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path: root/drivers/infiniband/hw/mlx5/odp.c
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Diffstat (limited to 'drivers/infiniband/hw/mlx5/odp.c')
-rw-r--r--drivers/infiniband/hw/mlx5/odp.c58
1 files changed, 47 insertions, 11 deletions
diff --git a/drivers/infiniband/hw/mlx5/odp.c b/drivers/infiniband/hw/mlx5/odp.c
index 2e9b43061797..3f9478d19376 100644
--- a/drivers/infiniband/hw/mlx5/odp.c
+++ b/drivers/infiniband/hw/mlx5/odp.c
@@ -178,6 +178,29 @@ void mlx5_odp_populate_klm(struct mlx5_klm *pklm, size_t offset,
return;
}
+ /*
+ * The locking here is pretty subtle. Ideally the implicit children
+ * list would be protected by the umem_mutex, however that is not
+ * possible. Instead this uses a weaker update-then-lock pattern:
+ *
+ * srcu_read_lock()
+ * <change children list>
+ * mutex_lock(umem_mutex)
+ * mlx5_ib_update_xlt()
+ * mutex_unlock(umem_mutex)
+ * destroy lkey
+ *
+ * ie any change the children list must be followed by the locked
+ * update_xlt before destroying.
+ *
+ * The umem_mutex provides the acquire/release semantic needed to make
+ * the children list visible to a racing thread. While SRCU is not
+ * technically required, using it gives consistent use of the SRCU
+ * locking around the children list.
+ */
+ lockdep_assert_held(&to_ib_umem_odp(mr->umem)->umem_mutex);
+ lockdep_assert_held(&mr->dev->mr_srcu);
+
odp = odp_lookup(offset * MLX5_IMR_MTT_SIZE,
nentries * MLX5_IMR_MTT_SIZE, mr);
@@ -202,15 +225,22 @@ static void mr_leaf_free_action(struct work_struct *work)
struct ib_umem_odp *odp = container_of(work, struct ib_umem_odp, work);
int idx = ib_umem_start(odp) >> MLX5_IMR_MTT_SHIFT;
struct mlx5_ib_mr *mr = odp->private, *imr = mr->parent;
+ struct ib_umem_odp *odp_imr = to_ib_umem_odp(imr->umem);
+ int srcu_key;
mr->parent = NULL;
synchronize_srcu(&mr->dev->mr_srcu);
- ib_umem_odp_release(odp);
- if (imr->live)
+ if (smp_load_acquire(&imr->live)) {
+ srcu_key = srcu_read_lock(&mr->dev->mr_srcu);
+ mutex_lock(&odp_imr->umem_mutex);
mlx5_ib_update_xlt(imr, idx, 1, 0,
MLX5_IB_UPD_XLT_INDIRECT |
MLX5_IB_UPD_XLT_ATOMIC);
+ mutex_unlock(&odp_imr->umem_mutex);
+ srcu_read_unlock(&mr->dev->mr_srcu, srcu_key);
+ }
+ ib_umem_odp_release(odp);
mlx5_mr_cache_free(mr->dev, mr);
if (atomic_dec_and_test(&imr->num_leaf_free))
@@ -278,7 +308,6 @@ void mlx5_ib_invalidate_range(struct ib_umem_odp *umem_odp, unsigned long start,
idx - blk_start_idx + 1, 0,
MLX5_IB_UPD_XLT_ZAP |
MLX5_IB_UPD_XLT_ATOMIC);
- mutex_unlock(&umem_odp->umem_mutex);
/*
* We are now sure that the device will not access the
* memory. We can safely unmap it, and mark it as dirty if
@@ -289,10 +318,12 @@ void mlx5_ib_invalidate_range(struct ib_umem_odp *umem_odp, unsigned long start,
if (unlikely(!umem_odp->npages && mr->parent &&
!umem_odp->dying)) {
- WRITE_ONCE(umem_odp->dying, 1);
+ WRITE_ONCE(mr->live, 0);
+ umem_odp->dying = 1;
atomic_inc(&mr->parent->num_leaf_free);
schedule_work(&umem_odp->work);
}
+ mutex_unlock(&umem_odp->umem_mutex);
}
void mlx5_ib_internal_fill_odp_caps(struct mlx5_ib_dev *dev)
@@ -429,8 +460,6 @@ static struct mlx5_ib_mr *implicit_mr_alloc(struct ib_pd *pd,
mr->ibmr.lkey = mr->mmkey.key;
mr->ibmr.rkey = mr->mmkey.key;
- mr->live = 1;
-
mlx5_ib_dbg(dev, "key %x dev %p mr %p\n",
mr->mmkey.key, dev->mdev, mr);
@@ -484,6 +513,8 @@ next_mr:
mtt->parent = mr;
INIT_WORK(&odp->work, mr_leaf_free_action);
+ smp_store_release(&mtt->live, 1);
+
if (!nentries)
start_idx = addr >> MLX5_IMR_MTT_SHIFT;
nentries++;
@@ -536,6 +567,7 @@ struct mlx5_ib_mr *mlx5_ib_alloc_implicit_mr(struct mlx5_ib_pd *pd,
init_waitqueue_head(&imr->q_leaf_free);
atomic_set(&imr->num_leaf_free, 0);
atomic_set(&imr->num_pending_prefetch, 0);
+ smp_store_release(&imr->live, 1);
return imr;
}
@@ -555,15 +587,19 @@ void mlx5_ib_free_implicit_mr(struct mlx5_ib_mr *imr)
if (mr->parent != imr)
continue;
+ mutex_lock(&umem_odp->umem_mutex);
ib_umem_odp_unmap_dma_pages(umem_odp, ib_umem_start(umem_odp),
ib_umem_end(umem_odp));
- if (umem_odp->dying)
+ if (umem_odp->dying) {
+ mutex_unlock(&umem_odp->umem_mutex);
continue;
+ }
- WRITE_ONCE(umem_odp->dying, 1);
+ umem_odp->dying = 1;
atomic_inc(&imr->num_leaf_free);
schedule_work(&umem_odp->work);
+ mutex_unlock(&umem_odp->umem_mutex);
}
up_read(&per_mm->umem_rwsem);
@@ -773,7 +809,7 @@ next_mr:
switch (mmkey->type) {
case MLX5_MKEY_MR:
mr = container_of(mmkey, struct mlx5_ib_mr, mmkey);
- if (!mr->live || !mr->ibmr.pd) {
+ if (!smp_load_acquire(&mr->live) || !mr->ibmr.pd) {
mlx5_ib_dbg(dev, "got dead MR\n");
ret = -EFAULT;
goto srcu_unlock;
@@ -1641,12 +1677,12 @@ static bool num_pending_prefetch_inc(struct ib_pd *pd,
mr = container_of(mmkey, struct mlx5_ib_mr, mmkey);
- if (mr->ibmr.pd != pd) {
+ if (!smp_load_acquire(&mr->live)) {
ret = false;
break;
}
- if (!mr->live) {
+ if (mr->ibmr.pd != pd) {
ret = false;
break;
}