[RFC][PATCH v4 21/32] objtool: mcount: Only keep ELF file size

From: Matt Helsley <mhelsley@vmware.com>
To: <linux-kernel@vger.kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Sami Tolvanen <samitolvanen@google.com>,
	Julien Thierry <jthierry@redhat.com>,
	Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>,
	Matt Helsley <mhelsley@vmware.com>
Subject: [RFC][PATCH v4 21/32] objtool: mcount: Only keep ELF file size
Date: Tue, 2 Jun 2020 12:50:14 -0700	[thread overview]
Message-ID: <735f431969b4ffb21251ce7f491a262dff9293bc.1591125127.git.mhelsley@vmware.com> (raw)
In-Reply-To: <cover.1591125127.git.mhelsley@vmware.com>

Since we're no longer writing to the ELF file mapping and we're
not appending to it we don't need to keep more information from the
stat structure. At the same time we can give the smaller global
variable a better name.

Signed-off-by: Matt Helsley <mhelsley@vmware.com>
---
 tools/objtool/recordmcount.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/tools/objtool/recordmcount.c b/tools/objtool/recordmcount.c
index 6feb4e6b4113..85e95e1ea6f6 100644
--- a/tools/objtool/recordmcount.c
+++ b/tools/objtool/recordmcount.c
@@ -48,17 +48,17 @@
 static int fd_map;	/* File descriptor for file being modified. */
 static int mmap_failed; /* Boolean flag. */
 static char gpfx;	/* prefix for global symbol name (sometimes '_') */
-static struct stat sb;	/* Remember .st_size, etc. */
 static const char *altmcount;	/* alternate mcount symbol name */
 extern int warn_on_notrace_sect; /* warn when section has mcount not being recorded */
 static void *file_map;	/* pointer of the mapped file */
+static size_t file_map_size; /* original ELF file size */
 
 static struct elf *lf;
 
 static void mmap_cleanup(void)
 {
 	if (!mmap_failed)
-		munmap(file_map, sb.st_size);
+		munmap(file_map, file_map_size);
 	else
 		free(file_map);
 	file_map = NULL;
@@ -93,11 +93,13 @@ static void * umalloc(size_t size)
  */
 static void *mmap_file(char const *fname)
 {
+	struct stat sb;
+
 	/* Avoid problems if early cleanup() */
 	fd_map = -1;
 	mmap_failed = 1;
 	file_map = NULL;
-	sb.st_size = 0;
+	file_map_size = 0;
 
 	lf = elf_open_read(fname, O_RDWR);
 	if (!lf) {
@@ -129,6 +131,7 @@ static void *mmap_file(char const *fname)
 		}
 	} else
 		mmap_failed = 0;
+	file_map_size = sb.st_size;
 out:
 	fd_map = -1;
 
-- 
2.20.1

