From: Anish Bhatt Date: Tue, 16 Sep 2014 00:44:18 +0000 (-0700) Subject: [SCSI] cxgb4i: avoid holding mutex in interrupt context X-Git-Tag: v3.17~1^2~1 X-Git-Url: http://git.cascardo.eti.br/?a=commitdiff_plain;h=078efae00ffc76381c3248006e9cf0988163488f;p=cascardo%2Flinux.git [SCSI] cxgb4i: avoid holding mutex in interrupt context cxgbi_inet6addr_handler() can be called in interrupt context, so use rcu protected list while finding netdev. This is observed as a scheduling in atomic oops when running over ipv6. Fixes: fc8d0590d914 ("libcxgbi: Add ipv6 api to driver") Fixes: 759a0cc5a3e1 ("cxgb4i: Add ipv6 code to driver, call into libcxgbi ipv6 api") Signed-off-by: Anish Bhatt Signed-off-by: Karen Xie Signed-off-by: Christoph Hellwig Signed-off-by: James Bottomley --- diff --git a/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c b/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c index 79788a12712d..02e69e7ee4a3 100644 --- a/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c +++ b/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c @@ -1647,7 +1647,7 @@ static int cxgbi_inet6addr_handler(struct notifier_block *this, if (event_dev->priv_flags & IFF_802_1Q_VLAN) event_dev = vlan_dev_real_dev(event_dev); - cdev = cxgbi_device_find_by_netdev(event_dev, NULL); + cdev = cxgbi_device_find_by_netdev_rcu(event_dev, NULL); if (!cdev) return ret; diff --git a/drivers/scsi/cxgbi/libcxgbi.c b/drivers/scsi/cxgbi/libcxgbi.c index d65df6dc106f..addd1dddce14 100644 --- a/drivers/scsi/cxgbi/libcxgbi.c +++ b/drivers/scsi/cxgbi/libcxgbi.c @@ -57,6 +57,9 @@ MODULE_PARM_DESC(dbg_level, "libiscsi debug level (default=0)"); static LIST_HEAD(cdev_list); static DEFINE_MUTEX(cdev_mutex); +static LIST_HEAD(cdev_rcu_list); +static DEFINE_SPINLOCK(cdev_rcu_lock); + int cxgbi_device_portmap_create(struct cxgbi_device *cdev, unsigned int base, unsigned int max_conn) { @@ -142,6 +145,10 @@ struct cxgbi_device *cxgbi_device_register(unsigned int extra, list_add_tail(&cdev->list_head, &cdev_list); mutex_unlock(&cdev_mutex); + spin_lock(&cdev_rcu_lock); + list_add_tail_rcu(&cdev->rcu_node, &cdev_rcu_list); + spin_unlock(&cdev_rcu_lock); + log_debug(1 << CXGBI_DBG_DEV, "cdev 0x%p, p# %u.\n", cdev, nports); return cdev; @@ -153,9 +160,16 @@ void cxgbi_device_unregister(struct cxgbi_device *cdev) log_debug(1 << CXGBI_DBG_DEV, "cdev 0x%p, p# %u,%s.\n", cdev, cdev->nports, cdev->nports ? cdev->ports[0]->name : ""); + mutex_lock(&cdev_mutex); list_del(&cdev->list_head); mutex_unlock(&cdev_mutex); + + spin_lock(&cdev_rcu_lock); + list_del_rcu(&cdev->rcu_node); + spin_unlock(&cdev_rcu_lock); + synchronize_rcu(); + cxgbi_device_destroy(cdev); } EXPORT_SYMBOL_GPL(cxgbi_device_unregister); @@ -167,12 +181,9 @@ void cxgbi_device_unregister_all(unsigned int flag) mutex_lock(&cdev_mutex); list_for_each_entry_safe(cdev, tmp, &cdev_list, list_head) { if ((cdev->flags & flag) == flag) { - log_debug(1 << CXGBI_DBG_DEV, - "cdev 0x%p, p# %u,%s.\n", - cdev, cdev->nports, cdev->nports ? - cdev->ports[0]->name : ""); - list_del(&cdev->list_head); - cxgbi_device_destroy(cdev); + mutex_unlock(&cdev_mutex); + cxgbi_device_unregister(cdev); + mutex_lock(&cdev_mutex); } } mutex_unlock(&cdev_mutex); @@ -191,6 +202,7 @@ struct cxgbi_device *cxgbi_device_find_by_lldev(void *lldev) } } mutex_unlock(&cdev_mutex); + log_debug(1 << CXGBI_DBG_DEV, "lldev 0x%p, NO match found.\n", lldev); return NULL; @@ -230,6 +242,39 @@ struct cxgbi_device *cxgbi_device_find_by_netdev(struct net_device *ndev, } EXPORT_SYMBOL_GPL(cxgbi_device_find_by_netdev); +struct cxgbi_device *cxgbi_device_find_by_netdev_rcu(struct net_device *ndev, + int *port) +{ + struct net_device *vdev = NULL; + struct cxgbi_device *cdev; + int i; + + if (ndev->priv_flags & IFF_802_1Q_VLAN) { + vdev = ndev; + ndev = vlan_dev_real_dev(ndev); + pr_info("vlan dev %s -> %s.\n", vdev->name, ndev->name); + } + + rcu_read_lock(); + list_for_each_entry_rcu(cdev, &cdev_rcu_list, rcu_node) { + for (i = 0; i < cdev->nports; i++) { + if (ndev == cdev->ports[i]) { + cdev->hbas[i]->vdev = vdev; + rcu_read_unlock(); + if (port) + *port = i; + return cdev; + } + } + } + rcu_read_unlock(); + + log_debug(1 << CXGBI_DBG_DEV, + "ndev 0x%p, %s, NO match found.\n", ndev, ndev->name); + return NULL; +} +EXPORT_SYMBOL_GPL(cxgbi_device_find_by_netdev_rcu); + static struct cxgbi_device *cxgbi_device_find_by_mac(struct net_device *ndev, int *port) { diff --git a/drivers/scsi/cxgbi/libcxgbi.h b/drivers/scsi/cxgbi/libcxgbi.h index b3e6e7541cc5..1d98fad6a0ab 100644 --- a/drivers/scsi/cxgbi/libcxgbi.h +++ b/drivers/scsi/cxgbi/libcxgbi.h @@ -527,6 +527,7 @@ struct cxgbi_ports_map { #define CXGBI_FLAG_IPV4_SET 0x10 struct cxgbi_device { struct list_head list_head; + struct list_head rcu_node; unsigned int flags; struct net_device **ports; void *lldev; @@ -709,6 +710,8 @@ void cxgbi_device_unregister(struct cxgbi_device *); void cxgbi_device_unregister_all(unsigned int flag); struct cxgbi_device *cxgbi_device_find_by_lldev(void *); struct cxgbi_device *cxgbi_device_find_by_netdev(struct net_device *, int *); +struct cxgbi_device *cxgbi_device_find_by_netdev_rcu(struct net_device *, + int *); int cxgbi_hbas_add(struct cxgbi_device *, u64, unsigned int, struct scsi_host_template *, struct scsi_transport_template *);