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>

diff --git a/kernel/acct.c b/kernel/acct.c
index f9ef9db55c0e4dc4c98c66fdb71ee07614c4edba..019f012a3c6fd1f9e4a6d3d564a44b1ca1d4baf7 100644 (file)
--- 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);