RDMA/rxe: Convert read side locking to rcu

Use rcu_read_lock() for protecting read side operations in rxe_pool.c.

Link: https://lore.kernel.org/r/20220612223434.31462-3-rpearsonhpe@gmail.com
Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/drivers/infiniband/sw/rxe/rxe_pool.c b/drivers/infiniband/sw/rxe/rxe_pool.c
index 74eca7f..f50620f 100644 (file)
--- a/drivers/infiniband/sw/rxe/rxe_pool.c
+++ b/drivers/infiniband/sw/rxe/rxe_pool.c
@@ -197,16 +197,15 @@ void *rxe_pool_get_index(struct rxe_pool *pool, u32 index)
 {
        struct rxe_pool_elem *elem;
        struct xarray *xa = &pool->xa;
-       unsigned long flags;
        void *obj;
 
-       xa_lock_irqsave(xa, flags);
+       rcu_read_lock();
        elem = xa_load(xa, index);
        if (elem && kref_get_unless_zero(&elem->ref_cnt))
                obj = elem->obj;
        else
                obj = NULL;
-       xa_unlock_irqrestore(xa, flags);
+       rcu_read_unlock();
 
        return obj;
 }
@@ -223,7 +222,6 @@ int __rxe_cleanup(struct rxe_pool_elem *elem, bool sleepable)
        struct rxe_pool *pool = elem->pool;
        struct xarray *xa = &pool->xa;
        static int timeout = RXE_POOL_TIMEOUT;
-       unsigned long flags;
        int ret, err = 0;
        void *xa_ret;
 
@@ -233,9 +231,7 @@ int __rxe_cleanup(struct rxe_pool_elem *elem, bool sleepable)
        /* erase xarray entry to prevent looking up
         * the pool elem from its index
         */
-       xa_lock_irqsave(xa, flags);
-       xa_ret = __xa_erase(xa, elem->index);
-       xa_unlock_irqrestore(xa, flags);
+       xa_ret = xa_erase(xa, elem->index);
        WARN_ON(xa_err(xa_ret));
 
        /* if this is the last call to rxe_put complete the
@@ -280,7 +276,7 @@ int __rxe_cleanup(struct rxe_pool_elem *elem, bool sleepable)
                pool->cleanup(elem);
 
        if (pool->type == RXE_TYPE_MR)
-               kfree(elem->obj);
+               kfree_rcu(elem->obj);
 
        atomic_dec(&pool->num_elem);
 
@@ -299,12 +295,8 @@ int __rxe_put(struct rxe_pool_elem *elem)
 
 void __rxe_finalize(struct rxe_pool_elem *elem)
 {
-       struct xarray *xa = &elem->pool->xa;
-       unsigned long flags;
-       void *ret;
-
-       xa_lock_irqsave(xa, flags);
-       ret = __xa_store(&elem->pool->xa, elem->index, elem, GFP_KERNEL);
-       xa_unlock_irqrestore(xa, flags);
-       WARN_ON(xa_err(ret));
+       void *xa_ret;
+
+       xa_ret = xa_store(&elem->pool->xa, elem->index, elem, GFP_KERNEL);
+       WARN_ON(xa_err(xa_ret));
 }