From patchwork Fri Jul 7 10:43:57 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Niklas Schnelle X-Patchwork-Id: 13304719 X-Patchwork-Delegate: kuba@kernel.org Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 AF49720E0 for ; Fri, 7 Jul 2023 10:44:13 +0000 (UTC) Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5A8AA172B; Fri, 7 Jul 2023 03:44:11 -0700 (PDT) Received: from pps.filterd (m0353725.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 367Afqua023791; Fri, 7 Jul 2023 10:44:08 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pp1; bh=FiXmI2k/9244Z9oQXE/8cOVrPyhmB3N3R1TpxJXn6ew=; b=qVKbP9Pxvzsg652hqOib9ebKCJ4pyPPWi2N4Ra+sMvp67ymvlgYVg1DAEg3AHjosFagH OICXqgBmOF0XYr2WMJ7IcjCGI9hGicW+rJc/qNL2KbNdGuprVbIuhbmB612gy0PloRgq 7R6YFcH7ffgHb09ZPLat07BCHEbw/Y8ADCDiNQ0uxGirctI1xspn5b+n7aHWpWwVWKfY ZZlc8wLJ9hRbB6lJz+UOMPAlBVqVN9LRiT1bZtN7CKANXAWNtJ8jr5giKS+XIvg8rhgV 7mb+oWCnuWa+iHGYA8f4Q+1vp/k3aKfBRBnNyz9ycsdLPeOH3TE9dTGwAWyKa7phlUzu 0A== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3rpgu3rc9y-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 07 Jul 2023 10:44:08 +0000 Received: from m0353725.ppops.net (m0353725.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 367Afw2s023990; Fri, 7 Jul 2023 10:44:07 GMT Received: from ppma03ams.nl.ibm.com (62.31.33a9.ip4.static.sl-reverse.com [169.51.49.98]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3rpgu3rc9a-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 07 Jul 2023 10:44:07 +0000 Received: from pps.filterd (ppma03ams.nl.ibm.com [127.0.0.1]) by ppma03ams.nl.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 3673KxD1020329; Fri, 7 Jul 2023 10:44:05 GMT Received: from smtprelay04.fra02v.mail.ibm.com ([9.218.2.228]) by ppma03ams.nl.ibm.com (PPS) with ESMTPS id 3rjbs4uy42-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 07 Jul 2023 10:44:05 +0000 Received: from smtpav02.fra02v.mail.ibm.com (smtpav02.fra02v.mail.ibm.com [10.20.54.101]) by smtprelay04.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 367Ai0QJ43451048 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 7 Jul 2023 10:44:00 GMT Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id BB82120040; Fri, 7 Jul 2023 10:44:00 +0000 (GMT) Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3ED762005A; Fri, 7 Jul 2023 10:44:00 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTP; Fri, 7 Jul 2023 10:44:00 +0000 (GMT) From: Niklas Schnelle To: Paolo Abeni , Alexandra Winter , Wenjia Zhang , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , "David S. Miller" , Stefan Raspl , Jan Karcher Cc: linux-s390@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net v2 1/3] s390/ism: Fix locking for forwarding of IRQs and events to clients Date: Fri, 7 Jul 2023 12:43:57 +0200 Message-Id: <20230707104359.3324039-2-schnelle@linux.ibm.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230707104359.3324039-1-schnelle@linux.ibm.com> References: <20230707104359.3324039-1-schnelle@linux.ibm.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: ComVDJxSxacbzW_OLn79l4BaJ_GuzV1z X-Proofpoint-GUID: rW-lHT37QAAq0u_DLXGZTBgK5EUXHcWP X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.957,Hydra:6.0.591,FMLib:17.11.176.26 definitions=2023-07-07_06,2023-07-06_02,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 priorityscore=1501 malwarescore=0 clxscore=1015 phishscore=0 adultscore=0 spamscore=0 impostorscore=0 mlxlogscore=869 mlxscore=0 bulkscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2305260000 definitions=main-2307070097 X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org The clients array references all registered clients and is protected by the clients_lock. Besides its use as general list of clients the clients array is accessed in ism_handle_irq() to forward ISM device events to clients. While the clients_lock is taken in the IRQ handler when calling handle_event() it is however incorrectly not held during the client->handle_irq() call and for the preceding clients[] access leaving it unprotected against concurrent client (un-)registration. Furthermore the accesses to ism->sba_client_arr[] in ism_register_dmb() and ism_unregister_dmb() are not protected by any lock. This is especially problematic as the client ID from the ism->sba_client_arr[] is not checked against NO_CLIENT and neither is the client pointer checked. Instead of expanding the use of the clients_lock further add a separate array in struct ism_dev which references clients subscribed to the device's events and IRQs. This array is protected by ism->lock which is already taken in ism_handle_irq() and can be taken outside the IRQ handler when adding/removing subscribers or the accessing ism->sba_client_arr[]. This also means that the clients_lock is no longer taken in IRQ context. Fixes: 89e7d2ba61b7 ("net/ism: Add new API for client registration") Signed-off-by: Niklas Schnelle --- drivers/s390/net/ism_drv.c | 44 +++++++++++++++++++++++++++++++------- include/linux/ism.h | 1 + 2 files changed, 37 insertions(+), 8 deletions(-) diff --git a/drivers/s390/net/ism_drv.c b/drivers/s390/net/ism_drv.c index 9b5fccdbc7d6..b664e4a08645 100644 --- a/drivers/s390/net/ism_drv.c +++ b/drivers/s390/net/ism_drv.c @@ -47,6 +47,15 @@ static struct ism_dev_list ism_dev_list = { .mutex = __MUTEX_INITIALIZER(ism_dev_list.mutex), }; +static void ism_setup_forwarding(struct ism_client *client, struct ism_dev *ism) +{ + unsigned long flags; + + spin_lock_irqsave(&ism->lock, flags); + ism->subs[client->id] = client; + spin_unlock_irqrestore(&ism->lock, flags); +} + int ism_register_client(struct ism_client *client) { struct ism_dev *ism; @@ -71,6 +80,7 @@ int ism_register_client(struct ism_client *client) list_for_each_entry(ism, &ism_dev_list.list, list) { ism->priv[i] = NULL; client->add(ism); + ism_setup_forwarding(client, ism); } } mutex_unlock(&ism_dev_list.mutex); @@ -92,6 +102,9 @@ int ism_unregister_client(struct ism_client *client) max_client--; spin_unlock_irqrestore(&clients_lock, flags); list_for_each_entry(ism, &ism_dev_list.list, list) { + spin_lock_irqsave(&ism->lock, flags); + /* Stop forwarding IRQs and events */ + ism->subs[client->id] = NULL; for (int i = 0; i < ISM_NR_DMBS; ++i) { if (ism->sba_client_arr[i] == client->id) { pr_err("%s: attempt to unregister client '%s'" @@ -101,6 +114,7 @@ int ism_unregister_client(struct ism_client *client) goto out; } } + spin_unlock_irqrestore(&ism->lock, flags); } out: mutex_unlock(&ism_dev_list.mutex); @@ -328,6 +342,7 @@ int ism_register_dmb(struct ism_dev *ism, struct ism_dmb *dmb, struct ism_client *client) { union ism_reg_dmb cmd; + unsigned long flags; int ret; ret = ism_alloc_dmb(ism, dmb); @@ -351,7 +366,9 @@ int ism_register_dmb(struct ism_dev *ism, struct ism_dmb *dmb, goto out; } dmb->dmb_tok = cmd.response.dmb_tok; + spin_lock_irqsave(&ism->lock, flags); ism->sba_client_arr[dmb->sba_idx - ISM_DMB_BIT_OFFSET] = client->id; + spin_unlock_irqrestore(&ism->lock, flags); out: return ret; } @@ -360,6 +377,7 @@ EXPORT_SYMBOL_GPL(ism_register_dmb); int ism_unregister_dmb(struct ism_dev *ism, struct ism_dmb *dmb) { union ism_unreg_dmb cmd; + unsigned long flags; int ret; memset(&cmd, 0, sizeof(cmd)); @@ -368,7 +386,9 @@ int ism_unregister_dmb(struct ism_dev *ism, struct ism_dmb *dmb) cmd.request.dmb_tok = dmb->dmb_tok; + spin_lock_irqsave(&ism->lock, flags); ism->sba_client_arr[dmb->sba_idx - ISM_DMB_BIT_OFFSET] = NO_CLIENT; + spin_unlock_irqrestore(&ism->lock, flags); ret = ism_cmd(ism, &cmd); if (ret && ret != ISM_ERROR) @@ -491,6 +511,7 @@ static u16 ism_get_chid(struct ism_dev *ism) static void ism_handle_event(struct ism_dev *ism) { struct ism_event *entry; + struct ism_client *clt; int i; while ((ism->ieq_idx + 1) != READ_ONCE(ism->ieq->header.idx)) { @@ -499,21 +520,21 @@ static void ism_handle_event(struct ism_dev *ism) entry = &ism->ieq->entry[ism->ieq_idx]; debug_event(ism_debug_info, 2, entry, sizeof(*entry)); - spin_lock(&clients_lock); - for (i = 0; i < max_client; ++i) - if (clients[i]) - clients[i]->handle_event(ism, entry); - spin_unlock(&clients_lock); + for (i = 0; i < max_client; ++i) { + clt = ism->subs[i]; + if (clt) + clt->handle_event(ism, entry); + } } } static irqreturn_t ism_handle_irq(int irq, void *data) { struct ism_dev *ism = data; - struct ism_client *clt; unsigned long bit, end; unsigned long *bv; u16 dmbemask; + u8 client_id; bv = (void *) &ism->sba->dmb_bits[ISM_DMB_WORD_OFFSET]; end = sizeof(ism->sba->dmb_bits) * BITS_PER_BYTE - ISM_DMB_BIT_OFFSET; @@ -530,8 +551,10 @@ static irqreturn_t ism_handle_irq(int irq, void *data) dmbemask = ism->sba->dmbe_mask[bit + ISM_DMB_BIT_OFFSET]; ism->sba->dmbe_mask[bit + ISM_DMB_BIT_OFFSET] = 0; barrier(); - clt = clients[ism->sba_client_arr[bit]]; - clt->handle_irq(ism, bit + ISM_DMB_BIT_OFFSET, dmbemask); + client_id = ism->sba_client_arr[bit]; + if (unlikely(client_id == NO_CLIENT || !ism->subs[client_id])) + continue; + ism->subs[client_id]->handle_irq(ism, bit + ISM_DMB_BIT_OFFSET, dmbemask); } if (ism->sba->e) { @@ -554,6 +577,7 @@ static void ism_dev_add_work_func(struct work_struct *work) add_work); client->add(client->tgt_ism); + ism_setup_forwarding(client, client->tgt_ism); atomic_dec(&client->tgt_ism->add_dev_cnt); wake_up(&client->tgt_ism->waitq); } @@ -691,7 +715,11 @@ static void ism_dev_remove_work_func(struct work_struct *work) { struct ism_client *client = container_of(work, struct ism_client, remove_work); + unsigned long flags; + spin_lock_irqsave(&client->tgt_ism->lock, flags); + client->tgt_ism->subs[client->id] = NULL; + spin_unlock_irqrestore(&client->tgt_ism->lock, flags); client->remove(client->tgt_ism); atomic_dec(&client->tgt_ism->free_clients_cnt); wake_up(&client->tgt_ism->waitq); diff --git a/include/linux/ism.h b/include/linux/ism.h index ea2bcdae7401..5160d47e5ea9 100644 --- a/include/linux/ism.h +++ b/include/linux/ism.h @@ -44,6 +44,7 @@ struct ism_dev { u64 local_gid; int ieq_idx; + struct ism_client *subs[MAX_CLIENTS]; atomic_t free_clients_cnt; atomic_t add_dev_cnt; wait_queue_head_t waitq; From patchwork Fri Jul 7 10:43:58 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Niklas Schnelle X-Patchwork-Id: 13304721 X-Patchwork-Delegate: kuba@kernel.org Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 AED1AC12E for ; Fri, 7 Jul 2023 10:44:16 +0000 (UTC) Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EBB4010E2; Fri, 7 Jul 2023 03:44:14 -0700 (PDT) Received: from pps.filterd (m0353722.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 367Adhqi000645; Fri, 7 Jul 2023 10:44:13 GMT DKIM-Signature: v=1; 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Fri, 7 Jul 2023 10:44:01 +0000 (GMT) From: Niklas Schnelle To: Paolo Abeni , Alexandra Winter , Wenjia Zhang , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Jan Karcher , Stefan Raspl , "David S. Miller" Cc: linux-s390@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net v2 2/3] s390/ism: Fix and simplify add()/remove() callback handling Date: Fri, 7 Jul 2023 12:43:58 +0200 Message-Id: <20230707104359.3324039-3-schnelle@linux.ibm.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230707104359.3324039-1-schnelle@linux.ibm.com> References: <20230707104359.3324039-1-schnelle@linux.ibm.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: wsfRGkosQvCZvc7aRIZ466DEzzNXLSvK X-Proofpoint-ORIG-GUID: EyByd6bf-1JMg4NDGqyQNEs39WFTH0cP X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.957,Hydra:6.0.591,FMLib:17.11.176.26 definitions=2023-07-07_06,2023-07-06_02,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 priorityscore=1501 lowpriorityscore=0 suspectscore=0 mlxlogscore=999 phishscore=0 malwarescore=0 mlxscore=0 spamscore=0 bulkscore=0 impostorscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2305260000 definitions=main-2307070097 X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org Previously the clients_lock was protecting the clients array against concurrent addition/removal of clients but was also accessed from IRQ context. This meant that it had to be a spinlock and that the add() and remove() callbacks in which clients need to do allocation and take mutexes can't be called under the clients_lock. To work around this these callbacks were moved to workqueues. This not only introduced significant complexity but is also subtly broken in at least one way. In ism_dev_init() and ism_dev_exit() clients[i]->tgt_ism is used to communicate the added/removed ISM device to the work function. While write access to client[i]->tgt_ism is protected by the clients_lock and the code waits that there is no pending add/remove work before and after setting clients[i]->tgt_ism this is not enough. The problem is that the wait happens based on per ISM device counters. Thus a concurrent ism_dev_init()/ism_dev_exit() for a different ISM device may overwrite a clients[i]->tgt_ism between unlocking the clients_lock and the subsequent wait for the work to finnish. Thankfully with the clients_lock no longer held in IRQ context it can be turned into a mutex which can be held during the calls to add()/remove() completely removing the need for the workqueues and the associated broken housekeeping including the per ISM device counters and the clients[i]->tgt_ism. Fixes: 89e7d2ba61b7 ("net/ism: Add new API for client registration") Signed-off-by: Niklas Schnelle --- drivers/s390/net/ism_drv.c | 90 +++++++++++--------------------------- include/linux/ism.h | 6 --- 2 files changed, 26 insertions(+), 70 deletions(-) diff --git a/drivers/s390/net/ism_drv.c b/drivers/s390/net/ism_drv.c index b664e4a08645..54091b7aea16 100644 --- a/drivers/s390/net/ism_drv.c +++ b/drivers/s390/net/ism_drv.c @@ -36,7 +36,7 @@ static const struct smcd_ops ism_ops; static struct ism_client *clients[MAX_CLIENTS]; /* use an array rather than */ /* a list for fast mapping */ static u8 max_client; -static DEFINE_SPINLOCK(clients_lock); +static DEFINE_MUTEX(clients_lock); struct ism_dev_list { struct list_head list; struct mutex mutex; /* protects ism device list */ @@ -59,11 +59,10 @@ static void ism_setup_forwarding(struct ism_client *client, struct ism_dev *ism) int ism_register_client(struct ism_client *client) { struct ism_dev *ism; - unsigned long flags; int i, rc = -ENOSPC; mutex_lock(&ism_dev_list.mutex); - spin_lock_irqsave(&clients_lock, flags); + mutex_lock(&clients_lock); for (i = 0; i < MAX_CLIENTS; ++i) { if (!clients[i]) { clients[i] = client; @@ -74,7 +73,8 @@ int ism_register_client(struct ism_client *client) break; } } - spin_unlock_irqrestore(&clients_lock, flags); + mutex_unlock(&clients_lock); + if (i < MAX_CLIENTS) { /* initialize with all devices that we got so far */ list_for_each_entry(ism, &ism_dev_list.list, list) { @@ -96,11 +96,11 @@ int ism_unregister_client(struct ism_client *client) int rc = 0; mutex_lock(&ism_dev_list.mutex); - spin_lock_irqsave(&clients_lock, flags); + mutex_lock(&clients_lock); clients[client->id] = NULL; if (client->id + 1 == max_client) max_client--; - spin_unlock_irqrestore(&clients_lock, flags); + mutex_unlock(&clients_lock); list_for_each_entry(ism, &ism_dev_list.list, list) { spin_lock_irqsave(&ism->lock, flags); /* Stop forwarding IRQs and events */ @@ -571,21 +571,9 @@ static u64 ism_get_local_gid(struct ism_dev *ism) return ism->local_gid; } -static void ism_dev_add_work_func(struct work_struct *work) -{ - struct ism_client *client = container_of(work, struct ism_client, - add_work); - - client->add(client->tgt_ism); - ism_setup_forwarding(client, client->tgt_ism); - atomic_dec(&client->tgt_ism->add_dev_cnt); - wake_up(&client->tgt_ism->waitq); -} - static int ism_dev_init(struct ism_dev *ism) { struct pci_dev *pdev = ism->pdev; - unsigned long flags; int i, ret; ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSI); @@ -618,25 +606,16 @@ static int ism_dev_init(struct ism_dev *ism) /* hardware is V2 capable */ ism_create_system_eid(); - init_waitqueue_head(&ism->waitq); - atomic_set(&ism->free_clients_cnt, 0); - atomic_set(&ism->add_dev_cnt, 0); - - wait_event(ism->waitq, !atomic_read(&ism->add_dev_cnt)); - spin_lock_irqsave(&clients_lock, flags); - for (i = 0; i < max_client; ++i) - if (clients[i]) { - INIT_WORK(&clients[i]->add_work, - ism_dev_add_work_func); - clients[i]->tgt_ism = ism; - atomic_inc(&ism->add_dev_cnt); - schedule_work(&clients[i]->add_work); - } - spin_unlock_irqrestore(&clients_lock, flags); - - wait_event(ism->waitq, !atomic_read(&ism->add_dev_cnt)); - mutex_lock(&ism_dev_list.mutex); + mutex_lock(&clients_lock); + for (i = 0; i < max_client; ++i) { + if (clients[i]) { + clients[i]->add(ism); + ism_setup_forwarding(clients[i], ism); + } + } + mutex_unlock(&clients_lock); + list_add(&ism->list, &ism_dev_list.list); mutex_unlock(&ism_dev_list.mutex); @@ -711,40 +690,24 @@ static int ism_probe(struct pci_dev *pdev, const struct pci_device_id *id) return ret; } -static void ism_dev_remove_work_func(struct work_struct *work) -{ - struct ism_client *client = container_of(work, struct ism_client, - remove_work); - unsigned long flags; - - spin_lock_irqsave(&client->tgt_ism->lock, flags); - client->tgt_ism->subs[client->id] = NULL; - spin_unlock_irqrestore(&client->tgt_ism->lock, flags); - client->remove(client->tgt_ism); - atomic_dec(&client->tgt_ism->free_clients_cnt); - wake_up(&client->tgt_ism->waitq); -} - -/* Callers must hold ism_dev_list.mutex */ static void ism_dev_exit(struct ism_dev *ism) { struct pci_dev *pdev = ism->pdev; unsigned long flags; int i; - wait_event(ism->waitq, !atomic_read(&ism->free_clients_cnt)); - spin_lock_irqsave(&clients_lock, flags); + spin_lock_irqsave(&ism->lock, flags); for (i = 0; i < max_client; ++i) - if (clients[i]) { - INIT_WORK(&clients[i]->remove_work, - ism_dev_remove_work_func); - clients[i]->tgt_ism = ism; - atomic_inc(&ism->free_clients_cnt); - schedule_work(&clients[i]->remove_work); - } - spin_unlock_irqrestore(&clients_lock, flags); + ism->subs[i] = NULL; + spin_unlock_irqrestore(&ism->lock, flags); - wait_event(ism->waitq, !atomic_read(&ism->free_clients_cnt)); + mutex_lock(&ism_dev_list.mutex); + mutex_lock(&clients_lock); + for (i = 0; i < max_client; ++i) { + if (clients[i]) + clients[i]->remove(ism); + } + mutex_unlock(&clients_lock); if (SYSTEM_EID.serial_number[0] != '0' || SYSTEM_EID.type[0] != '0') @@ -755,15 +718,14 @@ static void ism_dev_exit(struct ism_dev *ism) kfree(ism->sba_client_arr); pci_free_irq_vectors(pdev); list_del_init(&ism->list); + mutex_unlock(&ism_dev_list.mutex); } static void ism_remove(struct pci_dev *pdev) { struct ism_dev *ism = dev_get_drvdata(&pdev->dev); - mutex_lock(&ism_dev_list.mutex); ism_dev_exit(ism); - mutex_unlock(&ism_dev_list.mutex); pci_release_mem_regions(pdev); pci_disable_device(pdev); diff --git a/include/linux/ism.h b/include/linux/ism.h index 5160d47e5ea9..9a4c204df3da 100644 --- a/include/linux/ism.h +++ b/include/linux/ism.h @@ -45,9 +45,6 @@ struct ism_dev { int ieq_idx; struct ism_client *subs[MAX_CLIENTS]; - atomic_t free_clients_cnt; - atomic_t add_dev_cnt; - wait_queue_head_t waitq; }; struct ism_event { @@ -69,9 +66,6 @@ struct ism_client { */ void (*handle_irq)(struct ism_dev *dev, unsigned int bit, u16 dmbemask); /* Private area - don't touch! */ - struct work_struct remove_work; - struct work_struct add_work; - struct ism_dev *tgt_ism; u8 id; }; From patchwork Fri Jul 7 10:43:59 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Niklas Schnelle X-Patchwork-Id: 13304720 X-Patchwork-Delegate: kuba@kernel.org Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 CF3A9BA47 for ; 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Fri, 7 Jul 2023 10:44:03 GMT Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DCEDE2006C; Fri, 7 Jul 2023 10:44:02 +0000 (GMT) Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 616AE20067; Fri, 7 Jul 2023 10:44:02 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTP; Fri, 7 Jul 2023 10:44:02 +0000 (GMT) From: Niklas Schnelle To: Paolo Abeni , Alexandra Winter , Wenjia Zhang , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Stefan Raspl , "David S. Miller" , Jan Karcher Cc: linux-s390@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net v2 3/3] s390/ism: Do not unregister clients with registered DMBs Date: Fri, 7 Jul 2023 12:43:59 +0200 Message-Id: <20230707104359.3324039-4-schnelle@linux.ibm.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230707104359.3324039-1-schnelle@linux.ibm.com> References: <20230707104359.3324039-1-schnelle@linux.ibm.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: MzfvT2oZq5ivVFuzWudenQfOz_mazAC- X-Proofpoint-GUID: OqOJMU7ONgozHh55kkrFxnHTPIudG_Ho X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.957,Hydra:6.0.591,FMLib:17.11.176.26 definitions=2023-07-07_06,2023-07-06_02,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 clxscore=1015 lowpriorityscore=0 adultscore=0 mlxlogscore=999 bulkscore=0 malwarescore=0 impostorscore=0 priorityscore=1501 spamscore=0 suspectscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2305260000 definitions=main-2307070097 X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org When ism_unregister_client() is called but the client still has DMBs registered it returns -EBUSY and prints an error. This only happens after the client has already been unregistered however. This is unexpected as the unregister claims to have failed. Furthermore as this implies a client bug a WARN() is more appropriate. Thus move the deregistration after the check and use WARN(). Fixes: 89e7d2ba61b7 ("net/ism: Add new API for client registration") Signed-off-by: Niklas Schnelle --- drivers/s390/net/ism_drv.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/drivers/s390/net/ism_drv.c b/drivers/s390/net/ism_drv.c index 54091b7aea16..6df7f377d2f9 100644 --- a/drivers/s390/net/ism_drv.c +++ b/drivers/s390/net/ism_drv.c @@ -96,29 +96,32 @@ int ism_unregister_client(struct ism_client *client) int rc = 0; mutex_lock(&ism_dev_list.mutex); - mutex_lock(&clients_lock); - clients[client->id] = NULL; - if (client->id + 1 == max_client) - max_client--; - mutex_unlock(&clients_lock); list_for_each_entry(ism, &ism_dev_list.list, list) { spin_lock_irqsave(&ism->lock, flags); /* Stop forwarding IRQs and events */ ism->subs[client->id] = NULL; for (int i = 0; i < ISM_NR_DMBS; ++i) { if (ism->sba_client_arr[i] == client->id) { - pr_err("%s: attempt to unregister client '%s'" - "with registered dmb(s)\n", __func__, - client->name); + WARN(1, "%s: attempt to unregister '%s' with registered dmb(s)\n", + __func__, client->name); rc = -EBUSY; - goto out; + goto err_reg_dmb; } } spin_unlock_irqrestore(&ism->lock, flags); } -out: mutex_unlock(&ism_dev_list.mutex); + mutex_lock(&clients_lock); + clients[client->id] = NULL; + if (client->id + 1 == max_client) + max_client--; + mutex_unlock(&clients_lock); + return rc; + +err_reg_dmb: + spin_unlock_irqrestore(&ism->lock, flags); + mutex_unlock(&ism_dev_list.mutex); return rc; } EXPORT_SYMBOL_GPL(ism_unregister_client);