> struct tpm_chip *tpm_chip_find_get(u64 id)
> {
> struct tpm_chup *chip;
> struct tpm_chip *res = NULL;
> int chip_num = 0;
> int chip_prev;
>
> mutex_lock(&idr_lock);
>
> do {
> chip_prev = chip_num;
>
> chip = idr_get_next(&dev_nums_idr, &chip_num);
>
> if (chip && (!id || id == chip->id) && !tpm_try_get_ops(chip)) {
> res = chip;
> break;
> }
> } while (chip_prev != chip_num);
>
> mutex_unlock(&idr_lock);
>
> return res;
> }
?? The old version was correct, idr_find_slowpath is better than an
idr_get_next serach if you already know id.
PrasannaKumar's solution seems right, if we already have chip, then we
just need to lock it again:
struct tpm_chip *tpm_chip_find_get(struct tpm_chip *chip)
{
struct tpm_chip *res = NULL;
mutex_lock(&idr_lock);
if (!chip) {
int chip_num = 0;
int chip_prev;
do {
chip_prev = chip_num;
chip = idr_get_next(&dev_nums_idr, &chip_num);
if (chip && !tpm_try_get_ops(chip)) {
res = chip;
break;
}
} while (chip_prev != chip_num);
} else {
if (!tpm_try_get_ops(chip))
res = chip;
}
mutex_unlock(&idr_lock);
return res;
}
Jason
From 1582259499724838388@xxx Wed Oct 25 19:37:26 +0000 2017
X-GM-THRID: 1582230549885813514
X-Gmail-Labels: Inbox,Category Forums