From 82eb481da64586ccd287b2b2c5a086202c65e7eb Mon Sep 17 00:00:00 2001 From: Weihang Li Date: Fri, 21 May 2021 17:29:54 +0800 Subject: [PATCH] RDMA/hns: Use refcount_t APIs for HEM refcount_t is better than integer for reference counting, it will WARN on overflow/underflow and avoid use-after-free risks. Link: https://lore.kernel.org/r/1621589395-2435-5-git-send-email-liweihang@huawei.com Signed-off-by: Weihang Li Signed-off-by: Jason Gunthorpe --- drivers/infiniband/hw/hns/hns_roce_hem.c | 32 +++++++++++++++----------------- drivers/infiniband/hw/hns/hns_roce_hem.h | 4 ++-- 2 files changed, 17 insertions(+), 19 deletions(-) diff --git a/drivers/infiniband/hw/hns/hns_roce_hem.c b/drivers/infiniband/hw/hns/hns_roce_hem.c index 63776da..fe6940b 100644 --- a/drivers/infiniband/hw/hns/hns_roce_hem.c +++ b/drivers/infiniband/hw/hns/hns_roce_hem.c @@ -271,7 +271,6 @@ static struct hns_roce_hem *hns_roce_alloc_hem(struct hns_roce_dev *hr_dev, if (!hem) return NULL; - hem->refcount = 0; INIT_LIST_HEAD(&hem->chunk_list); order = get_order(hem_alloc_size); @@ -618,7 +617,7 @@ static int hns_roce_table_mhop_get(struct hns_roce_dev *hr_dev, mutex_lock(&table->mutex); if (table->hem[index.buf]) { - ++table->hem[index.buf]->refcount; + refcount_inc(&table->hem[index.buf]->refcount); goto out; } @@ -637,7 +636,7 @@ static int hns_roce_table_mhop_get(struct hns_roce_dev *hr_dev, } } - ++table->hem[index.buf]->refcount; + refcount_set(&table->hem[index.buf]->refcount, 1); goto out; err_alloc: @@ -663,7 +662,7 @@ int hns_roce_table_get(struct hns_roce_dev *hr_dev, mutex_lock(&table->mutex); if (table->hem[i]) { - ++table->hem[i]->refcount; + refcount_inc(&table->hem[i]->refcount); goto out; } @@ -686,7 +685,7 @@ int hns_roce_table_get(struct hns_roce_dev *hr_dev, goto out; } - ++table->hem[i]->refcount; + refcount_set(&table->hem[i]->refcount, 1); out: mutex_unlock(&table->mutex); return ret; @@ -753,11 +752,11 @@ static void hns_roce_table_mhop_put(struct hns_roce_dev *hr_dev, return; } - mutex_lock(&table->mutex); - if (check_refcount && (--table->hem[index.buf]->refcount > 0)) { - mutex_unlock(&table->mutex); + if (!check_refcount) + mutex_lock(&table->mutex); + else if (!refcount_dec_and_mutex_lock(&table->hem[index.buf]->refcount, + &table->mutex)) return; - } clear_mhop_hem(hr_dev, table, obj, &mhop, &index); free_mhop_hem(hr_dev, table, &mhop, &index); @@ -779,16 +778,15 @@ void hns_roce_table_put(struct hns_roce_dev *hr_dev, i = (obj & (table->num_obj - 1)) / (table->table_chunk_size / table->obj_size); - mutex_lock(&table->mutex); + if (!refcount_dec_and_mutex_lock(&table->hem[i]->refcount, + &table->mutex)) + return; - if (--table->hem[i]->refcount == 0) { - /* Clear HEM base address */ - if (hr_dev->hw->clear_hem(hr_dev, table, obj, 0)) - dev_warn(dev, "Clear HEM base address failed.\n"); + if (hr_dev->hw->clear_hem(hr_dev, table, obj, 0)) + dev_warn(dev, "failed to clear HEM base address.\n"); - hns_roce_free_hem(hr_dev, table->hem[i]); - table->hem[i] = NULL; - } + hns_roce_free_hem(hr_dev, table->hem[i]); + table->hem[i] = NULL; mutex_unlock(&table->mutex); } diff --git a/drivers/infiniband/hw/hns/hns_roce_hem.h b/drivers/infiniband/hw/hns/hns_roce_hem.h index 13fdeb3..ffa65e8 100644 --- a/drivers/infiniband/hw/hns/hns_roce_hem.h +++ b/drivers/infiniband/hw/hns/hns_roce_hem.h @@ -88,8 +88,8 @@ struct hns_roce_hem_chunk { }; struct hns_roce_hem { - struct list_head chunk_list; - int refcount; + struct list_head chunk_list; + refcount_t refcount; }; struct hns_roce_hem_iter { -- 2.7.4