From c7b8041928565786fc58fd20e80b278cc877bef4 Mon Sep 17 00:00:00 2001 From: Jim Cromie Date: Thu, 5 Sep 2019 00:25:34 -0600 Subject: [PATCH 1/2] dynamic_debug: drop obsolete trim_prefix Some time ago, __FILE__ on gcc kernel builds changed from a full path to a source-root-relative path. Presumably this happened after 2b6783191da7 dynamic_debug: add trim_prefix() to provide source-root relative paths That patch added trim_prefix() to improve readability by shortening lines in control file, in vpr_info output, and to accept relative filenames in ddebug_query(), improving ease of use. At any rate, __FILE__ now yields source-root-relative names, so trim_prefix() is worse than obsolete; it has code to skip common prefixes where used (see above), which can hide bugs in adaptations for 2 kinds of uses. Moreover, that code uses __FILE__ and was thus unnaffected by the behavior change. Now it just obfuscates. So remove fn, and 3 uses. The query case deserves a closer look. Per Documentation/admin-guide/dynamic-debug-howto.rst: file The given string is compared against either the full pathname, the src-root relative pathname, or the basename of the source file of each callsite. Examples:: file svcsock.c file kernel/freezer.c file /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svcsock.c The 3rd use was the original form, and the least useful (except for copy-paste of full-paths). It is not properly supported by current code, as __FILE__ has already stripped ~/projects/linux.git/, defeating the prefix-skip code on a "filename " search. Since it already broken, lets just remove it. wildcard match added since should help ease transition. --- lib/dynamic_debug.c | 19 +++---------------- 1 file changed, 3 insertions(+), 16 deletions(-) diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index c60409138e13..ba35199edd9c 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -67,17 +67,6 @@ static LIST_HEAD(ddebug_tables); static int verbose; module_param(verbose, int, 0644); -/* Return the path relative to source root */ -static inline const char *trim_prefix(const char *path) -{ - int skip = strlen(__FILE__) - strlen("lib/dynamic_debug.c"); - - if (strncmp(path, __FILE__, skip)) - skip = 0; /* prefix mismatch, don't skip */ - - return path + skip; -} - static struct { unsigned flag:8; char opt_char; } opt_array[] = { { _DPRINTK_FLAGS_PRINT, 'p' }, { _DPRINTK_FLAGS_INCL_MODNAME, 'm' }, @@ -162,9 +151,7 @@ static int ddebug_change(const struct ddebug_query *query, if (query->filename && !match_wildcard(query->filename, dp->filename) && !match_wildcard(query->filename, - kbasename(dp->filename)) && - !match_wildcard(query->filename, - trim_prefix(dp->filename))) + kbasename(dp->filename))) continue; /* match against the function */ @@ -199,7 +186,7 @@ static int ddebug_change(const struct ddebug_query *query, #endif dp->flags = newflags; vpr_info("changed %s:%d [%s]%s =%s\n", - trim_prefix(dp->filename), dp->lineno, + dp->filename, dp->lineno, dt->mod_name, dp->function, ddebug_describe_flags(dp, flagbuf, sizeof(flagbuf))); @@ -827,7 +814,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p) } seq_printf(m, "%s:%u [%s]%s =%s \"", - trim_prefix(dp->filename), dp->lineno, + dp->filename, dp->lineno, iter->table->mod_name, dp->function, ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf))); seq_escape(m, dp->format, "\t\r\n\""); -- 2.21.0