add prefix to fs_context->log

... turning it into struct p_log embedded into fs_context.  Initialize
the prefix with fs_type->name, turning fs_parse() into a trivial
inline wrapper for __fs_parse().

This makes fs_parameter_description->name completely unused.

Signed-off-by: Al Viro <[email protected]>
diff --git a/include/linux/fs_context.h b/include/linux/fs_context.h
index 41f37d3..b2ad9b0 100644
--- a/include/linux/fs_context.h
+++ b/include/linux/fs_context.h
@@ -97,7 +97,7 @@ struct fs_context {
 	struct user_namespace	*user_ns;	/* The user namespace for this mount */
 	struct net		*net_ns;	/* The network namespace for this mount */
 	const struct cred	*cred;		/* The mounter's credentials */
-	struct fc_log		*log;		/* Logging buffer */
+	struct p_log		log;		/* Logging buffer */
 	const char		*source;	/* The source name (eg. dev path) */
 	void			*security;	/* Linux S&M options */
 	void			*s_fs_info;	/* Proposed s_fs_info */
@@ -189,7 +189,7 @@ struct fc_log {
 extern __attribute__((format(printf, 4, 5)))
 void logfc(struct fc_log *log, const char *prefix, char level, const char *fmt, ...);
 
-#define __logfc(fc, l, fmt, ...) logfc((fc)->log, NULL, \
+#define __logfc(fc, l, fmt, ...) logfc((fc)->log.log, NULL, \
 					l, fmt, ## __VA_ARGS__)
 #define __plog(p, l, fmt, ...) logfc((p)->log, (p)->prefix, \
 					l, fmt, ## __VA_ARGS__)