[PATCH 3/7] fuse: Make cuse_parse_one a common helper

[Richard Weinberger]

This function will be used by MUSE too, let's share it.

Signed-off-by: Richard Weinberger <richard@xxxxxx>
---
 fs/fuse/Kconfig  |  4 +++
 fs/fuse/Makefile |  1 +
 fs/fuse/cuse.c   | 58 +--------------------------------------
 fs/fuse/fuse_i.h |  2 ++
 fs/fuse/helper.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 78 insertions(+), 57 deletions(-)
 create mode 100644 fs/fuse/helper.c

diff --git a/fs/fuse/Kconfig b/fs/fuse/Kconfig
index 40ce9a1c12e5..9c8cc1e7b3a5 100644
--- a/fs/fuse/Kconfig
+++ b/fs/fuse/Kconfig
@@ -18,9 +18,13 @@ config FUSE_FS
 	  If you want to develop a userspace FS, or if you want to use
 	  a filesystem based on FUSE, answer Y or M.
 
+config FUSE_HELPER
+	def_bool n
+
 config CUSE
 	tristate "Character device in Userspace support"
 	depends on FUSE_FS
+	select FUSE_HELPER
 	help
 	  This FUSE extension allows character devices to be
 	  implemented in userspace.
diff --git a/fs/fuse/Makefile b/fs/fuse/Makefile
index 8c7021fb2cd4..7a5768cce6be 100644
--- a/fs/fuse/Makefile
+++ b/fs/fuse/Makefile
@@ -9,5 +9,6 @@ obj-$(CONFIG_VIRTIO_FS) += virtiofs.o
 
 fuse-y := dev.o dir.o file.o inode.o control.o xattr.o acl.o readdir.o
 fuse-$(CONFIG_FUSE_DAX) += dax.o
+fuse-$(CONFIG_FUSE_HELPER) += helper.o
 
 virtiofs-y := virtio_fs.o
diff --git a/fs/fuse/cuse.c b/fs/fuse/cuse.c
index 45082269e698..fe8515844064 100644
--- a/fs/fuse/cuse.c
+++ b/fs/fuse/cuse.c
@@ -199,62 +199,6 @@ struct cuse_devinfo {
 	const char		*name;
 };
 
-/**
- * cuse_parse_one - parse one key=value pair
- * @pp: i/o parameter for the current position
- * @end: points to one past the end of the packed string
- * @keyp: out parameter for key
- * @valp: out parameter for value
- *
- * *@pp points to packed strings - "key0=val0\0key1=val1\0" which ends
- * at @end - 1.  This function parses one pair and set *@keyp to the
- * start of the key and *@valp to the start of the value.  Note that
- * the original string is modified such that the key string is
- * terminated with '\0'.  *@pp is updated to point to the next string.
- *
- * RETURNS:
- * 1 on successful parse, 0 on EOF, -errno on failure.
- */
-static int cuse_parse_one(char **pp, char *end, char **keyp, char **valp)
-{
-	char *p = *pp;
-	char *key, *val;
-
-	while (p < end && *p == '\0')
-		p++;
-	if (p == end)
-		return 0;
-
-	if (end[-1] != '\0') {
-		pr_err("info not properly terminated\n");
-		return -EINVAL;
-	}
-
-	key = val = p;
-	p += strlen(p);
-
-	if (valp) {
-		strsep(&val, "=");
-		if (!val)
-			val = key + strlen(key);
-		key = strstrip(key);
-		val = strstrip(val);
-	} else
-		key = strstrip(key);
-
-	if (!strlen(key)) {
-		pr_err("zero length info key specified\n");
-		return -EINVAL;
-	}
-
-	*pp = p;
-	*keyp = key;
-	if (valp)
-		*valp = val;
-
-	return 1;
-}
-
 /**
  * cuse_parse_dev_info - parse device info
  * @p: device info string
@@ -275,7 +219,7 @@ static int cuse_parse_devinfo(char *p, size_t len, struct cuse_devinfo *devinfo)
 	int rc;
 
 	while (true) {
-		rc = cuse_parse_one(&p, end, &key, &val);
+		rc = fuse_kv_parse_one(&p, end, &key, &val);
 		if (rc < 0)
 			return rc;
 		if (!rc)
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index d23954908610..8eba93cd8fb8 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -1225,5 +1225,7 @@ void fuse_dax_cancel_work(struct fuse_conn *fc);
 /* file.c */
 struct page **fuse_pages_alloc(unsigned int npages, gfp_t flags,
 			       struct fuse_page_desc **desc);
+/* helper.c */
+int fuse_kv_parse_one(char **pp, char *end, char **keyp, char **valp);
 
 #endif /* _FS_FUSE_I_H */
diff --git a/fs/fuse/helper.c b/fs/fuse/helper.c
new file mode 100644
index 000000000000..0c828daf8e8a
--- /dev/null
+++ b/fs/fuse/helper.c
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Helper functions used by CUSE and MUSE
+ *
+ * Copyright (C) 2008-2009  SUSE Linux Products GmbH
+ * Copyright (C) 2008-2009  Tejun Heo <tj@xxxxxxxxxx>
+ *
+ */
+
+#include <linux/string.h>
+#include <linux/module.h>
+
+#include "fuse_i.h"
+
+/**
+ * fuse_kv_parse_one - parse one key=value pair
+ * @pp: i/o parameter for the current position
+ * @end: points to one past the end of the packed string
+ * @keyp: out parameter for key
+ * @valp: out parameter for value
+ *
+ * *@pp points to packed strings - "key0=val0\0key1=val1\0" which ends
+ * at @end - 1.  This function parses one pair and set *@keyp to the
+ * start of the key and *@valp to the start of the value.  Note that
+ * the original string is modified such that the key string is
+ * terminated with '\0'.  *@pp is updated to point to the next string.
+ *
+ * RETURNS:
+ * 1 on successful parse, 0 on EOF, -errno on failure.
+ */
+int fuse_kv_parse_one(char **pp, char *end, char **keyp, char **valp)
+{
+	char *p = *pp;
+	char *key, *val;
+
+	while (p < end && *p == '\0')
+		p++;
+	if (p == end)
+		return 0;
+
+	if (end[-1] != '\0') {
+		pr_err("info not properly terminated\n");
+		return -EINVAL;
+	}
+
+	key = val = p;
+	p += strlen(p);
+
+	if (valp) {
+		strsep(&val, "=");
+		if (!val)
+			val = key + strlen(key);
+		key = strstrip(key);
+		val = strstrip(val);
+	} else
+		key = strstrip(key);
+
+	if (!strlen(key)) {
+		pr_err("zero length info key specified\n");
+		return -EINVAL;
+	}
+
+	*pp = p;
+	*keyp = key;
+	if (valp)
+		*valp = val;
+
+	return 1;
+}
+EXPORT_SYMBOL_GPL(fuse_kv_parse_one);
-- 
2.26.2