From: Bharat Potnuri <bharat@chelsio.com>
Date: Thu, 9 Nov 2017 17:47:33 +0530
Subject: iw_cxgb4: Fix possible circular dependency locking warning
Patch-mainline: v4.15-rc1
Git-commit: 1c8f1da5d851b92aeb81dbbb9ebd516f6e2588f5
References: bsc#1064802 bsc#1066129
Locking sequence of iw_cxgb4 and RoCE drivers in ib_register_device() is
slightly different and this leads to possible circular dependency locking
warning when both the devices are brought up.
Here is the locking sequence upto ib_register_device():
iw_cxgb4: rtnl_mutex(net stack) --> uld_mutex --> device_mutex
RoCE drivers: device_mutex --> rtnl_mutex
Here is the possibility of cross locking:
CPU #0 (iw_cxgb4) CPU #1 (RoCE drivers)
-> on interface up cxgb4_up()
executed with rtnl_mutex held
-> hold uld_mutex and try
registering ib device
-> In ib_register_device() hold
device_mutex
-> hold device mutex in
ib_register_device
-> try acquiring rtnl_mutex in
ib_enum_roce_netdev()
Current patch schedules the ib_register_device() functionality of
iw_cxgb4 to a workqueue to prevent the possible cross-locking.
Also rename the labels in c4iw_reister_device().
Signed-off-by: Potnuri Bharat Teja <bharat@chelsio.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/infiniband/hw/cxgb4/device.c | 28 +++++++++++++---------------
drivers/infiniband/hw/cxgb4/iw_cxgb4.h | 10 +++++++++-
drivers/infiniband/hw/cxgb4/provider.c | 26 +++++++++++++++++---------
3 files changed, 39 insertions(+), 25 deletions(-)
--- a/drivers/infiniband/hw/cxgb4/device.c
+++ b/drivers/infiniband/hw/cxgb4/device.c
@@ -64,14 +64,9 @@ module_param(c4iw_wr_log_size_order, int
MODULE_PARM_DESC(c4iw_wr_log_size_order,
"Number of entries (log2) in the work request timing log.");
-struct uld_ctx {
- struct list_head entry;
- struct cxgb4_lld_info lldi;
- struct c4iw_dev *dev;
-};
-
static LIST_HEAD(uld_ctx_list);
static DEFINE_MUTEX(dev_mutex);
+struct workqueue_struct *reg_workq;
#define DB_FC_RESUME_SIZE 64
#define DB_FC_RESUME_DELAY 1
@@ -912,7 +907,7 @@ static void c4iw_rdev_close(struct c4iw_
c4iw_destroy_resource(&rdev->resource);
}
-static void c4iw_dealloc(struct uld_ctx *ctx)
+void c4iw_dealloc(struct uld_ctx *ctx)
{
c4iw_rdev_close(&ctx->dev->rdev);
WARN_ON_ONCE(!idr_is_empty(&ctx->dev->cqidr));
@@ -1208,8 +1203,6 @@ static int c4iw_uld_state_change(void *h
case CXGB4_STATE_UP:
pr_info("%s: Up\n", pci_name(ctx->lldi.pdev));
if (!ctx->dev) {
- int ret;
-
ctx->dev = c4iw_alloc(&ctx->lldi);
if (IS_ERR(ctx->dev)) {
pr_err("%s: initialization failed: %ld\n",
@@ -1218,12 +1211,9 @@ static int c4iw_uld_state_change(void *h
ctx->dev = NULL;
break;
}
- ret = c4iw_register_device(ctx->dev);
- if (ret) {
- pr_err("%s: RDMA registration failed: %d\n",
- pci_name(ctx->lldi.pdev), ret);
- c4iw_dealloc(ctx);
- }
+
+ INIT_WORK(&ctx->reg_work, c4iw_register_device);
+ queue_work(reg_workq, &ctx->reg_work);
}
break;
case CXGB4_STATE_DOWN:
@@ -1551,6 +1541,12 @@ static int __init c4iw_init_module(void)
if (!c4iw_debugfs_root)
pr_warn("could not create debugfs entry, continuing\n");
+ reg_workq = create_singlethread_workqueue("Register_iWARP_device");
+ if (!reg_workq) {
+ pr_err("Failed creating workqueue to register iwarp device\n");
+ return -ENOMEM;
+ }
+
cxgb4_register_uld(CXGB4_ULD_RDMA, &c4iw_uld_info);
return 0;
@@ -1567,6 +1563,8 @@ static void __exit c4iw_exit_module(void
kfree(ctx);
}
mutex_unlock(&dev_mutex);
+ flush_workqueue(reg_workq);
+ destroy_workqueue(reg_workq);
cxgb4_unregister_uld(CXGB4_ULD_RDMA);
c4iw_cm_term();
debugfs_remove_recursive(c4iw_debugfs_root);
--- a/drivers/infiniband/hw/cxgb4/iw_cxgb4.h
+++ b/drivers/infiniband/hw/cxgb4/iw_cxgb4.h
@@ -322,6 +322,13 @@ struct c4iw_dev {
wait_queue_head_t wait;
};
+struct uld_ctx {
+ struct list_head entry;
+ struct cxgb4_lld_info lldi;
+ struct c4iw_dev *dev;
+ struct work_struct reg_work;
+};
+
static inline struct c4iw_dev *to_c4iw_dev(struct ib_device *ibdev)
{
return container_of(ibdev, struct c4iw_dev, ibdev);
@@ -989,7 +996,7 @@ void c4iw_rqtpool_destroy(struct c4iw_rd
void c4iw_ocqp_pool_destroy(struct c4iw_rdev *rdev);
void c4iw_destroy_resource(struct c4iw_resource *rscp);
int c4iw_destroy_ctrl_qp(struct c4iw_rdev *rdev);
-int c4iw_register_device(struct c4iw_dev *dev);
+void c4iw_register_device(struct work_struct *work);
void c4iw_unregister_device(struct c4iw_dev *dev);
int __init c4iw_cm_init(void);
void c4iw_cm_term(void);
@@ -1015,6 +1022,7 @@ struct ib_mr *c4iw_alloc_mr(struct ib_pd
int c4iw_map_mr_sg(struct ib_mr *ibmr, struct scatterlist *sg, int sg_nents,
unsigned int *sg_offset);
int c4iw_dealloc_mw(struct ib_mw *mw);
+void c4iw_dealloc(struct uld_ctx *ctx);
struct ib_mw *c4iw_alloc_mw(struct ib_pd *pd, enum ib_mw_type type,
struct ib_udata *udata);
struct ib_mr *c4iw_reg_user_mr(struct ib_pd *pd, u64 start,
--- a/drivers/infiniband/hw/cxgb4/provider.c
+++ b/drivers/infiniband/hw/cxgb4/provider.c
@@ -531,10 +531,12 @@ static void get_dev_fw_str(struct ib_dev
FW_HDR_FW_VER_BUILD_G(c4iw_dev->rdev.lldi.fw_vers));
}
-int c4iw_register_device(struct c4iw_dev *dev)
+void c4iw_register_device(struct work_struct *work)
{
int ret;
int i;
+ struct uld_ctx *ctx = container_of(work, struct uld_ctx, reg_work);
+ struct c4iw_dev *dev = ctx->dev;
pr_debug("c4iw_dev %p\n", dev);
strlcpy(dev->ibdev.name, "cxgb4_%d", IB_DEVICE_NAME_MAX);
@@ -609,8 +611,10 @@ int c4iw_register_device(struct c4iw_dev
dev->ibdev.get_dev_fw_str = get_dev_fw_str;
dev->ibdev.iwcm = kmalloc(sizeof(struct iw_cm_verbs), GFP_KERNEL);
- if (!dev->ibdev.iwcm)
- return -ENOMEM;
+ if (!dev->ibdev.iwcm) {
+ ret = -ENOMEM;
+ goto err_dealloc_ctx;
+ }
dev->ibdev.iwcm->connect = c4iw_connect;
dev->ibdev.iwcm->accept = c4iw_accept_cr;
@@ -625,20 +629,24 @@ int c4iw_register_device(struct c4iw_dev
ret = ib_register_device(&dev->ibdev, NULL);
if (ret)
- goto bail1;
+ goto err_kfree_iwcm;
for (i = 0; i < ARRAY_SIZE(c4iw_class_attributes); ++i) {
ret = device_create_file(&dev->ibdev.dev,
c4iw_class_attributes[i]);
if (ret)
- goto bail2;
+ goto err_unregister_device;
}
- return 0;
-bail2:
+ return;
+err_unregister_device:
ib_unregister_device(&dev->ibdev);
-bail1:
+err_kfree_iwcm:
kfree(dev->ibdev.iwcm);
- return ret;
+err_dealloc_ctx:
+ pr_err("%s - Failed registering iwarp device: %d\n",
+ pci_name(ctx->lldi.pdev), ret);
+ c4iw_dealloc(ctx);
+ return;
}
void c4iw_unregister_device(struct c4iw_dev *dev)