git: ee9aeb312c4c - stable/13 - ibcore: Implement ib_uverbs_get_ucontext_file().

[Hans Petter Selasky]

The branch stable/13 has been updated by hselasky:

URL: https://cgit.FreeBSD.org/src/commit/?id=ee9aeb312c4c5fd58e4ae15567c87d9b04990f89

commit ee9aeb312c4c5fd58e4ae15567c87d9b04990f89
Author:     Hans Petter Selasky <hselasky at FreeBSD.org>
AuthorDate: 2021-06-16 13:01:51 +0000
Commit:     Hans Petter Selasky <hselasky at FreeBSD.org>
CommitDate: 2021-07-26 16:04:31 +0000

    ibcore: Implement ib_uverbs_get_ucontext_file().
    
    Expose ib_ucontext from a given ib_uverbs_file. Drivers that use the ioctl(9)
    API may have the ib_uverbs_file and need a way to get the related ib_ucontext
    from it, this is enabled by this patch.
    
    Downstream patches from this series will use it.
    
    Linux commit:
    7dc08dcfc8c86cb4457e383734ff6844ddaff876
    
    Reviewed by:    kib
    Sponsored by:   Mellanox Technologies // NVIDIA Networking
    
    (cherry picked from commit 79b817084ca891e465fe1a868ef1d9f1a3f33a69)
---
 sys/ofed/drivers/infiniband/core/ib_uverbs_main.c | 24 +++++++++++++++++++++++
 sys/ofed/include/rdma/ib_verbs.h                  |  3 +++
 2 files changed, 27 insertions(+)

diff --git a/sys/ofed/drivers/infiniband/core/ib_uverbs_main.c b/sys/ofed/drivers/infiniband/core/ib_uverbs_main.c
index dff566e71f99..38016681b819 100644
--- a/sys/ofed/drivers/infiniband/core/ib_uverbs_main.c
+++ b/sys/ofed/drivers/infiniband/core/ib_uverbs_main.c
@@ -146,6 +146,30 @@ static int (*uverbs_ex_cmd_table[])(struct ib_uverbs_file *file,
 static void ib_uverbs_add_one(struct ib_device *device);
 static void ib_uverbs_remove_one(struct ib_device *device, void *client_data);
 
+/*
+ * Must be called with the ufile->device->disassociate_srcu held, and the lock
+ * must be held until use of the ucontext is finished.
+ */
+struct ib_ucontext *ib_uverbs_get_ucontext_file(struct ib_uverbs_file *ufile)
+{
+	/*
+	 * We do not hold the hw_destroy_rwsem lock for this flow, instead
+	 * srcu is used. It does not matter if someone races this with
+	 * get_context, we get NULL or valid ucontext.
+	 */
+	struct ib_ucontext *ucontext = READ_ONCE(ufile->ucontext);
+
+	if (!srcu_dereference(ufile->device->ib_dev,
+			      &ufile->device->disassociate_srcu))
+		return ERR_PTR(-EIO);
+
+	if (!ucontext)
+		return ERR_PTR(-EINVAL);
+
+	return ucontext;
+}
+EXPORT_SYMBOL(ib_uverbs_get_ucontext_file);
+
 int uverbs_dealloc_mw(struct ib_mw *mw)
 {
 	struct ib_pd *pd = mw->pd;
diff --git a/sys/ofed/include/rdma/ib_verbs.h b/sys/ofed/include/rdma/ib_verbs.h
index 353181a8d790..da17bc9f8250 100644
--- a/sys/ofed/include/rdma/ib_verbs.h
+++ b/sys/ofed/include/rdma/ib_verbs.h
@@ -67,6 +67,7 @@
 
 struct ifla_vf_info;
 struct ifla_vf_stats;
+struct ib_uverbs_file;
 
 extern struct workqueue_struct *ib_wq;
 extern struct workqueue_struct *ib_comp_wq;
@@ -3390,6 +3391,8 @@ void ib_drain_rq(struct ib_qp *qp);
 void ib_drain_sq(struct ib_qp *qp);
 void ib_drain_qp(struct ib_qp *qp);
 
+struct ib_ucontext *ib_uverbs_get_ucontext_file(struct ib_uverbs_file *ufile);
+
 int ib_resolve_eth_dmac(struct ib_device *device,
 			struct ib_ah_attr *ah_attr);
 #endif /* IB_VERBS_H */