Commit eb73060b authored by Jason Gunthorpe's avatar Jason Gunthorpe
Browse files

RDMA/cm: Make the local_id_table xarray non-irq 

The xarray is never mutated from an IRQ handler, only from work queues
under a spinlock_irq. Thus there is no reason for it be an IRQ type
xarray.

This was copied over from the original IDR code, but the recent rework put
the xarray inside another spinlock_irq which will unbalance the unlocking.

Fixes: c206f8ba ("RDMA/cm: Make it clearer how concurrency works in cm_req_handler()")
Link: https://lore.kernel.org/r/0-v1-808b6da3bd3f+1857-cm_xarray_no_irq_jgg@nvidia.com


Reported-by: default avatarMatthew Wilcox <willy@infradead.org>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent f8394f23

drivers/infiniband/core/cm.c

+6 −6
Original line number Diff line number Diff line
@@ -859,7 +859,7 @@ static struct cm_id_private *cm_alloc_id_priv(struct ib_device *device, 
	atomic_set(&cm_id_priv->work_count, -1);

	refcount_set(&cm_id_priv->refcount, 1);



	ret = xa_alloc_cyclic_irq(&cm.local_id_table, &id, NULL, xa_limit_32b,

	ret = xa_alloc_cyclic(&cm.local_id_table, &id, NULL, xa_limit_32b,

			      &cm.local_id_next, GFP_KERNEL);

	if (ret < 0)

		goto error;
@@ -878,8 +878,8 @@ error: 
 */

static void cm_finalize_id(struct cm_id_private *cm_id_priv)

{

	xa_store_irq(&cm.local_id_table, cm_local_id(cm_id_priv->id.local_id),

		     cm_id_priv, GFP_KERNEL);

	xa_store(&cm.local_id_table, cm_local_id(cm_id_priv->id.local_id),

		 cm_id_priv, GFP_ATOMIC);

}



struct ib_cm_id *ib_create_cm_id(struct ib_device *device,
@@ -1169,7 +1169,7 @@ retest: 
	spin_unlock(&cm.lock);

	spin_unlock_irq(&cm_id_priv->lock);



	xa_erase_irq(&cm.local_id_table, cm_local_id(cm_id->local_id));

	xa_erase(&cm.local_id_table, cm_local_id(cm_id->local_id));

	cm_deref_id(cm_id_priv);

	wait_for_completion(&cm_id_priv->comp);

	while ((work = cm_dequeue_work(cm_id_priv)) != NULL)
@@ -4482,7 +4482,7 @@ static int __init ib_cm_init(void) 
	cm.remote_id_table = RB_ROOT;

	cm.remote_qp_table = RB_ROOT;

	cm.remote_sidr_table = RB_ROOT;

	xa_init_flags(&cm.local_id_table, XA_FLAGS_ALLOC | XA_FLAGS_LOCK_IRQ);

	xa_init_flags(&cm.local_id_table, XA_FLAGS_ALLOC);

	get_random_bytes(&cm.random_id_operand, sizeof cm.random_id_operand);

	INIT_LIST_HEAD(&cm.timewait_list);

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