Re: [PATCH][FAT] FAT dirent scan with hin take #3

Pekka Enberg
2005-08-31T13:51:14Z

On 8/31/05, Machida, Hiroyuki <machida@sm.sony.co.jp> wrote:
> How about this ?
>
> if (!MSDOS_I(dir)->scan_hints) {
> hints = kcalllo(....);
>
> down
> if (MSDOS_I(dir)->scan_hints) {
> up
> goto already_allocated;
> }
> if (hints)
> MSDOS_I(dir)->scan_hints = hints;
> up
> }
> return (hints == 0) ? -ENOMEM : 0;
>
> already_allocated:
> kfree(hints); /* kfree accepts NULL */
> return 0;

After finally understanding what you're doing, how about:

static inline int hint_allocate(struct inode *dir)
{
loff_t *hints;
int err = 0;

if (!MSDOS_I(dir)->scan_hints)
return 0;

hints = kcalloc(FAT_SCAN_NWAY, sizeof(loff_t), GFP_KERNEL);
if (!hints)
err = -ENOMEM;

down(&MSDOS_I(dir)->scan_lock);
/*
* We allocated memory without scan_lock so lets make sure
* no other thread completed hint_allocate() before us.
*/
if (!MSDOS_I(dir)->scan_hints) {
MSDOS_I(dir)->scan_hints = hints;
hints = NULL;
}
up(&MSDOS_I(dir)->scan_lock);

kfree(hints);
return err;
}

Pekka