linux-kernel - [PATCH] fs/file.c: tidy up close

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1444327687-2923-1-git-send-email-mguzik@redhat.com>
Date:	Thu,  8 Oct 2015 20:08:07 +0200
From:	Mateusz Guzik <mguzik@...hat.com>
To:	Alexander Viro <viro@...iv.linux.org.uk>
Cc:	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
	Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH] fs/file.c: tidy up close_files

Improve consistency by reorganizing the code to use the same constructs
as do_close_on_exec.

Get rid of xchg of the file pointer. Since the table is about to be
freed there is no reason to NULLify the slot.

Get rid of the file NULL check. At this stage a bit set is supposed to
guarantee the slot is populated.

Signed-off-by: Mateusz Guzik <mguzik@...hat.com>
---
 fs/file.c | 27 +++++++++++----------------
 1 file changed, 11 insertions(+), 16 deletions(-)

diff --git a/fs/file.c b/fs/file.c
index 6c672ad..103d931 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -365,7 +365,7 @@ out:
 	return NULL;
 }
 
-static struct fdtable *close_files(struct files_struct * files)
+static struct fdtable *close_files(struct files_struct *files)
 {
 	/*
 	 * It is safe to dereference the fd table without RCU or
@@ -373,24 +373,19 @@ static struct fdtable *close_files(struct files_struct * files)
 	 * files structure.
 	 */
 	struct fdtable *fdt = rcu_dereference_raw(files->fdt);
-	int i, j = 0;
+	unsigned i;
 
-	for (;;) {
+	for (i = 0; ; i++) {
 		unsigned long set;
-		i = j * BITS_PER_LONG;
-		if (i >= fdt->max_fds)
+		unsigned fd = i * BITS_PER_LONG;
+		if (fd >= fdt->max_fds)
 			break;
-		set = fdt->open_fds[j++];
-		while (set) {
-			if (set & 1) {
-				struct file * file = xchg(&fdt->fd[i], NULL);
-				if (file) {
-					filp_close(file, files);
-					cond_resched_rcu_qs();
-				}
-			}
-			i++;
-			set >>= 1;
+		set = fdt->open_fds[i];
+		for ( ; set ; fd++, set >>= 1) {
+			if (!(set & 1))
+				continue;
+			filp_close(fdt->fd[fd], files);
+			cond_resched_rcu_qs();
 		}
 	}
 
-- 
1.8.3.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/