From d4144ea6e7cc307e84cd9ca227df7b04a54a2365 Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Thu, 16 Apr 2015 12:49:18 -0700 Subject: tomoyo: reduce mmap_sem hold for mm->exe_file The mm->exe_file is currently serialized with mmap_sem (shared) in order to both safely (1) read the file and (2) compute the realpath by calling tomoyo_realpath_from_path, making it an absolute overkill. Good users will, on the other hand, make use of the more standard get_mm_exe_file(), requiring only holding the mmap_sem to read the value, and relying on reference [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Davidlohr Bueso Acked-by: Tetsuo Handa Cc: James Morris Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- security/tomoyo/util.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) (limited to 'security') diff --git a/security/tomoyo/util.c b/security/tomoyo/util.c index 2952ba576fb9..b974a6997d7f 100644 --- a/security/tomoyo/util.c +++ b/security/tomoyo/util.c @@ -948,15 +948,18 @@ bool tomoyo_path_matches_pattern(const struct tomoyo_path_info *filename, */ const char *tomoyo_get_exe(void) { + struct file *exe_file; + const char *cp; struct mm_struct *mm = current->mm; - const char *cp = NULL; if (!mm) return NULL; - down_read(&mm->mmap_sem); - if (mm->exe_file) - cp = tomoyo_realpath_from_path(&mm->exe_file->f_path); - up_read(&mm->mmap_sem); + exe_file = get_mm_exe_file(mm); + if (!exe_file) + return NULL; + + cp = tomoyo_realpath_from_path(&exe_file->f_path); + fput(exe_file); return cp; } -- cgit v1.2.3