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: c206f8bad15d ("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: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
index 5740d1ba3568700759290d907560f27148e9dc21..012156624b8299a11f38bcda378505240cc96a42 100644 (file)
--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -859,8 +859,8 @@ 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,
-                                 &cm.local_id_next, GFP_KERNEL);
+       ret = xa_alloc_cyclic(&cm.local_id_table, &id, NULL, xa_limit_32b,
+                             &cm.local_id_next, GFP_KERNEL);
        if (ret < 0)
                goto error;
        cm_id_priv->id.local_id = (__force __be32)id ^ cm.random_id_operand;
@@ -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);