flag remapping.
+ */
+#include <linux/flagsremap.h>
+
+
+int flags_remap(const struct flags_rmap *m, int n,
+		int f, int *rf)
+{
+	int i;
+	for (i = 0, *rf = 0; f && i < n; i++, m++)
+		if (f & m->f) {
+			*rf |= m->of;
+			f &= ~m->f;
+		}
+	return f;
+}