linux-kernel - [PATCH v2 13/24] dyndbg: combine flags & mask into a struct, use that

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Message-Id: <20200613155738.2249399-14-jim.cromie@gmail.com>
Date:   Sat, 13 Jun 2020 09:57:27 -0600
From:   Jim Cromie <jim.cromie@...il.com>
To:     jbaron@...mai.com, linux-kernel@...r.kernel.org,
        akpm@...uxfoundation.org, gregkh@...uxfoundation.org
Cc:     linux@...musvillemoes.dk, Jim Cromie <jim.cromie@...il.com>
Subject: [PATCH v2 13/24] dyndbg: combine flags & mask into a struct, use that

combine flags & mask into a struct, and replace those 2 parameters in
3 functions: ddebug_change, ddebug_parse_flags, ddebug_read_flags,
altering the derefs in them accordingly.

This simplifies the 3 function sigs, preparing for more changes.
We dont yet need mask from ddebug_read_flags, but will soon.
---
 lib/dynamic_debug.c | 46 +++++++++++++++++++++++----------------------
 1 file changed, 24 insertions(+), 22 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 93c627e9c094..8dc073a6e8a4 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -62,6 +62,11 @@ struct ddebug_iter {
 	unsigned int idx;
 };
 
+struct flagsettings {
+	unsigned int flags;
+	unsigned int mask;
+};
+
 static DEFINE_MUTEX(ddebug_lock);
 static LIST_HEAD(ddebug_tables);
 static int verbose;
@@ -142,7 +147,7 @@ static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
  * logs the changes.  Takes ddebug_lock.
  */
 static int ddebug_change(const struct ddebug_query *query,
-			unsigned int pflags, unsigned int mask)
+			 struct flagsettings *mods)
 {
 	int i;
 	struct ddebug_table *dt;
@@ -191,14 +196,14 @@ static int ddebug_change(const struct ddebug_query *query,
 
 			nfound++;
 
-			newflags = (dp->flags & mask) | pflags;
+			newflags = (dp->flags & mods->mask) | mods->flags;
 			if (newflags == dp->flags)
 				continue;
 #ifdef CONFIG_JUMP_LABEL
 			if (dp->flags & _DPRINTK_FLAGS_PRINT) {
-				if (!(pflags & _DPRINTK_FLAGS_PRINT))
+				if (!(mods->flags & _DPRINTK_FLAGS_PRINT))
 					static_branch_disable(&dp->key.dd_key_true);
-			} else if (pflags & _DPRINTK_FLAGS_PRINT)
+			} else if (mods->flags & _DPRINTK_FLAGS_PRINT)
 				static_branch_enable(&dp->key.dd_key_true);
 #endif
 			dp->flags = newflags;
@@ -414,14 +419,14 @@ static int ddebug_parse_query(char *words[], int nwords,
 	return 0;
 }
 
-static int ddebug_read_flags(const char *str, unsigned int *flags)
+static int ddebug_read_flags(const char *str, struct flagsettings *f)
 {
 	int i;
 
 	for (; *str ; ++str) {
 		for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
 			if (*str == opt_array[i].opt_char) {
-				*flags |= opt_array[i].flag;
+				f->flags |= opt_array[i].flag;
 				break;
 			}
 		}
@@ -430,7 +435,7 @@ static int ddebug_read_flags(const char *str, unsigned int *flags)
 			return -EINVAL;
 		}
 	}
-	vpr_info("flags=0x%x\n", *flags);
+	vpr_info("flags=0x%x mask=0x%x\n", f->flags, f->mask);
 	return 0;
 }
 
@@ -440,10 +445,8 @@ static int ddebug_read_flags(const char *str, unsigned int *flags)
  * flags fields of matched _ddebug's.  Returns 0 on success
  * or <0 on error.
  */
-static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
-			       unsigned int *maskp)
+static int ddebug_parse_flags(const char *str, struct flagsettings *mods)
 {
-	unsigned flags = 0;
 	int op;
 
 	switch (*str) {
@@ -458,31 +461,30 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
 	}
 	vpr_info("op='%c'\n", op);
 
-	if (ddebug_read_flags(str, &flags))
+	if (ddebug_read_flags(str, mods))
 		return -EINVAL;
 
-	/* calculate final *flagsp, *maskp according to mask and op */
+	/* calculate final flags, mask based upon op */
 	switch (op) {
 	case '=':
-		*maskp = 0;
-		*flagsp = flags;
+		mods->mask = 0;
 		break;
 	case '+':
-		*maskp = ~0U;
-		*flagsp = flags;
+		mods->mask = ~0U;
 		break;
 	case '-':
-		*maskp = ~flags;
-		*flagsp = 0;
+		mods->mask = ~mods->flags;
+		mods->flags = 0;
 		break;
 	}
-	vpr_info("*flagsp=0x%x *maskp=0x%x\n", *flagsp, *maskp);
+	vpr_info("*flagsp=0x%x *maskp=0x%x\n", mods->flags, mods->mask);
+
 	return 0;
 }
 
 static int ddebug_exec_query(char *query_string, const char *modname)
 {
-	unsigned int flags = 0, mask = 0;
+	struct flagsettings mods = {};
 	struct ddebug_query query;
 #define MAXWORDS 9
 	int nwords, nfound;
@@ -494,7 +496,7 @@ static int ddebug_exec_query(char *query_string, const char *modname)
 		return -EINVAL;
 	}
 	/* check flags 1st (last arg) so query is pairs of spec,val */
-	if (ddebug_parse_flags(words[nwords-1], &flags, &mask)) {
+	if (ddebug_parse_flags(words[nwords-1], &mods)) {
 		pr_err("flags parse failed\n");
 		return -EINVAL;
 	}
@@ -503,7 +505,7 @@ static int ddebug_exec_query(char *query_string, const char *modname)
 		return -EINVAL;
 	}
 	/* actually go and implement the change */
-	nfound = ddebug_change(&query, flags, mask);
+	nfound = ddebug_change(&query, &mods);
 	vpr_info_dq(&query, nfound ? "applied" : "no-match");
 
 	return nfound;
-- 
2.26.2