git: 9fe9a92ab68f - stable/13 - ibcore: Add some functions and definitions for selecting and querying retryable ucontext cleanup.

[Hans Petter Selasky]

The branch stable/13 has been updated by hselasky:

URL: https://cgit.FreeBSD.org/src/commit/?id=9fe9a92ab68fc3f8aa0b6a45f46e2385cc10887f

commit 9fe9a92ab68fc3f8aa0b6a45f46e2385cc10887f
Author:     Hans Petter Selasky <hselasky at FreeBSD.org>
AuthorDate: 2021-06-16 13:02:00 +0000
Commit:     Hans Petter Selasky <hselasky at FreeBSD.org>
CommitDate: 2021-07-26 16:04:33 +0000

    ibcore: Add some functions and definitions for selecting and querying retryable ucontext cleanup.
    
    Linux commit:
    1c77483e4c50339b0306572167ccbff6b55d051b
    
    Reviewed by:    kib
    Sponsored by:   Mellanox Technologies // NVIDIA Networking
    
    (cherry picked from commit f60da09dbb152d7c8ee1719197d98149a8b0c017)
---
 sys/ofed/drivers/infiniband/core/ib_uverbs_cmd.c |  1 +
 sys/ofed/include/rdma/ib_verbs.h                 | 56 ++++++++++++++++++++++++
 2 files changed, 57 insertions(+)

diff --git a/sys/ofed/drivers/infiniband/core/ib_uverbs_cmd.c b/sys/ofed/drivers/infiniband/core/ib_uverbs_cmd.c
index ab6e27d40d33..df3f8657755c 100644
--- a/sys/ofed/drivers/infiniband/core/ib_uverbs_cmd.c
+++ b/sys/ofed/drivers/infiniband/core/ib_uverbs_cmd.c
@@ -365,6 +365,7 @@ ssize_t ib_uverbs_get_context(struct ib_uverbs_file *file,
 	ucontext->tgid = get_pid(task_pid_group_leader(current));
 	rcu_read_unlock();
 	ucontext->closing = 0;
+	ucontext->cleanup_retryable = false;
 
 #ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
 	ucontext->umem_tree = RB_ROOT;
diff --git a/sys/ofed/include/rdma/ib_verbs.h b/sys/ofed/include/rdma/ib_verbs.h
index 45a25dc06c45..723db4a659cf 100644
--- a/sys/ofed/include/rdma/ib_verbs.h
+++ b/sys/ofed/include/rdma/ib_verbs.h
@@ -1364,6 +1364,20 @@ struct ib_fmr_attr {
 
 struct ib_umem;
 
+enum rdma_remove_reason {
+	/*
+	 * Userspace requested uobject deletion or initial try
+	 * to remove uobject via cleanup. Call could fail
+	 */
+	RDMA_REMOVE_DESTROY,
+	/* Context deletion. This call should delete the actual object itself */
+	RDMA_REMOVE_CLOSE,
+	/* Driver is being hot-unplugged. This call should delete the actual object itself */
+	RDMA_REMOVE_DRIVER_REMOVE,
+	/* uobj is being cleaned-up before being committed */
+	RDMA_REMOVE_ABORT,
+};
+
 struct ib_ucontext {
 	struct ib_device       *device;
 	struct list_head	pd_list;
@@ -1379,6 +1393,8 @@ struct ib_ucontext {
 	struct list_head	rwq_ind_tbl_list;
 	int			closing;
 
+	bool cleanup_retryable;
+
 	pid_t			tgid;
 #ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
 	struct rb_root      umem_tree;
@@ -2213,6 +2229,46 @@ static inline bool ib_is_udata_cleared(struct ib_udata *udata,
 	return ret;
 }
 
+/**
+ * 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