linux-kernel - Re: [PATCH v3 3/3] KEYS: Use kvmalloc() to better handle large buffer allocation

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Message-ID: <20200315215253.GG224162@linux.intel.com>
Date:   Sun, 15 Mar 2020 23:52:53 +0200
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Waiman Long <longman@...hat.com>
Cc:     Eric Biggers <ebiggers@...nel.org>,
        David Howells <dhowells@...hat.com>,
        James Morris <jmorris@...ei.org>,
        "Serge E. Hallyn" <serge@...lyn.com>,
        Mimi Zohar <zohar@...ux.ibm.com>, keyrings@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        linux-security-module@...r.kernel.org,
        linux-integrity@...r.kernel.org,
        Sumit Garg <sumit.garg@...aro.org>,
        Jerry Snitselaar <jsnitsel@...hat.com>,
        Roberto Sassu <roberto.sassu@...wei.com>,
        Chris von Recklinghausen <crecklin@...hat.com>
Subject: Re: [PATCH v3 3/3] KEYS: Use kvmalloc() to better handle large
 buffer allocation

On Fri, Mar 13, 2020 at 01:49:57PM -0400, Waiman Long wrote:
> >>  			if (!tmpbuf || unlikely(ret > tmpbuflen)) {
> >>  				if (unlikely(tmpbuf))
> >> -					kzfree(tmpbuf);
> >> +					__kvzfree(tmpbuf, tmpbuflen);
> > Both kzfree() and __kvzfree() handle a NULL pointer, so there's no need for the
> > NULL check first.
> >
> I would like to keep this one because of the unlikely annotation.

What (measurable) gain does it bring anyway?

/Jarkko