RDMA/core: Postpone uobject cleanup on failure till FD close

Remove the ib_is_destroyable_retryable() concept.

The idea here was to allow the drivers to forcibly clean the HW object
even if they otherwise didn't want to (eg because of usecnt). This was an
attempt to clean up in a world where drivers were not allowed to fail HW
object destruction.

Now that we are going back to allowing HW objects to fail destroy this
doesn't make sense. Instead if a uobject's HW object can't be destroyed it
is left on the uobject list and it is up to uverbs_destroy_ufile_hw() to
clean it. Multiple passes over the uobject list allow hidden dependencies
to be resolved. If that fails the HW driver is broken, throw a WARN_ON and
leak the HW object memory.

All the other tricky failure paths (eg on creation error unwind) have
already been updated to this new model.

Link: https://lore.kernel.org/r/20201104144556.3809085-2-leon@kernel.org
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

1 files changed, 2 insertions, 42 deletions

diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 9420827d2421..7e330f4a6d33 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -1471,6 +1471,8 @@ enum rdma_remove_reason {
 	RDMA_REMOVE_DRIVER_REMOVE,
 	/* uobj is being cleaned-up before being committed */
 	RDMA_REMOVE_ABORT,
+	/* The driver failed to destroy the uobject and is being disconnected */
+	RDMA_REMOVE_DRIVER_FAILURE,
 };
 
 struct ib_rdmacg_object {
@@ -1483,8 +1485,6 @@ struct ib_ucontext {
 	struct ib_device       *device;
 	struct ib_uverbs_file  *ufile;
 
-	bool cleanup_retryable;
-
 	struct ib_rdmacg_object	cg_obj;
 	/*
 	 * Implementation details of the RDMA core, don't use in drivers:
@@ -2904,46 +2904,6 @@ static inline bool ib_is_udata_cleared(struct ib_udata *udata,
 }
 
 /**
- * ib_is_destroy_retryable - Check whether the uobject destruction
- * is retryable.
- * @ret: The initial destruction return code
- * @why: remove reason
- * @uobj: The uobject that is destroyed
- *
- * This function is a helper function that IB layer and low-level drivers
- * can use to consider whether the destruction of the given uobject is
- * retry-able.
- * It checks the original return code, if it wasn't success the destruction
- * is retryable according to the ucontext state (i.e. cleanup_retryable) and
- * the remove reason. (i.e. why).
- * Must be called with the object locked for destroy.
- */
-static inline bool ib_is_destroy_retryable(int ret, enum rdma_remove_reason why,
-					   struct ib_uobject *uobj)
-{
-	return ret && (why == RDMA_REMOVE_DESTROY ||
-		       uobj->context->cleanup_retryable);
-}
-
-/**
- * ib_destroy_usecnt - Called during destruction to check the usecnt
- * @usecnt: The usecnt atomic
- * @why: remove reason
- * @uobj: The uobject that is destroyed
- *
- * Non-zero usecnts will block destruction unless destruction was triggered by
- * a ucontext cleanup.
- */
-static inline int ib_destroy_usecnt(atomic_t *usecnt,
-				    enum rdma_remove_reason why,
-				    struct ib_uobject *uobj)
-{
-	if (atomic_read(usecnt) && ib_is_destroy_retryable(-EBUSY, why, uobj))
-		return -EBUSY;
-	return 0;
-}
-
-/**
  * ib_modify_qp_is_ok - Check that the supplied attribute mask
  * contains all required attributes and no attributes not allowed for
  * the given QP state transition.