From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>,
linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org,
Matt Mackall <mpm@selenic.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
Peter Huewe <peterhuewe@gmx.de>,
Marcel Selhorst <tpmdd@selhorst.net>,
Mimi Zohar <zohar@linux.vnet.ibm.com>,
Dmitry Kasatkin <dmitry.kasatkin@gmail.com>,
James Morris <james.l.morris@oracle.com>,
"Serge E. Hallyn" <serge@hallyn.com>,
David Safford <safford@us.ibm.com>,
David Howells <dhowells@redhat.com>,
Jerry Snitselaar <jsnitsel@redhat.com>,
"open list:HARDWARE RANDOM NUMBER GENERATOR CORE"
<linux-crypto@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>,
"moderated list:TPM DEVICE DRIVER"
<tpmdd-devel@lists.sourceforge.net>
Subject: Re: [PATCH v2] tpm: use struct tpm_chip for tpm_chip_find_get()
Date: Wed, 25 Oct 2017 13:46:33 -0600 [thread overview]
Message-ID: <20171025194633.GB998@obsidianresearch.com> (raw)
In-Reply-To: <20171025193452.d4qa4dhacfgqejk7@linux.intel.com>
> 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
next prev parent reply other threads:[~2017-10-25 19:46 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-25 11:55 [PATCH v2] tpm: use struct tpm_chip for tpm_chip_find_get() Jarkko Sakkinen
2017-10-25 15:10 ` PrasannaKumar Muralidharan
2017-10-25 19:34 ` Jarkko Sakkinen
2017-10-25 19:46 ` Jason Gunthorpe [this message]
2017-10-25 20:07 ` Jarkko Sakkinen
[not found] ` <20171025200746.svsraubdotjyzt2i-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2017-10-25 20:17 ` Jason Gunthorpe
2017-10-26 10:54 ` Jarkko Sakkinen
2017-10-25 15:22 ` Jason Gunthorpe
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