linux-kernel - [PATCH v2 04/20] dyndbg: make ddebug_apply_class

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Message-Id: <20230113193016.749791-5-jim.cromie@gmail.com>
Date:   Fri, 13 Jan 2023 12:30:00 -0700
From:   Jim Cromie <jim.cromie@...il.com>
To:     linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        amd-gfx@...ts.freedesktop.org, intel-gvt-dev@...ts.freedesktop.org,
        intel-gfx@...ts.freedesktop.org
Cc:     jani.nikula@...el.com, ville.syrjala@...ux.intel.com,
        daniel.vetter@...ll.ch, seanpaul@...omium.org, robdclark@...il.com,
        jbaron@...mai.com, gregkh@...uxfoundation.org,
        Jim Cromie <jim.cromie@...il.com>
Subject: [PATCH v2 04/20] dyndbg: make ddebug_apply_class_bitmap more selective

ddebug_apply_class_bitmap() currently applies the class settings to
all modules, by calling ddebug_exec_queries(query, NULL), where NULL
is wildcard ("*" does the same).  Make it more selective, by adding
query_module param, and passing it into ddebug_exec_queries, instead
of the NULL.

This allows its more selective use later; for propagating drm.debug
settings to dependent modules when/just-after they load.  Doing this
propagation with "*" is fine, but would match with all previously
loaded modules, creating more dynamic_debug.verbose=3 logging
activity, and obscuring the actual changes.

No functional change.

Signed-off-by: Jim Cromie <jim.cromie@...il.com>
---

after `modprobe i915`, heres the module dependencies,
though not all on drm.debug.

bash-5.2# lsmod
Module                  Size  Used by
i915                 3133440  0
drm_buddy              20480  1 i915
ttm                    90112  1 i915
i2c_algo_bit           16384  1 i915
video                  61440  1 i915
wmi                    32768  1 video
drm_display_helper    200704  1 i915
drm_kms_helper        208896  2 drm_display_helper,i915
drm                   606208  5 drm_kms_helper,drm_display_helper,drm_buddy,i915,ttm
cec                    57344  2 drm_display_helper,i915
---
 lib/dynamic_debug.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 823190094350..943e0597ecd4 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -600,7 +600,8 @@ static int ddebug_exec_queries(char *query, const char *modname)
 
 /* apply a new bitmap to the sys-knob's current bit-state */
 static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
-				     unsigned long *new_bits, unsigned long *old_bits)
+				     unsigned long *new_bits, unsigned long *old_bits,
+				     const char *query_modname)
 {
 #define QUERY_SIZE 128
 	char query[QUERY_SIZE];
@@ -608,7 +609,8 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 	int matches = 0;
 	int bi, ct;
 
-	v2pr_info("apply: 0x%lx to: 0x%lx\n", *new_bits, *old_bits);
+	v2pr_info("apply bitmap: 0x%lx to: 0x%lx for %s\n", *new_bits, *old_bits,
+		  query_modname ?: "");
 
 	for (bi = 0; bi < map->length; bi++) {
 		if (test_bit(bi, new_bits) == test_bit(bi, old_bits))
@@ -617,12 +619,15 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 		snprintf(query, QUERY_SIZE, "class %s %c%s", map->class_names[bi],
 			 test_bit(bi, new_bits) ? '+' : '-', dcp->flags);
 
-		ct = ddebug_exec_queries(query, NULL);
+		ct = ddebug_exec_queries(query, query_modname);
 		matches += ct;
 
 		v2pr_info("bit_%d: %d matches on class: %s -> 0x%lx\n", bi,
 			  ct, map->class_names[bi], *new_bits);
 	}
+	v2pr_info("applied bitmap: 0x%lx to: 0x%lx for %s\n", *new_bits, *old_bits,
+		  query_modname ?: "");
+
 	return matches;
 }
 
@@ -678,7 +683,7 @@ static int param_set_dyndbg_classnames(const char *instr, const struct kernel_pa
 				continue;
 			}
 			curr_bits ^= BIT(cls_id);
-			totct += ddebug_apply_class_bitmap(dcp, &curr_bits, dcp->bits);
+			totct += ddebug_apply_class_bitmap(dcp, &curr_bits, dcp->bits, NULL);
 			*dcp->bits = curr_bits;
 			v2pr_info("%s: changed bit %d:%s\n", KP_NAME(kp), cls_id,
 				  map->class_names[cls_id]);
@@ -688,7 +693,7 @@ static int param_set_dyndbg_classnames(const char *instr, const struct kernel_pa
 			old_bits = CLASSMAP_BITMASK(*dcp->lvl);
 			curr_bits = CLASSMAP_BITMASK(cls_id + (wanted ? 1 : 0 ));
 
-			totct += ddebug_apply_class_bitmap(dcp, &curr_bits, &old_bits);
+			totct += ddebug_apply_class_bitmap(dcp, &curr_bits, &old_bits, NULL);
 			*dcp->lvl = (cls_id + (wanted ? 1 : 0));
 			v2pr_info("%s: changed bit-%d: \"%s\" %lx->%lx\n", KP_NAME(kp), cls_id,
 				  map->class_names[cls_id], old_bits, curr_bits);
@@ -751,7 +756,7 @@ int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
 			inrep &= CLASSMAP_BITMASK(map->length);
 		}
 		v2pr_info("bits:%lx > %s\n", inrep, KP_NAME(kp));
-		totct += ddebug_apply_class_bitmap(dcp, &inrep, dcp->bits);
+		totct += ddebug_apply_class_bitmap(dcp, &inrep, dcp->bits, NULL);
 		*dcp->bits = inrep;
 		break;
 	case DD_CLASS_TYPE_LEVEL_NUM:
@@ -764,7 +769,7 @@ int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
 		old_bits = CLASSMAP_BITMASK(*dcp->lvl);
 		new_bits = CLASSMAP_BITMASK(inrep);
 		v2pr_info("lvl:%ld bits:0x%lx > %s\n", inrep, new_bits, KP_NAME(kp));
-		totct += ddebug_apply_class_bitmap(dcp, &new_bits, &old_bits);
+		totct += ddebug_apply_class_bitmap(dcp, &new_bits, &old_bits, NULL);
 		*dcp->lvl = inrep;
 		break;
 	default:
-- 
2.39.0