acct: simplify check_free_space()

a) file can't be NULL
b) file can't be changed under us
c) all writes are serialized by acct->lock; no need to mess with
spinlock there.

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

1 files changed, 11 insertions, 39 deletions

diff --git a/kernel/acct.c b/kernel/acct.c
index f9ef9db55c0e..019f012a3c6f 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -93,64 +93,36 @@ static LIST_HEAD(acct_list);
 /*
  * Check the amount of free space and suspend/resume accordingly.
  */
-static int check_free_space(struct bsd_acct_struct *acct, struct file *file)
+static int check_free_space(struct bsd_acct_struct *acct)
 {
         struct kstatfs sbuf;
-        int res;
-        int act;
-        u64 resume;
-        u64 suspend;
 
-        spin_lock(&acct_lock);
-        res = acct->active;
-        if (!file || time_is_before_jiffies(acct->needcheck))
+        if (time_is_before_jiffies(acct->needcheck))
                 goto out;
-        spin_unlock(&acct_lock);
 
         /* May block */
-        if (vfs_statfs(&file->f_path, &sbuf))
-                return res;
-        suspend = sbuf.f_blocks * SUSPEND;
-        resume = sbuf.f_blocks * RESUME;
-
-        do_div(suspend, 100);
-        do_div(resume, 100);
-
-        if (sbuf.f_bavail <= suspend)
-                act = -1;
-        else if (sbuf.f_bavail >= resume)
-                act = 1;
-        else
-                act = 0;
-
-        /*
-         * If some joker switched acct->file under us we'ld better be
-         * silent and _not_ touch anything.
-         */
-        spin_lock(&acct_lock);
-        if (file != acct->file) {
-                if (act)
-                        res = act > 0;
+        if (vfs_statfs(&acct->file->f_path, &sbuf))
                 goto out;
-        }
 
         if (acct->active) {
-                if (act < 0) {
+                u64 suspend = sbuf.f_blocks * SUSPEND;
+                do_div(suspend, 100);
+                if (sbuf.f_bavail <= suspend) {
                         acct->active = 0;
                         printk(KERN_INFO "Process accounting paused\n");
                 }
         } else {
-                if (act > 0) {
+                u64 resume = sbuf.f_blocks * RESUME;
+                do_div(resume, 100);
+                if (sbuf.f_bavail >= resume) {
                         acct->active = 1;
                         printk(KERN_INFO "Process accounting resumed\n");
                 }
         }
 
         acct->needcheck = jiffies + ACCT_TIMEOUT*HZ;
-        res = acct->active;
 out:
-        spin_unlock(&acct_lock);
-        return res;
+        return acct->active;
 }
 
 static void acct_put(struct bsd_acct_struct *p)
@@ -550,7 +522,7 @@ static void do_acct_process(struct bsd_acct_struct *acct)
          * First check to see if there is enough free_space to continue
          * the process accounting system.
          */
-        if (!check_free_space(acct, file))
+        if (!check_free_space(acct))
                 goto out;
 
         fill_ac(&ac);