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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>
This commit is contained in:
Al Viro 2014-04-19 14:24:18 -04:00
parent b8f00e6be4
commit 54a4d58a64
1 changed files with 11 additions and 39 deletions
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50
kernel/acct.c
View File

@ -93,64 +93,36 @@ static LIST_HEAD(acct_list);
/* /*
* Check the amount of free space and suspend/resume accordingly. * 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; struct kstatfs sbuf;
int res;
int act;
u64 resume;
u64 suspend;
spin_lock(&acct_lock); if (time_is_before_jiffies(acct->needcheck))
res = acct->active;
if (!file || time_is_before_jiffies(acct->needcheck))
goto out; goto out;
spin_unlock(&acct_lock);
/* May block */ /* May block */
if (vfs_statfs(&file->f_path, &sbuf)) if (vfs_statfs(&acct->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;
goto out; goto out;
}
if (acct->active) { if (acct->active) {
if (act < 0) { u64 suspend = sbuf.f_blocks * SUSPEND;
do_div(suspend, 100);
if (sbuf.f_bavail <= suspend) {
acct->active = 0; acct->active = 0;
printk(KERN_INFO "Process accounting paused\n"); printk(KERN_INFO "Process accounting paused\n");
} }
} else { } else {
if (act > 0) { u64 resume = sbuf.f_blocks * RESUME;
do_div(resume, 100);
if (sbuf.f_bavail >= resume) {
acct->active = 1; acct->active = 1;
printk(KERN_INFO "Process accounting resumed\n"); printk(KERN_INFO "Process accounting resumed\n");
} }
} }
acct->needcheck = jiffies + ACCT_TIMEOUT*HZ; acct->needcheck = jiffies + ACCT_TIMEOUT*HZ;
res = acct->active;
out: out:
spin_unlock(&acct_lock); return acct->active;
return res;
} }
static void acct_put(struct bsd_acct_struct *p) 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 * First check to see if there is enough free_space to continue
* the process accounting system. * the process accounting system.
*/ */
if (!check_free_space(acct, file)) if (!check_free_space(acct))
goto out; goto out;
fill_ac(&ac); fill_ac(&ac);