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Date: Sun, 19 Jul 2020 17:10:55 -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 v5 15/18] dyndbg: combine flags & mask into a struct, simplify with it
flags & mask are used together everywhere, and are passed around
together between multiple functions; they belong together in a struct,
call that struct flag_settings.
Use struct flag_settings to rework 3 functions:
- ddebug_exec_query - declares query and flag-settings,
calls other 2, passing flags
- ddebug_parse_flags - fills flag_settings and returns
- ddebug_change - test all callsites against query,
modify passing sites.
benefits:
- bit-banging always needs flags & mask, best together.
- simpler function signatures
- 1 less parameter, less stack overhead
no functional changes
Signed-off-by: Jim Cromie <jim.cromie@...il.com>
---
lib/dynamic_debug.c | 45 ++++++++++++++++++++++++---------------------
1 file changed, 24 insertions(+), 21 deletions(-)
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index fad6c34c930d..c983049e986d 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -62,6 +62,11 @@ struct ddebug_iter {
unsigned int idx;
};
+struct flag_settings {
+ unsigned int flags;
+ unsigned int mask;
+};
+
static DEFINE_MUTEX(ddebug_lock);
static LIST_HEAD(ddebug_tables);
static int verbose;
@@ -141,7 +146,7 @@ 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 flags, unsigned int mask)
+ struct flag_settings *modifiers)
{
int i;
struct ddebug_table *dt;
@@ -190,14 +195,14 @@ static int ddebug_change(const struct ddebug_query *query,
nfound++;
- newflags = (dp->flags & mask) | flags;
+ newflags = (dp->flags & modifiers->mask) | modifiers->flags;
if (newflags == dp->flags)
continue;
#ifdef CONFIG_JUMP_LABEL
if (dp->flags & _DPRINTK_FLAGS_PRINT) {
- if (!(flags & _DPRINTK_FLAGS_PRINT))
+ if (!(modifiers->flags & _DPRINTK_FLAGS_PRINT))
static_branch_disable(&dp->key.dd_key_true);
- } else if (flags & _DPRINTK_FLAGS_PRINT)
+ } else if (modifiers->flags & _DPRINTK_FLAGS_PRINT)
static_branch_enable(&dp->key.dd_key_true);
#endif
dp->flags = newflags;
@@ -431,11 +436,9 @@ static int ddebug_parse_query(char *words[], int nwords,
* 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 flag_settings *modifiers)
{
- unsigned flags = 0;
- int op = '=', i;
+ int op, i;
switch (*str) {
case '+':
@@ -452,7 +455,7 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
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;
+ modifiers->flags |= opt_array[i].flag;
break;
}
}
@@ -461,30 +464,30 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
return -EINVAL;
}
}
- vpr_info("flags=0x%x\n", flags);
+ vpr_info("flags=0x%x\n", modifiers->flags);
- /* calculate final *flagsp, *maskp according to mask and op */
+ /* calculate final flags, mask based upon op */
switch (op) {
case '=':
- *maskp = 0;
- *flagsp = flags;
+ /* modifiers->flags already set */
+ modifiers->mask = 0;
break;
case '+':
- *maskp = ~0U;
- *flagsp = flags;
+ modifiers->mask = ~0U;
break;
case '-':
- *maskp = ~flags;
- *flagsp = 0;
+ modifiers->mask = ~modifiers->flags;
+ modifiers->flags = 0;
break;
}
- vpr_info("*flagsp=0x%x *maskp=0x%x\n", *flagsp, *maskp);
+ vpr_info("*flagsp=0x%x *maskp=0x%x\n", modifiers->flags, modifiers->mask);
+
return 0;
}
static int ddebug_exec_query(char *query_string, const char *modname)
{
- unsigned int flags = 0, mask = 0;
+ struct flag_settings modifiers = {};
struct ddebug_query query = {};
#define MAXWORDS 9
int nwords, nfound;
@@ -496,7 +499,7 @@ 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], &modifiers)) {
pr_err("flags parse failed\n");
return -EINVAL;
}
@@ -505,7 +508,7 @@ 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, &modifiers);
vpr_info_dq(&query, nfound ? "applied" : "no-match");
return nfound;
--
2.26.2
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