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Commit 1c8f1da5 authored by Bharat Potnuri's avatar Bharat Potnuri Committed by Doug Ledford
Browse files

iw_cxgb4: Fix possible circular dependency locking warning 



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: default avatarPotnuri Bharat Teja <bharat@chelsio.com>
Reviewed-by: default avatarSteve Wise <swise@opengridcomputing.com>
Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
parent 84511455

drivers/infiniband/hw/cxgb4/device.c

+13 −15
Original line number Diff line number Diff line
@@ -64,14 +64,9 @@ module_param(c4iw_wr_log_size_order, int, 0444); 
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_rdev *rdev) 
	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 *handle, enum cxgb4_state new_state) 
	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 *handle, enum cxgb4_state new_state) 
				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);

drivers/infiniband/hw/cxgb4/iw_cxgb4.h

+9 −1
Original line number Diff line number Diff line
@@ -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);
@@ -988,7 +995,7 @@ void c4iw_rqtpool_destroy(struct c4iw_rdev *rdev); 
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);
@@ -1014,6 +1021,7 @@ struct ib_mr *c4iw_alloc_mr(struct ib_pd *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,

drivers/infiniband/hw/cxgb4/provider.c

+17 −9
Original line number Diff line number Diff line
@@ -531,10 +531,12 @@ static void get_dev_fw_str(struct ib_device *dev, char *str) 
		 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) 
	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 *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)