linux-kernel - [RFC][PATCH v5 24/51] objtool: mcount: Only keep ELF file size

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Date:   Thu, 18 Jun 2020 13:38:10 -0700
From:   Matt Helsley <mhelsley@...are.com>
To:     <linux-kernel@...r.kernel.org>
CC:     Josh Poimboeuf <jpoimboe@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Julien Thierry <jthierry@...hat.com>,
        Kamalesh Babulal <kamalesh@...ux.vnet.ibm.com>,
        Matt Helsley <mhelsley@...are.com>
Subject: [RFC][PATCH v5 24/51] objtool: mcount: Only keep ELF file size

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@...are.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 29f299e5bb52..aa35173de3d9 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