From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AF106244664 for ; Thu, 13 Nov 2025 09:07:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.158.5 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763024830; cv=none; b=MucvQCAfSLU/wxwJAP7fN0m7vFQA3h9ny33KIL8p4NdmNxVJvAcjFEAn87g5xDEr/gfTdpnNWJpMFcjao/UrsqWg+ntdCxMQJcvNpR4NW9ZTSb9szPJWFTr8x+78O3Hd8l3XhF6lIv3ZN/sOBGbwhNy/oOeACdKfC/Pz0+pJYHw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763024830; c=relaxed/simple; bh=moX0jhIuq/NvbwpSnpWsqhr6enWecrpPytvBQ94pM2w=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JTLYvNvCSA258OizZoJM3SP/kLFR1R20WUUGE3Xs4Cstkf62MNKAU9PKUTd+EDy6Rs8e46LAWjhLyavuTIuJ6QShfk6ECeMfGzR2wFECRnJqkyWKO7a/DEtmJLJHDsAlJrAtg4XYXbQFw9zhZIxDeREAy0eRfY7u2ADfcjSA2RM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=bcd9eex4; arc=none smtp.client-ip=148.163.158.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="bcd9eex4" Received: from pps.filterd (m0353725.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 5ACIIHN6011435; Thu, 13 Nov 2025 09:06:38 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:date:from:in-reply-to:message-id :mime-version:references:subject:to; s=pp1; bh=YI9acWQlJchprr1VG bNp0yker1CM+xUKquVPAUl36Xw=; b=bcd9eex4BczYhQ0yibp8LgU4gr9P3yTLP zDr+CRu/JYgf4mCtWzVW2sjOxtv023G5U8iz7ddvGfm3zoQ497ELLCzV0l5/eoRd hdUVW7yRfzgjs9f3dWT91Qxlb6K7REiTrL8uXVUCbKSmgIurb5YX9zz9fvAqg+L1 fQVgf3Lh/GRXkSzxtoS1NpLhPuFhKki0A6M/sbBdz3N2MQWWtgw4ITsbgVxNHjS8 zpOksDZ4+kks1z4cNvwM8ig5H7Y8f1RqPY9Y4EVBxll34LuVnAQbaLGRRr7hJ2+i pqVcS53tCpccN9hA0oc6bo7ZnIw/Xk9/a1GbBOTNkNqSFZCpPzVUw== Received: from ppma21.wdc07v.mail.ibm.com (5b.69.3da9.ip4.static.sl-reverse.com [169.61.105.91]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4aa5tk4djf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 13 Nov 2025 09:06:37 +0000 (GMT) Received: from pps.filterd (ppma21.wdc07v.mail.ibm.com [127.0.0.1]) by ppma21.wdc07v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 5AD50NGq008193; Thu, 13 Nov 2025 09:06:37 GMT Received: from smtprelay02.fra02v.mail.ibm.com ([9.218.2.226]) by ppma21.wdc07v.mail.ibm.com (PPS) with ESMTPS id 4aah6n4xk3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 13 Nov 2025 09:06:37 +0000 Received: from smtpav02.fra02v.mail.ibm.com (smtpav02.fra02v.mail.ibm.com [10.20.54.101]) by smtprelay02.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 5AD96ZfV49742146 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 13 Nov 2025 09:06:35 GMT Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 457382004B; Thu, 13 Nov 2025 09:06:35 +0000 (GMT) Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5C55A20043; Thu, 13 Nov 2025 09:06:33 +0000 (GMT) Received: from li-c9696b4c-3419-11b2-a85c-f9edc3bf8a84.in.ibm.com (unknown [9.109.198.209]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTP; Thu, 13 Nov 2025 09:06:33 +0000 (GMT) From: Nilay Shroff To: linux-block@vger.kernel.org Cc: ming.lei@redhat.com, hch@lst.de, axboe@kernel.dk, yi.zhang@redhat.com, czhong@redhat.com, yukuai@fnnas.com, gjoyce@ibm.com Subject: [PATCHv7 5/5] block: define alloc_sched_data and free_sched_data methods for kyber Date: Thu, 13 Nov 2025 14:28:22 +0530 Message-ID: <20251113090619.2030737-6-nilay@linux.ibm.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251113090619.2030737-1-nilay@linux.ibm.com> References: <20251113090619.2030737-1-nilay@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: WdIAEgd6MP_nWV_hFysbUZ1Ibjpobj8T X-Proofpoint-ORIG-GUID: WdIAEgd6MP_nWV_hFysbUZ1Ibjpobj8T X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTA4MDA5OSBTYWx0ZWRfX3KvvLcKPTfA1 stBFHBpENjrl3mL1IbLWvRSgJ2fHmVFHhoMMBZqDpioDu7hXh4W7A9FfxYwW37/ODlWg/cn5MTc X+mi1BzIb/XkjRdjd6CKXdDOEHDRhEuZkoELO5ceuoiF7eymWINGdlY3fw1irIqcIlhWbQZAA6j q1sRp15nq9Dn2oPiURyw8+gXFV6dJvF43sI9FIP8IqlaaYAirKAwkyGvRLzLsWjBaYUyXhNa8jE oR3dy43KkB+ykqwyUoV0KM5nBjUYnMjOsjFHYMw148mWCVzzY9PnaS2r+UCHw4Cv8jqsqAAxYtb ry7MmsA2w0KgADkN9VwVyuUCHWGs6177MGdJkNj6szpLzvkrjQ88JKA0gxxeRGBaX9xEs59YOox rB6QoxesewBVeSNolcaQsFP+X+nvTg== X-Authority-Analysis: v=2.4 cv=V6xwEOni c=1 sm=1 tr=0 ts=69159f9e cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=6UeiqGixMTsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VwQbUJbxAAAA:8 a=pGLkceISAAAA:8 a=20KFwNOVAAAA:8 a=tJLSzyRPAAAA:8 a=VnNF1IyMAAAA:8 a=1sDiDhgU5wRd15m8xSAA:9 a=H0xsmVfZzgdqH4_HIfU3:22 a=cPQSjfK2_nFv0Q5t_7PE:22 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-11-13_01,2025-11-12_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 lowpriorityscore=0 adultscore=0 malwarescore=0 impostorscore=0 suspectscore=0 priorityscore=1501 phishscore=0 bulkscore=0 spamscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510240000 definitions=main-2511080099 Currently, the Kyber elevator allocates its private data dynamically in ->init_sched and frees it in ->exit_sched. However, since ->init_sched is invoked during elevator switch after acquiring both ->freeze_lock and ->elevator_lock, it may trigger the lockdep splat [1] due to dependency on pcpu_alloc_mutex. To resolve this, move the elevator data allocation and deallocation logic from ->init_sched and ->exit_sched into the newly introduced ->alloc_sched_data and ->free_sched_data methods. These callbacks are invoked before acquiring ->freeze_lock and ->elevator_lock, ensuring that memory allocation happens safely without introducing additional locking dependencies. This change breaks the dependency chain involving pcpu_alloc_mutex and prevents the reported lockdep warning. [1] https://lore.kernel.org/all/CAGVVp+VNW4M-5DZMNoADp6o2VKFhi7KxWpTDkcnVyjO0=-D5+A@mail.gmail.com/ Reported-by: Changhui Zhong Reported-by: Yi Zhang Closes: https://lore.kernel.org/all/CAGVVp+VNW4M-5DZMNoADp6o2VKFhi7KxWpTDkcnVyjO0=-D5+A@mail.gmail.com/ Tested-by: Yi Zhang Reviewed-by: Ming Lei Reviewed-by: Yu Kuai Signed-off-by: Nilay Shroff --- block/kyber-iosched.c | 30 ++++++++++++++++++++++-------- 1 file changed, 22 insertions(+), 8 deletions(-) diff --git a/block/kyber-iosched.c b/block/kyber-iosched.c index 18efd6ef2a2b..c1b36ffd19ce 100644 --- a/block/kyber-iosched.c +++ b/block/kyber-iosched.c @@ -409,30 +409,42 @@ static void kyber_depth_updated(struct request_queue *q) static int kyber_init_sched(struct request_queue *q, struct elevator_queue *eq) { - struct kyber_queue_data *kqd; - - kqd = kyber_queue_data_alloc(q); - if (IS_ERR(kqd)) - return PTR_ERR(kqd); - blk_stat_enable_accounting(q); blk_queue_flag_clear(QUEUE_FLAG_SQ_SCHED, q); - eq->elevator_data = kqd; q->elevator = eq; kyber_depth_updated(q); return 0; } +static void *kyber_alloc_sched_data(struct request_queue *q) +{ + struct kyber_queue_data *kqd; + + kqd = kyber_queue_data_alloc(q); + if (IS_ERR(kqd)) + return NULL; + + return kqd; +} + static void kyber_exit_sched(struct elevator_queue *e) { struct kyber_queue_data *kqd = e->elevator_data; - int i; timer_shutdown_sync(&kqd->timer); blk_stat_disable_accounting(kqd->q); +} + +static void kyber_free_sched_data(void *elv_data) +{ + struct kyber_queue_data *kqd = elv_data; + int i; + + if (!kqd) + return; for (i = 0; i < KYBER_NUM_DOMAINS; i++) sbitmap_queue_free(&kqd->domain_tokens[i]); @@ -1004,6 +1016,8 @@ static struct elevator_type kyber_sched = { .exit_sched = kyber_exit_sched, .init_hctx = kyber_init_hctx, .exit_hctx = kyber_exit_hctx, + .alloc_sched_data = kyber_alloc_sched_data, + .free_sched_data = kyber_free_sched_data, .limit_depth = kyber_limit_depth, .bio_merge = kyber_bio_merge, .prepare_request = kyber_prepare_request, -- 2.51.0