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[2.111.91.225]) by smtp.gmail.com with ESMTPSA id q21sm1050260lfa.84.2019.05.04.11.38.48 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 04 May 2019 11:38:48 -0700 (PDT) From: =?utf-8?q?Matias_Bj=C3=B8rling?= To: axboe@fb.com Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, Igor Konopko , =?utf-8?q?Matias_Bj=C3=B8rling?= Subject: [GIT PULL 23/26] lightnvm: track inflight target creations Date: Sat, 4 May 2019 20:38:08 +0200 Message-Id: <20190504183811.18725-24-mb@lightnvm.io> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190504183811.18725-1-mb@lightnvm.io> References: <20190504183811.18725-1-mb@lightnvm.io> MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Igor Konopko When creation process is still in progress, target is not yet on targets list. This causes a chance for removing whole lightnvm subsystem by calling nvm_unregister() in the meantime and finally by causing kernel panic inside target init function. This patch changes the behaviour by adding kref variable which tracks all the users of nvm_dev structure. When nvm_dev is allocated, kref value is set to 1. Then before every target creation the value is increased and decreased after target removal. The extra reference is decreased when nvm subsystem is unregistered. Signed-off-by: Igor Konopko Reviewed-by: Javier González Signed-off-by: Matias Bjørling --- drivers/lightnvm/core.c | 41 ++++++++++++++++++++++++++++++---------- include/linux/lightnvm.h | 1 + 2 files changed, 32 insertions(+), 10 deletions(-) diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c index e2abe88a139c..0e9f7996ff1d 100644 --- a/drivers/lightnvm/core.c +++ b/drivers/lightnvm/core.c @@ -45,6 +45,8 @@ struct nvm_dev_map { int num_ch; }; +static void nvm_free(struct kref *ref); + static struct nvm_target *nvm_find_target(struct nvm_dev *dev, const char *name) { struct nvm_target *tgt; @@ -501,6 +503,7 @@ static int nvm_remove_tgt(struct nvm_dev *dev, struct nvm_ioctl_remove *remove) } __nvm_remove_target(t, true); mutex_unlock(&dev->mlock); + kref_put(&dev->ref, nvm_free); return 0; } @@ -1094,15 +1097,16 @@ static int nvm_core_init(struct nvm_dev *dev) return ret; } -static void nvm_free(struct nvm_dev *dev) +static void nvm_free(struct kref *ref) { - if (!dev) - return; + struct nvm_dev *dev = container_of(ref, struct nvm_dev, ref); if (dev->dma_pool) dev->ops->destroy_dma_pool(dev->dma_pool); - nvm_unregister_map(dev); + if (dev->rmap) + nvm_unregister_map(dev); + kfree(dev->lun_map); kfree(dev); } @@ -1139,7 +1143,13 @@ static int nvm_init(struct nvm_dev *dev) struct nvm_dev *nvm_alloc_dev(int node) { - return kzalloc_node(sizeof(struct nvm_dev), GFP_KERNEL, node); + struct nvm_dev *dev; + + dev = kzalloc_node(sizeof(struct nvm_dev), GFP_KERNEL, node); + if (dev) + kref_init(&dev->ref); + + return dev; } EXPORT_SYMBOL(nvm_alloc_dev); @@ -1147,12 +1157,16 @@ int nvm_register(struct nvm_dev *dev) { int ret, exp_pool_size; - if (!dev->q || !dev->ops) + if (!dev->q || !dev->ops) { + kref_put(&dev->ref, nvm_free); return -EINVAL; + } ret = nvm_init(dev); - if (ret) + if (ret) { + kref_put(&dev->ref, nvm_free); return ret; + } exp_pool_size = max_t(int, PAGE_SIZE, (NVM_MAX_VLBA * (sizeof(u64) + dev->geo.sos))); @@ -1162,7 +1176,7 @@ int nvm_register(struct nvm_dev *dev) exp_pool_size); if (!dev->dma_pool) { pr_err("nvm: could not create dma pool\n"); - nvm_free(dev); + kref_put(&dev->ref, nvm_free); return -ENOMEM; } @@ -1184,6 +1198,7 @@ void nvm_unregister(struct nvm_dev *dev) if (t->dev->parent != dev) continue; __nvm_remove_target(t, false); + kref_put(&dev->ref, nvm_free); } mutex_unlock(&dev->mlock); @@ -1191,13 +1206,14 @@ void nvm_unregister(struct nvm_dev *dev) list_del(&dev->devices); up_write(&nvm_lock); - nvm_free(dev); + kref_put(&dev->ref, nvm_free); } EXPORT_SYMBOL(nvm_unregister); static int __nvm_configure_create(struct nvm_ioctl_create *create) { struct nvm_dev *dev; + int ret; down_write(&nvm_lock); dev = nvm_find_nvm_dev(create->dev); @@ -1208,7 +1224,12 @@ static int __nvm_configure_create(struct nvm_ioctl_create *create) return -EINVAL; } - return nvm_create_tgt(dev, create); + kref_get(&dev->ref); + ret = nvm_create_tgt(dev, create); + if (ret) + kref_put(&dev->ref, nvm_free); + + return ret; } static long nvm_ioctl_info(struct file *file, void __user *arg) diff --git a/include/linux/lightnvm.h b/include/linux/lightnvm.h index d3b02708e5f0..4d0d5655c7b2 100644 --- a/include/linux/lightnvm.h +++ b/include/linux/lightnvm.h @@ -428,6 +428,7 @@ struct nvm_dev { char name[DISK_NAME_LEN]; void *private_data; + struct kref ref; void *rmap; struct mutex mlock;