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Petersen" , Ard Biesheuvel , Jeffrey Lien , Christoph Hellwig , "linux-kernel\@vger.kernel.org" , "linux-crypto\@vger.kernel.org" , "linux-block\@vger.kernel.org" , "linux-scsi\@vger.kernel.org" , "tim.c.chen\@linux.intel.com" , David Darrington , Jeff Furlong Subject: Re: [PATCH] Performance Improvement in CRC16 Calculations. From: "Martin K. Petersen" Organization: Oracle Corporation References: <1533928331-21303-1-git-send-email-jeff.lien@wdc.com> <20180822062016.GA10356@infradead.org> <20180825061205.ygrjjazkooqghrqy@gondor.apana.org.au> Date: Sat, 25 Aug 2018 22:35:23 -0400 In-Reply-To: <20180825061205.ygrjjazkooqghrqy@gondor.apana.org.au> (Herbert Xu's message of "Sat, 25 Aug 2018 14:12:05 +0800") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8996 signatures=668707 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=633 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1808260026 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Herbert, > I don't think this is safe unless you do some kind of locking > which would slow down the data path. The easiest fix would be > to keep the old tfm around forever, or use RCU if RCU read locking > is acceptable to your use-case. You're right. There's a small race there. Patch series coming... -- Martin K. Petersen Oracle Linux Engineering