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From:   Jim Cromie <jim.cromie@gmail.com>
To:     jbaron@akamai.com, linux-kernel@vger.kernel.org
Cc:     linux@rasmusvillemoes.dk, greg@kroah.com,
        Jim Cromie <jim.cromie@gmail.com>,
        clang-built-linux@googlegroups.com,
        Jonathan Corbet <corbet@lwn.net>,
        Randy Dunlap <rdunlap@infradead.org>, linux-doc@vger.kernel.org
Subject: [PATCH 01/16] dyndbg: drop trim_prefix, obsoleted by __FILE__s relative path
Date:   Tue, 29 Oct 2019 14:00:00 -0600
Message-Id: <20191029200001.9640-1-jim.cromie@gmail.com>
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Regarding:
commit 2b6783191da7 ("dynamic_debug: add trim_prefix() to provide source-root relative paths")
commit a73619a845d5 ("kbuild: use -fmacro-prefix-map to make __FILE__ a relative path")

2nd commit broke dynamic-debug's "file $fullpath" query form, but
nobody noticed because 1st commit trimmed prefixes from control-file
output, so the click-copy-pasting of fullpaths into new queries had
ceased; that query form became unused.

So remove the function and callers; its purpose was to strip the
prefix from __FILE__, which is now gone.  Further, there is no loss of
query selectivity, and no real value in iteratively trimming ^/\w+
prefix and testing for a match.

Also drop "file $fullpath" from docs, and tweak example to cite column
1 of control-file as valid "file $input".

cc: clang-built-linux@googlegroups.com

I built one clang-kernel a while ago to see if this patch broke
things, it did not, but I may have messed up something.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 .../admin-guide/dynamic-debug-howto.rst       | 19 +++++++++----------
 lib/dynamic_debug.c                           | 19 +++----------------
 2 files changed, 12 insertions(+), 26 deletions(-)

diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
index 252e5ef324e5..e011f8907116 100644
--- a/Documentation/admin-guide/dynamic-debug-howto.rst
+++ b/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -62,10 +62,10 @@ statements via::
 
   nullarbor:~ # cat <debugfs>/dynamic_debug/control
   # filename:lineno [module]function flags format
-  /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:323 [svcxprt_rdma]svc_rdma_cleanup =_ "SVCRDMA Module Removed, deregister RPC RDMA transport\012"
-  /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:341 [svcxprt_rdma]svc_rdma_init =_ "\011max_inline       : %d\012"
-  /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:340 [svcxprt_rdma]svc_rdma_init =_ "\011sq_depth         : %d\012"
-  /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:338 [svcxprt_rdma]svc_rdma_init =_ "\011max_requests     : %d\012"
+  net/sunrpc/svc_rdma.c:323 [svcxprt_rdma]svc_rdma_cleanup =_ "SVCRDMA Module Removed, deregister RPC RDMA transport\012"
+  net/sunrpc/svc_rdma.c:341 [svcxprt_rdma]svc_rdma_init =_ "\011max_inline       : %d\012"
+  net/sunrpc/svc_rdma.c:340 [svcxprt_rdma]svc_rdma_init =_ "\011sq_depth         : %d\012"
+  net/sunrpc/svc_rdma.c:338 [svcxprt_rdma]svc_rdma_init =_ "\011max_requests     : %d\012"
   ...
 
 
@@ -85,7 +85,7 @@ the debug statement callsites with any non-default flags::
 
   nullarbor:~ # awk '$3 != "=_"' <debugfs>/dynamic_debug/control
   # filename:lineno [module]function flags format
-  /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svcsock.c:1603 [sunrpc]svc_send p "svc_process: st_sendto returned %d\012"
+  net/sunrpc/svcsock.c:1603 [sunrpc]svc_send p "svc_process: st_sendto returned %d\012"
 
 Command Language Reference
 ==========================
@@ -158,13 +158,12 @@ func
 	func svc_tcp_accept
 
 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::
+    The given string is compared against either 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
+	file kernel/freezer.c	# ie column 1 of control file
 
 module
     The given string is compared against the module name
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