commit ed44724b79d8e03a40665436019cf22baba80d30
author Al Viro <viro@zeniv.linux.org.uk> Sat Apr 19 14:37:20 2014 -0400
committer Al Viro <viro@zeniv.linux.org.uk> Thu Aug 07 14:40:07 2014 -0400
tree 9062239f57fbffff21bbd81cf28b6dc45081722b
parent ecfdb33d1fbc7e6e095ba24dac2930208494e734

acct: switch to __kernel_write()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

kernel/acct.c

diff --git a/kernel/acct.c b/kernel/acct.c
index 807ebc5..8082d98 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -456,12 +456,16 @@
 {
 	struct pacct_struct *pacct = &current->signal->pacct;
 	acct_t ac;
-	mm_segment_t fs;
 	unsigned long flim;
 	u64 elapsed, run_time;
 	struct tty_struct *tty;
 	const struct cred *orig_cred;
 
+	/*
+	 * Accounting records are not subject to resource limits.
+	 */
+	flim = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
+	current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
 	/* Perform file operations on behalf of whoever enabled accounting */
 	orig_cred = override_creds(file->f_cred);
 
@@ -536,25 +540,14 @@
 	 * Get freeze protection. If the fs is frozen, just skip the write
 	 * as we could deadlock the system otherwise.
 	 */
-	if (!file_start_write_trylock(file))
-		goto out;
-	/*
-	 * Kernel segment override to datasegment and write it
-	 * to the accounting file.
-	 */
-	fs = get_fs();
-	set_fs(KERNEL_DS);
-	/*
-	 * Accounting records are not subject to resource limits.
-	 */
-	flim = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
-	current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
-	file->f_op->write(file, (char *)&ac,
-			       sizeof(acct_t), &file->f_pos);
-	current->signal->rlim[RLIMIT_FSIZE].rlim_cur = flim;
-	set_fs(fs);
-	file_end_write(file);
+	if (file_start_write_trylock(file)) {
+		/* it's been opened O_APPEND, so position is irrelevant */
+		loff_t pos = 0;
+		__kernel_write(file, (char *)&ac, sizeof(acct_t), &pos);
+		file_end_write(file);
+	}
 out:
+	current->signal->rlim[RLIMIT_FSIZE].rlim_cur = flim;
 	revert_creds(orig_cred);
 }