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Tue, 02 Jun 2026 15:48:55 -0700 (PDT) Received: from [172.16.188.153] ([213.181.114.83]) by smtp.googlemail.com with ESMTPSA id ffacd0b85a97d-4601f2f2710sm1999791f8f.14.2026.06.02.15.48.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Jun 2026 15:48:55 -0700 (PDT) From: Jim Cromie Date: Tue, 02 Jun 2026 22:48:13 +0000 Subject: [PATCH v4 16/25] dyndbg: replace classmap list with an array-slice Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260602-dd-maint-2-v4-16-19a1445585a8@gmail.com> References: <20260602-dd-maint-2-v4-0-19a1445585a8@gmail.com> In-Reply-To: <20260602-dd-maint-2-v4-0-19a1445585a8@gmail.com> To: Jonathan Corbet , Shuah Khan , Arnd Bergmann , Jason Baron , Luis Chamberlain , Petr Pavlu , Daniel Gomez , Sami Tolvanen , Aaron Tomlin , Andrew Morton , Shuah Khan , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-modules@vger.kernel.org, linux-kselftest@vger.kernel.org, dri-devel@lists.freedesktop.org, Jim Cromie , Louis Chauvet X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1780440488; l=6628; i=jim.cromie@gmail.com; s=20260203; h=from:subject:message-id; bh=vk7X0gvsN/pluaAvdCwu1r3tDscy4XY8tNtE6cf5F9I=; b=bCI/agdbnZfA3Wzw5qVqSADM6r8GwdbtcnFMRi0CNQPZ/gF8oSeOh7PBSsTT4gYkukj4ZciSn PzY23Imk9K6BUlTS/Vbn0KVKWXv5pDePzLiGIjF68olaw0ESDwOuime X-Developer-Key: i=jim.cromie@gmail.com; a=ed25519; pk=C6E5ODlPQo7ZBynATXH9wg7K6HxP0pIXyf4s38Qw0XE= Classmaps are stored in an elf section/array, but currently are individually list-linked onto dyndbg's per-module ddebug_table for operation. This is unnecessary. Just like dyndbg's descriptors, classes are packed in compile order; so even with many builtin modules employing multiple classmaps, each modules' maps are packed contiguously, and can be treated as a array-start-address & array-length. So this drops the whole list building operation done in ddebug_attach_module_classes(), and removes the list-head members of the classmap structs. The "select-by-modname" condition is reused to find the start,end of the subrange of classmaps belonging to the module. NOTES: There are multiple modules named "main" but thats an artifact of how KBUILD_MODNAME gets its value, and none of those repeats are contiguous. The legacy code segmenting the builtin descriptors depends upon this, we are "reusing" that dependency. The "filter-by-modname" on classmaps should really be done in ddebug_add_module(1); ie closer to dynamic_debug_init(2), which already splits up pr-debug descriptors into subranges by modname, then calls (1) on each. (2) knows nothing of classmaps currently, and doesn't need to. Signed-off-by: Jim Cromie Reviewed-by: Louis Chauvet --- v2: RvB after SoB --- include/linux/dynamic_debug.h | 1 - lib/dynamic_debug.c | 65 +++++++++++++++++++++++-------------------- 2 files changed, 35 insertions(+), 31 deletions(-) diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h index 867e3978675f..0443781ed95b 100644 --- a/include/linux/dynamic_debug.h +++ b/include/linux/dynamic_debug.h @@ -73,7 +73,6 @@ enum ddebug_class_map_type { }; struct ddebug_class_map { - struct list_head link; struct module *mod; const char *mod_name; /* needed for builtins */ const char **class_names; diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 9bd521651c48..b8a494835ef5 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -45,10 +45,11 @@ extern struct ddebug_class_map __start___dyndbg_classes[]; extern struct ddebug_class_map __stop___dyndbg_classes[]; struct ddebug_table { - struct list_head link, maps; + struct list_head link; const char *mod_name; - unsigned int num_ddebugs; struct _ddebug *ddebugs; + struct ddebug_class_map *classes; + unsigned int num_ddebugs, num_classes; }; struct ddebug_query { @@ -149,12 +150,13 @@ static void v3pr_info_dq(const struct ddebug_query *query, const char *msg) } static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table const *dt, - const char *class_string, int *class_id) + const char *class_string, + int *class_id) { struct ddebug_class_map *map; - int idx; + int i, idx; - list_for_each_entry(map, &dt->maps, link) { + for (map = dt->classes, i = 0; i < dt->num_classes; i++, map++) { idx = match_string(map->class_names, map->length, class_string); if (idx >= 0) { *class_id = idx + map->base; @@ -165,7 +167,6 @@ static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table cons return NULL; } -#define __outvar /* filled by callee */ /* * Search the tables for _ddebug's which match the given `query' and * apply the `flags' and `mask' to them. Returns number of matching @@ -227,7 +228,7 @@ static int ddebug_change(const struct ddebug_query *query, unsigned int nfound = 0; struct flagsbuf fbuf, nbuf; struct ddebug_class_map *map = NULL; - int __outvar valid_class; + int valid_class; /* search for matching ddebugs */ mutex_lock(&ddebug_lock); @@ -1064,9 +1065,10 @@ static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos) static const char *ddebug_class_name(struct ddebug_iter *iter, struct _ddebug *dp) { - struct ddebug_class_map *map; + struct ddebug_class_map *map = iter->table->classes; + int i, nc = iter->table->num_classes; - list_for_each_entry(map, &iter->table->maps, link) + for (i = 0; i < nc; i++, map++) if (class_in_range(dp->class_id, map)) return map->class_names[dp->class_id - map->base]; @@ -1150,30 +1152,34 @@ static const struct proc_ops proc_fops = { .proc_write = ddebug_proc_write }; -static void ddebug_attach_module_classes(struct ddebug_table *dt, - struct ddebug_class_map *classes, - int num_classes) +static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug_info *di) { struct ddebug_class_map *cm; - int i, j, ct = 0; + int i, nc = 0; - for (cm = classes, i = 0; i < num_classes; i++, cm++) { + /* + * Find this module's classmaps in a subrange/wholerange of + * the builtin/modular classmap vector/section. Save the start + * and length of the subrange at its edges. + */ + for (cm = di->classes, i = 0; i < di->num_classes; i++, cm++) { if (!strcmp(cm->mod_name, dt->mod_name)) { - - v2pr_info("class[%d]: module:%s base:%d len:%d ty:%d\n", i, - cm->mod_name, cm->base, cm->length, cm->map_type); - - for (j = 0; j < cm->length; j++) - v3pr_info(" %d: %d %s\n", j + cm->base, j, - cm->class_names[j]); - - list_add(&cm->link, &dt->maps); - ct++; + if (!nc) { + v2pr_info("start subrange, class[%d]: module:%s base:%d len:%d ty:%d\n", + i, cm->mod_name, cm->base, cm->length, cm->map_type); + dt->classes = cm; + } + nc++; + } else if (nc) { + /* end of matching classmaps */ + break; } } - if (ct) - vpr_info("module:%s attached %d classes\n", dt->mod_name, ct); + if (nc) { + dt->num_classes = nc; + vpr_info("module:%s attached %d classes\n", dt->mod_name, nc); + } } /* @@ -1205,10 +1211,9 @@ static int ddebug_add_module(struct _ddebug_info *di, const char *modname) dt->num_ddebugs = di->num_descs; INIT_LIST_HEAD(&dt->link); - INIT_LIST_HEAD(&dt->maps); if (di->classes && di->num_classes) - ddebug_attach_module_classes(dt, di->classes, di->num_classes); + ddebug_attach_module_classes(dt, di); mutex_lock(&ddebug_lock); list_add_tail(&dt->link, &ddebug_tables); @@ -1321,8 +1326,8 @@ static void ddebug_remove_all_tables(void) mutex_lock(&ddebug_lock); while (!list_empty(&ddebug_tables)) { struct ddebug_table *dt = list_entry(ddebug_tables.next, - struct ddebug_table, - link); + struct ddebug_table, + link); ddebug_table_free(dt); } mutex_unlock(&ddebug_lock); -- 2.54.0