[RFC PATCH v6 30/34] dyndbg: split/copy ._index into 2 new fields: ._back, ._map

Jim Cromie
2021-05-29T20:03:47Z

In order to do:
__dyndbgs[-N].site->__dyndbg_sites[N]

._index had 2 jobs:
provide index back to __dyndbgs[0]
provide index out to __dyndbg_sites[N]

So rename ._index to ._back & ._map, adjust ddebug_add_module()
to init both fields identically, and replace other ._index's
with the "correct" replacement.

NOTES:

._map is a better name better than ._out. Since ._map is a
separate field, it can map arbitrarily. It now maps ddebugs->sites
1->1, but it can/will-soon map N->1; all a function's pr_debugs
will share a single _ddebug_site, and we can reclaim redundant rows.

The "correct" choice of ._map/._back cannot be tested properly now,
since ._map == ._back. Once N->1 is done, we can re-define SITE_CHK
and validate (or correct) the ._map/._back choices made here.

No functional changes.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
include/linux/dynamic_debug.h | 6 ++++--
lib/dynamic_debug.c | 35 ++++++++++++++++++-----------------
2 files changed, 22 insertions(+), 19 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index b2189ff94fda..fe70dda704d2 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -51,7 +51,8 @@ struct _ddebug {
/* format is always needed, lineno shares word with flags */
const char *format;
const unsigned lineno:18;
- unsigned _index:14;
+ unsigned _back:14;
+ unsigned _map:14;
/*
* The flags field controls the behaviour at the callsite.
* The bits here are changed dynamically when the user
@@ -95,7 +96,8 @@ union _ddebug_header {
union _ddebug_site_header *site;
const char *format;
const unsigned lineno:18;
- unsigned _index:14;
+ unsigned _back:14;
+ unsigned _map:14;
unsigned int flags:8;
};
};
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 0e2e082b487b..524303a04462 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -148,39 +148,39 @@ static void vpr_info_dq(const struct ddebug_query *query, const char *msg)

static struct _ddebug_site *ddebug_site_get(struct _ddebug *dp)
{
- union _ddebug_header *dh = (union _ddebug_header *) (dp - dp->_index);
+ union _ddebug_header *dh = (union _ddebug_header *) (dp - dp->_back);

if (!is_dyndbg_header_pair(dh, dh->site))
- v3pr_info("get: header fail on %d-%d\n", dp->_index, dp->lineno);
+ v3pr_info("get: header fail on %d-%d\n", dp->_back, dp->lineno);

#ifdef SITE_CHK
if (dp >= __start___dyndbg && dp < __stop___dyndbg) {

v5pr_info("get: %s is builtin: %d %s:%s:%d\n",
- dh->site[dp->_index].modname, dp->_index,
- dh->site[dp->_index].filename,
- dh->site[dp->_index].function, dp->lineno);
+ dh->site[dp->_map].modname, dp->_back,
+ dh->site[dp->_map].filename,
+ dh->site[dp->_map].function, dp->lineno);

- BUG_ON(dp != &__start___dyndbg[dp->_index]);
+ BUG_ON(dp != &__start___dyndbg[dp->_back]);

- BUG_ON(!(dp->_index == (dp - dh) &&
- dp->_index == (dp - __start___dyndbg) &&
- dp->_index == (&__start___dyndbg_sites[dp->_index]
+ BUG_ON(!(dp->_back == (dp - dh) &&
+ dp->_back == (dp - __start___dyndbg) &&
+ dp->_back == (&__start___dyndbg_sites[dp->_back]
- &__start___dyndbg_sites[0])));
if (dp->site)
- BUG_ON(&__start___dyndbg_sites[dp->_index] != dp->site);
+ BUG_ON(&__start___dyndbg_sites[dp->_map] != dp->site);
} else {
v4pr_info("get: %s is loaded: %d %s:%s:%d\n",
- dh->site[dp->_index].modname, dp->_index,
- dh->site[dp->_index].filename,
- dh->site[dp->_index].function, dp->lineno);
+ dh->site[dp->_map].modname, dp->_back,
+ dh->site[dp->_map].filename,
+ dh->site[dp->_map].function, dp->lineno);
}
if (dp->site)
- BUG_ON(&dh->site[dp->_index] != dp->site);
+ BUG_ON(&dh->site[dp->_map] != dp->site);

return dp->site;
#else
- return (struct _ddebug_site *) &dh->site[dp->_index];
+ return (struct _ddebug_site *) &dh->site[dp->_map];
#endif
}
static inline void ddebug_site_put(struct _ddebug *dp)
@@ -1108,8 +1108,9 @@ static int __ddebug_add_module(struct _ddebug *tab, struct _ddebug_site *sites,
dt->sites = sites;

for (i = 0; i < numdbgs; i++) {
- tab[i]._index = base + i;
- v3pr_info(" %d %d %s.%s.%d\n", i, tab[i]._index,
+ tab[i]._back = base + i;
+ tab[i]._map = base + i;
+ v3pr_info(" %d %d %d %s.%s.%d\n", i, tab[i]._back, tab[i]._map,
modname, sites[i].function, tab[i].lineno);
}

--
2.31.1