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Tue, 28 Jul 2026 16:13:33 +0000 (GMT) Received: from ltc.linux.ibm.com (unknown [9.5.196.140]) by smtpav06.dal12v.mail.ibm.com (Postfix) with ESMTP; Tue, 28 Jul 2026 16:13:32 +0000 (GMT) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Date: Tue, 28 Jul 2026 18:13:32 +0200 From: Harald Freudenberger To: Heiko Carstens Cc: Alexander Gordeev , Sven Schnelle , Vasily Gorbik , Christian Borntraeger , Holger Dengler , Vineeth Vijayan , Peter Oberparleiter , Janosch Frank , Claudio Imbrenda , David Hildenbrand , Peter Zijlstra , Herbert Xu , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org Subject: Re: [PATCH v2 1/4] s390/crypto: Replace cond_resched() with msleep(1) Reply-To: freude@linux.ibm.com Mail-Reply-To: freude@linux.ibm.com In-Reply-To: <20260728150412.3893933-2-hca@linux.ibm.com> References: <20260728150412.3893933-1-hca@linux.ibm.com> <20260728150412.3893933-2-hca@linux.ibm.com> Message-ID: <2cbaf523a137849d351d7393058286e2@linux.ibm.com> X-Sender: freude@linux.ibm.com Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: VgBQ2d4R80tmrpmdv7Knm86Yqi-VpGuy X-Proofpoint-ORIG-GUID: VgBQ2d4R80tmrpmdv7Knm86Yqi-VpGuy X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzI4MDE0MCBTYWx0ZWRfX5u+H2DCBGGnH WL1vke0YM/FQTQhjj9f5fbZLsm8BjnZLcn6KM/vKNAfl45+VYNfOYRvOs3p8FUw8fIxRmMo92dg R5BTpOiJbNoUt+OE3fFrgqBdPhEZiNfKTjvTlgl7T77iUkyN/+7CGCLIsjaMqCx0QiJPzM2whlN +lEao7KMmJOvi7iuP59W1y6Z5xZdhmWnC5jHrjIJgIz/cU/zEMuzbVECoyGj4KucFUKP6j4+tXh 3m/8HO9QZSOoiUXk9vjv5xZNoahjHcTAP+F1f+fm7D4n1qaQLaqKyUXXXgW8Y8kIaKYTMr92fFx G0kJooFcaOF2VKEuhj7cpWugjB9fTnqm2FyPq084PNMU3JGjbGFOHVXTedVaKDQln0rLlL1zUYW ixDhQ/42hQSVNnOkJ/q1bVuxg9VLiNwz1h1nJfdUHrrNIDTeH9lM3B4pWjuCNyb9CSRdGhPZnxi FllvEeWOYY419frXQxA== X-Authority-Analysis: v=2.4 cv=SKFykuvH c=1 sm=1 tr=0 ts=6a68d530 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=kj9zAlcOel0A:10 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=VnNF1IyMAAAA:8 a=DcPO_hv44LQIqzGHYZIA:9 a=CjuIK1q_8ugA:10 X-Proofpoint-Spam-Info: AW1haW4tMjYwNzI4MDE0MCBTYWx0ZWRfX6Zuw39tXzSFa waHq+FWcQXft8JyDTp0q2MPE3VwpCDUQbZFIRtBuLGgOiii6EoHF2ch1J71t3DJ46ZoDGYqzYze LiI3hS7Lp/eis2lo3lI51ko9TNqHNw4= X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-28_04,2026-07-28_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 clxscore=1015 adultscore=0 lowpriorityscore=0 bulkscore=0 impostorscore=0 phishscore=0 spamscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607280140 On 2026-07-28 17:04, Heiko Carstens wrote: > With [1] cond_resched() is always compiled away and becomes a no-op. > > The comments for all cond_resched() calls in crypto code however > indicate > that the current process should be scheduled away to avoid instant > re-invocation of a callback. This is not what cond_resched() would do > or > did. > > Instead of just removing the cond_resched() calls, replace them with > msleep() calls, as suggested by Holger Dengler. This forces the current > task to be scheduled away (sleeps) like originally intended. > > [1] commit 7dadeaa6e851 ("sched: Further restrict the preemption > modes") > > Signed-off-by: Heiko Carstens > --- > arch/s390/crypto/paes_s390.c | 8 ++++---- > arch/s390/crypto/phmac_s390.c | 4 ++-- > 2 files changed, 6 insertions(+), 6 deletions(-) > > diff --git a/arch/s390/crypto/paes_s390.c > b/arch/s390/crypto/paes_s390.c > index 8cfe6166c193..511cb6105436 100644 > --- a/arch/s390/crypto/paes_s390.c > +++ b/arch/s390/crypto/paes_s390.c > @@ -555,7 +555,7 @@ static int ecb_paes_do_one_request(struct > crypto_engine *engine, void *areq) > * To avoid immediately re-invocation of this callback, > * tell the scheduler to voluntarily give up the CPU here. > */ > - cond_resched(); > + msleep(1); > pr_debug("rescheduling request\n"); > return -ENOSPC; > } else if (rc) { > @@ -821,7 +821,7 @@ static int cbc_paes_do_one_request(struct > crypto_engine *engine, void *areq) > * To avoid immediately re-invocation of this callback, > * tell the scheduler to voluntarily give up the CPU here. > */ > - cond_resched(); > + msleep(1); > pr_debug("rescheduling request\n"); > return -ENOSPC; > } else if (rc) { > @@ -1129,7 +1129,7 @@ static int ctr_paes_do_one_request(struct > crypto_engine *engine, void *areq) > * To avoid immediately re-invocation of this callback, > * tell the scheduler to voluntarily give up the CPU here. > */ > - cond_resched(); > + msleep(1); > pr_debug("rescheduling request\n"); > return -ENOSPC; > } else if (rc) { > @@ -1572,7 +1572,7 @@ static int xts_paes_do_one_request(struct > crypto_engine *engine, void *areq) > * To avoid immediately re-invocation of this callback, > * tell the scheduler to voluntarily give up the CPU here. > */ > - cond_resched(); > + msleep(1); > pr_debug("rescheduling request\n"); > return -ENOSPC; > } else if (rc) { > diff --git a/arch/s390/crypto/phmac_s390.c > b/arch/s390/crypto/phmac_s390.c > index 03ca33ffe6cc..da76c7beb184 100644 > --- a/arch/s390/crypto/phmac_s390.c > +++ b/arch/s390/crypto/phmac_s390.c > @@ -895,7 +895,7 @@ static int phmac_do_one_request(struct > crypto_engine *engine, void *areq) > * tell scheduler to voluntarily give up the CPU here. > */ > pr_debug("rescheduling request\n"); > - cond_resched(); > + msleep(1); > return -ENOSPC; > } else if (rc) { > hwh_advance(hwh, rc); > @@ -916,7 +916,7 @@ static int phmac_do_one_request(struct > crypto_engine *engine, void *areq) > * tell scheduler to voluntarily give up the CPU here. > */ > pr_debug("rescheduling request\n"); > - cond_resched(); > + msleep(1); > return -ENOSPC; > } > break; Reviewed-by: Harald Freudenberger