From mboxrd@z Thu Jan 1 00:00:00 1970 From: jarkko.sakkinen@linux.intel.com (Jarkko Sakkinen) Date: Tue, 28 Nov 2017 22:19:03 +0200 Subject: [PATCH v4 2/4] tpm: ignore burstcount to improve tpm_tis send() performance In-Reply-To: <694703AB-68E1-4026-937C-61DBBE08DB4B@paramecium.org> References: <20171017203232.2262-1-nayna@linux.vnet.ibm.com> <20171017203232.2262-3-nayna@linux.vnet.ibm.com> <5ef60315f2254b3b8bcc217a572280e5@infineon.com> <3ff12c6536de4379aa61cb09ebc9d105@infineon.com> <20171123144742.GC8862@swastik> <20171126152218.c5fsr7uhs3ipwwha@linux.intel.com> <1511714261.4361.13.camel@linux.vnet.ibm.com> <694703AB-68E1-4026-937C-61DBBE08DB4B@paramecium.org> Message-ID: <20171128201903.ndd4j3xw3ubfaa4y@linux.intel.com> To: linux-security-module@vger.kernel.org List-Id: linux-security-module.vger.kernel.org On Mon, Nov 27, 2017 at 07:08:51AM +0000, Leendert van Doorn wrote: > Hmm, this is almost 20 years old code ( > > I think the original code did a burst write and didn't check for error > conditions until the very last byte write. I seem to remember that > there was some text in the original standard to that effect (this may > have gone back as far as IBM's ESS spec). > > The current code does check for error conditions after each write > byte(s) so I don't think there is any reason for this anymore. > Changing the while condition to count < len and setting burstcnt = > min_t(int, burstcnt, len - count) and remove the > tpm_tis_write8/wait_for_tpm_stat/tpm_tis_status clauses after the > while loop should be sufficient. Thank you for sharing this! > Leendert /Jarkko -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html