textsearch: support for case insensitive searching

The function textsearch_prepare has a new flag to support case
insensitive searching.
Signed-off-by: NJoonwoo Park <joonwpark81@gmail.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/linux/textsearch.h

@@ -10,10 +10,8 @@
 
 struct ts_config;
 
-/**
- * TS_AUTOLOAD - Automatically load textsearch modules when needed
- */
-#define TS_AUTOLOAD	1
+#define TS_AUTOLOAD	1 /* Automatically load textsearch modules when needed */
+#define TS_IGNORECASE	2 /* Searches string case insensitively */
 
 /**
  * struct ts_state - search state
@@ -39,7 +37,7 @@ struct ts_state
 struct ts_ops
 {
 	const char		*name;
-	struct ts_config *	(*init)(const void *, unsigned int, gfp_t);
+	struct ts_config *	(*init)(const void *, unsigned int, gfp_t, int);
 	unsigned int		(*find)(struct ts_config *,
 					struct ts_state *);
 	void			(*destroy)(struct ts_config *);
@@ -52,12 +50,14 @@ struct ts_ops
 /**
  * struct ts_config - search configuration
  * @ops: operations of chosen algorithm
+ * @flags: flags
  * @get_next_block: callback to fetch the next block to search in
  * @finish: callback to finalize a search
  */
 struct ts_config
 {
 	struct ts_ops		*ops;
+	int 			flags;
 
 	/**
 	 * get_next_block - fetch next block of data

lib/textsearch.c

@@ -54,10 +54,13 @@
  * USAGE
  *
  *   Before a search can be performed, a configuration must be created
- *   by calling textsearch_prepare() specyfing the searching algorithm and
- *   the pattern to look for. The returned configuration may then be used
- *   for an arbitary amount of times and even in parallel as long as a
- *   separate struct ts_state variable is provided to every instance.
+ *   by calling textsearch_prepare() specifying the searching algorithm,
+ *   the pattern to look for and flags. As a flag, you can set TS_IGNORECASE
+ *   to perform case insensitive matching. But it might slow down
+ *   performance of algorithm, so you should use it at own your risk.
+ *   The returned configuration may then be used for an arbitary
+ *   amount of times and even in parallel as long as a separate struct
+ *   ts_state variable is provided to every instance.
  *
  *   The actual search is performed by either calling textsearch_find_-
  *   continuous() for linear data or by providing an own get_next_block()
@@ -89,7 +92,6 @@
  *       panic("Oh my god, dancing chickens at %d\n", pos);
  *
  *   textsearch_destroy(conf);
- *
  * ==========================================================================
  */
 
@@ -279,7 +281,7 @@ struct ts_config *textsearch_prepare(const char *algo, const void *pattern,
 	if (ops == NULL)
 		goto errout;
 
-	conf = ops->init(pattern, len, gfp_mask);
+	conf = ops->init(pattern, len, gfp_mask, flags);
 	if (IS_ERR(conf)) {
 		err = PTR_ERR(conf);
 		goto errout;