From 73607410f4f1b0d5c3d0af2d70a79c265482a0e3 Mon Sep 17 00:00:00 2001 From: Sriharsha Basavapatna Date: Tue, 19 May 2026 20:30:38 +0530 Subject: [PATCH] RDMA/bnxt_re: Enhance dbr usecnt logic in doorbell uapis The current logic in the doorbell cleanup function is not sufficient for a change in a subsequent patch, that fails doorbell remove operation in some conditions. The cleanup should facilitate freeing of the dbr object when the caller may not retry the teardown operation (implicit teardown: process-exit/driver-removal). Extend this counter to use kref mechanism so that the dbr object gets freed (via kref callback) when there are no more references to it, rather than directly freeing it in the cleanup uapi. Link: https://patch.msgid.link/r/20260519150041.7251-7-sriharsha.basavapatna@broadcom.com Signed-off-by: Sriharsha Basavapatna Reviewed-by: Selvin Xavier Signed-off-by: Jason Gunthorpe --- drivers/infiniband/hw/bnxt_re/ib_verbs.h | 3 ++- drivers/infiniband/hw/bnxt_re/uapi.c | 16 +++++++++++++--- 2 files changed, 15 insertions(+), 4 deletions(-) diff --git a/drivers/infiniband/hw/bnxt_re/ib_verbs.h b/drivers/infiniband/hw/bnxt_re/ib_verbs.h index 08f71a94d55d..13dac48ed453 100644 --- a/drivers/infiniband/hw/bnxt_re/ib_verbs.h +++ b/drivers/infiniband/hw/bnxt_re/ib_verbs.h @@ -167,7 +167,7 @@ struct bnxt_re_dbr_obj { struct bnxt_re_dev *rdev; struct bnxt_qplib_dpi dpi; struct bnxt_re_user_mmap_entry *entry; - atomic_t usecnt; /* QPs using this dbr */ + struct kref usecnt; /* 1 (uobject) + n (QPs using this dbr) */ }; struct bnxt_re_flow { @@ -308,4 +308,5 @@ void bnxt_re_unlock_cqs(struct bnxt_re_qp *qp, unsigned long flags); struct bnxt_re_user_mmap_entry* bnxt_re_mmap_entry_insert(struct bnxt_re_ucontext *uctx, u64 mem_offset, enum bnxt_re_mmap_flag mmap_flag, u64 *offset); +void bnxt_re_dbr_kref_release(struct kref *ref); #endif /* __BNXT_RE_IB_VERBS_H__ */ diff --git a/drivers/infiniband/hw/bnxt_re/uapi.c b/drivers/infiniband/hw/bnxt_re/uapi.c index 3eaee7101615..b8fc8bfba2ad 100644 --- a/drivers/infiniband/hw/bnxt_re/uapi.c +++ b/drivers/infiniband/hw/bnxt_re/uapi.c @@ -369,6 +369,7 @@ static int UVERBS_HANDLER(BNXT_RE_METHOD_DBR_ALLOC)(struct uverbs_attr_bundle *a } obj->rdev = rdev; + kref_init(&obj->usecnt); uobj->object = obj; uverbs_finalize_uobj_create(attrs, BNXT_RE_ALLOC_DBR_HANDLE); @@ -391,15 +392,24 @@ static int UVERBS_HANDLER(BNXT_RE_METHOD_DBR_ALLOC)(struct uverbs_attr_bundle *a return ret; } +void bnxt_re_dbr_kref_release(struct kref *ref) +{ + struct bnxt_re_dbr_obj *obj = + container_of(ref, struct bnxt_re_dbr_obj, usecnt); + struct bnxt_re_dev *rdev = obj->rdev; + + rdma_user_mmap_entry_remove(&obj->entry->rdma_entry); + bnxt_qplib_free_uc_dpi(&rdev->qplib_res, &obj->dpi); + kfree(obj); +} + static int bnxt_re_dbr_cleanup(struct ib_uobject *uobject, enum rdma_remove_reason why, struct uverbs_attr_bundle *attrs) { struct bnxt_re_dbr_obj *obj = uobject->object; - struct bnxt_re_dev *rdev = obj->rdev; - rdma_user_mmap_entry_remove(&obj->entry->rdma_entry); - bnxt_qplib_free_uc_dpi(&rdev->qplib_res, &obj->dpi); + kref_put(&obj->usecnt, bnxt_re_dbr_kref_release); return 0; }