user/sven/linux.git/lib/dynamic_debug.c, branch v3.4.40

dynamic_debug: process multiple debug-queries on a line

2012-01-24T20:50:36Z

Insert ddebug_exec_queries() in place of ddebug_exec_query(). It splits the query string on [;\n], and calls ddebug_exec_query() on each. All queries are processed independent of errors, allowing a query to fail, for example when a module is not installed. Empty lines and comments are skipped. Errors are counted, and the last error seen (negative) or the number of callsites found (0 or positive) is returned. Return code checks are altered accordingly. With this, multiple queries can be given in ddebug_query, allowing more selective enabling of callsites. As a side effect, a set of commands can be batched in: cat cmd-file > $DBGMT/dynamic_debug/control We dont want a ddebug_query syntax error to kill the dynamic debug facility, so dynamic_debug_init() zeros ddebug_exec_queries()'s return code after logging the appropriate message, so that ddebug tables are preserved and $DBGMT/dynamic_debug/control file is created. This would be appropriate even without accepting multiple queries. This patch also alters ddebug_change() to return number of callsites matched (which typically is the same as number of callsites changed). ddebug_exec_query() also returns the number found, or a negative value if theres a parse error on the query. Splitting on [;\n] prevents their use in format-specs, but selecting callsites on punctuation is brittle anyway, meaningful and selective substrings are more typical. Note: splitting queries on ';' before handling trailing #comments means that a ';' also terminates a comment, and text after the ';' is treated as another query. This trailing query will almost certainly result in a parse error and thus have no effect other than the error message. The double corner case with unexpected results is: ddebug_query="func foo +p # enable foo ; +p" Signed-off-by: Jim Cromie Signed-off-by: Jason Baron Signed-off-by: Greg Kroah-Hartman

dynamic_debug: factor vpr_info_dq out of ddebug_parse_query

2012-01-24T20:50:36Z

Factor pr_info(query) out of ddebug_parse_query, into vpr_info_dq(), for reuse later. Also change the printed labels: file, func to agree with the query-spec keywords accepted in the control file. Pass "" when string is null, to avoid "(null)" output from sprintf. For format print, use precision to skip last char, assuming its '\n', no great harm if not, its a debug msg. Signed-off-by: Jim Cromie Signed-off-by: Jason Baron Signed-off-by: Greg Kroah-Hartman

dynamic_debug: add trim_prefix() to provide source-root relative paths

2012-01-24T20:48:55Z

trim_prefix(path) skips past the absolute source path root, and returns the pointer to the relative path from there. It is used to shorten the displayed path in $DBGMT/dynamic_debug/control via ddebug_proc_show(), and in ddebug_change() to allow relative filenames to be used in applied queries. For example: ~# echo file kernel/freezer.c +p > $DBGMT/dynamic_debug/control kernel/freezer.c:128 [freezer]cancel_freezing p " clean up: %s\012" trim_prefix(path) insures common prefix before trimming it, so out-of-tree module paths are shown as full absolute paths. Signed-off-by: Jim Cromie Signed-off-by: Jason Baron Signed-off-by: Greg Kroah-Hartman

dynamic_debug: enlarge command/query write buffer

2012-01-24T20:48:55Z

Current query write buffer is 256 bytes, on stack. In comparison, the ddebug_query boot-arg is 1024. Allocate the buffer off heap, and enlarge it to 4096 bytes, big enough for ~100 queries (at 40 bytes each), and error out if not. This makes it play nicely with large query sets (to be added later). The buffer should be enough for most uses, and others should probably be split into subsets. [jbaron@redhat.com: changed USER_BUF_PAGE from 4095 -> 4096 ] Signed-off-by: Jim Cromie Signed-off-by: Jason Baron Signed-off-by: Greg Kroah-Hartman

dynamic_debug: chop off comments in ddebug_tokenize

2012-01-24T20:48:54Z

If a token begins with #, the remainder of query string is a comment, so drop it. Doing it here avoids '#' in quoted strings. Signed-off-by: Jim Cromie Signed-off-by: Jason Baron Signed-off-by: Greg Kroah-Hartman

dynamic_debug: early return if _ddebug table is empty

2012-01-24T20:48:54Z

If _ddebug table is empty (in a CONFIG_DYNAMIC_DEBUG build this shouldn't happen), then warn (error?) and return early. This skips empty table scan and parsing of setup-string, including the pr_info call noting the parse. By inspection, copy return-code handling from 1st ddebug_add_module() callsite to 2nd. Signed-off-by: Jim Cromie Signed-off-by: Jason Baron Signed-off-by: Greg Kroah-Hartman

dynamic_debug: tighten up error checking on debug queries

2012-01-24T20:48:53Z

Issue error when a match-spec is given multiple times in a rule. Previous code kept last one, but was silent about it. Docs imply only one is allowed by saying match-specs are ANDed together, given that module M cannot match both A and B. Also error when last_line < 1st_line. Signed-off-by: Jim Cromie Signed-off-by: Jason Baron Signed-off-by: Greg Kroah-Hartman

dynamic_debug: describe_flags with '=[pmflt_]*'

2012-01-24T20:48:52Z

Change describe_flags() to emit '=[pmflt_]+' for current callsite flags, or just '=_' when they're disabled. Having '=' in output allows a more selective grep expression; in contrast '-' may appear in filenames, line-ranges, and format-strings. '=' also has better mnemonics, saying; "the current setting is equal to ". This allows grep "=_" /dynamic_debug/control to see disabled callsites while avoiding the many occurrences of " = " seen in format strings. Enlarge flagsbufs to handle additional flag char, and alter ddebug_parse_flags() to allow flags=0, so that user can turn off all debug flags via: ~# echo =_ > /dynamic_debug/control Signed-off-by: Jim Cromie Signed-off-by: Jason Baron Signed-off-by: Greg Kroah-Hartman

dynamic_debug: drop explicit !=NULL checks

2012-01-24T20:46:46Z

Convert 'if (x !=NULL)' checks into 'if (x)'. Signed-off-by: Jim Cromie Signed-off-by: Jason Baron Signed-off-by: Greg Kroah-Hartman

dynamic_debug: pr_err() call should not depend upon verbosity

2012-01-24T20:46:45Z

Issue keyword/parsing errors even w/o verbose set; uncover otherwize mysterious non-functionality. Signed-off-by: Jim Cromie Signed-off-by: Jason Baron Signed-off-by: Greg Kroah-Hartman