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From: Leon Romanovsky <leon@kernel.org>
To: Lijun Ou <oulijun@huawei.com>
Cc: dledford@redhat.com, jgg@ziepe.ca, linux-rdma@vger.kernel.org,
	linuxarm@huawei.com
Subject: Re: [PATCH for-next 8/9] RDMA/hns: Kernel notify usr space to stop ring db
Date: Mon, 12 Aug 2019 08:52:20 +0300	[thread overview]
Message-ID: <20190812055220.GA8440@mtr-leonro.mtl.com> (raw)
In-Reply-To: <1565343666-73193-9-git-send-email-oulijun@huawei.com>

On Fri, Aug 09, 2019 at 05:41:05PM +0800, Lijun Ou wrote:
> From: Yangyang Li <liyangyang20@huawei.com>
>
> In the reset scenario, if the kernel receives the reset signal,
> it needs to notify the user space to stop ring doorbell.

I doubt about it, it is racy like hell and relies on assumption that
userspace will honor such request to stop.

>
> Signed-off-by: Yangyang Li <liyangyang20@huawei.com>
> ---
>  drivers/infiniband/hw/hns/hns_roce_device.h |  4 +++
>  drivers/infiniband/hw/hns/hns_roce_hw_v2.c  | 52 ++++++++++++++++++++++++++++-
>  drivers/infiniband/hw/hns/hns_roce_hw_v2.h  |  4 +++
>  drivers/infiniband/hw/hns/hns_roce_main.c   | 22 ++++++------
>  4 files changed, 70 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/infiniband/hw/hns/hns_roce_device.h b/drivers/infiniband/hw/hns/hns_roce_device.h
> index 32465f5..be65fce 100644
> --- a/drivers/infiniband/hw/hns/hns_roce_device.h
> +++ b/drivers/infiniband/hw/hns/hns_roce_device.h
> @@ -268,6 +268,8 @@ enum {
>
>  #define PAGE_ADDR_SHIFT				12
>
> +#define HNS_ROCE_IS_RESETTING			1
> +
>  struct hns_roce_uar {
>  	u64		pfn;
>  	unsigned long	index;
> @@ -1043,6 +1045,8 @@ struct hns_roce_dev {
>  	u32			odb_offset;
>  	dma_addr_t		tptr_dma_addr;	/* only for hw v1 */
>  	u32			tptr_size;	/* only for hw v1 */
> +	struct page		*reset_page; /* store reset state */
> +	void			*reset_kaddr; /* addr of reset page */
>  	const struct hns_roce_hw *hw;
>  	void			*priv;
>  	struct workqueue_struct *irq_workq;
> diff --git a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
> index d33341e..138e5a8 100644
> --- a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
> +++ b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
> @@ -1867,17 +1867,49 @@ static void hns_roce_free_link_table(struct hns_roce_dev *hr_dev,
>  			  link_tbl->table.map);
>  }
>
> +static int hns_roce_v2_get_reset_page(struct hns_roce_dev *hr_dev)
> +{
> +	hr_dev->reset_page = alloc_page(GFP_KERNEL | __GFP_ZERO);
> +	if (!hr_dev->reset_page)
> +		return -ENOMEM;
> +
> +	hr_dev->reset_kaddr = vmap(&hr_dev->reset_page, 1, VM_MAP, PAGE_KERNEL);
> +	if (!hr_dev->reset_kaddr)
> +		goto err_with_vmap;
> +
> +	return 0;
> +
> +err_with_vmap:
> +	put_page(hr_dev->reset_page);

Are you sure that pages allocated with alloc_page() are released with put_page()?

I would say with high confidence that whole this patch is wrong.

Thanks

  reply	other threads:[~2019-08-12  5:52 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-09  9:40 [PATCH for-next 0/9] Bugfixes for 5.3-rc2 Lijun Ou
2019-08-09  9:40 ` [PATCH for-next 1/9] RDMA/hns: Logic optimization of wc_flags Lijun Ou
2019-08-09  9:40 ` [PATCH for-next 2/9] RDMA/hns: Bugfix for creating qp attached to srq Lijun Ou
2019-08-12 15:29   ` Doug Ledford
2019-08-09  9:41 ` [PATCH for-next 3/9] RDMA/hns: Completely release qp resources when hw err Lijun Ou
2019-08-12 15:29   ` Doug Ledford
2019-08-14  6:02     ` Yangyang Li
2019-08-14 15:05       ` Doug Ledford
2019-08-14 18:47         ` Leon Romanovsky
2019-08-19 17:39           ` Doug Ledford
2019-10-08  8:43             ` liweihang
2019-08-09  9:41 ` [PATCH for-next 4/9] RDMA/hns: Modify pi vlaue when cq overflows Lijun Ou
2019-08-09  9:41 ` [PATCH for-next 5/9] RDMA/hns: Bugfix for slab-out-of-bounds when unloading hip08 driver Lijun Ou
2019-08-09  9:41 ` [PATCH for-next 6/9] RDMA/hns: bugfix for slab-out-of-bounds when loading " Lijun Ou
2019-08-09  9:41 ` [PATCH for-next 7/9] RDMA/hns: Remove unuseful member Lijun Ou
2019-08-09  9:41 ` [PATCH for-next 8/9] RDMA/hns: Kernel notify usr space to stop ring db Lijun Ou
2019-08-12  5:52   ` Leon Romanovsky [this message]
2019-08-12 13:14     ` Jason Gunthorpe
2019-08-14  5:54       ` Yangyang Li
2019-08-09  9:41 ` [PATCH for-next 9/9] RDMA/hns: Copy some information of AV to user Lijun Ou
2019-10-21 17:23   ` Doug Ledford
2019-10-22  1:13     ` oulijun
2019-08-13 16:34 ` [PATCH for-next 0/9] Bugfixes for 5.3-rc2 Doug Ledford
2019-08-24  6:23   ` oulijun

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