On Thu, May 17, 2018 at 04:02:50PM +0800, Wei Hu (Xavier) wrote:
> This patch modified uar allocation algorithm in hns_roce_uar_alloc
> function to avoid bitmap exhaust.
>
> Signed-off-by: Wei Hu (Xavier) <xavier.hu...@huawei.com>
> ---
>  drivers/infiniband/hw/hns/hns_roce_device.h |  1 +
>  drivers/infiniband/hw/hns/hns_roce_pd.c     | 10 ++++++----
>  2 files changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/infiniband/hw/hns/hns_roce_device.h 
> b/drivers/infiniband/hw/hns/hns_roce_device.h
> index 53c2f1b..412297d4 100644
> --- a/drivers/infiniband/hw/hns/hns_roce_device.h
> +++ b/drivers/infiniband/hw/hns/hns_roce_device.h
> @@ -214,6 +214,7 @@ enum {
>  struct hns_roce_uar {
>       u64             pfn;
>       unsigned long   index;
> +     unsigned long   logic_idx;
>  };
>
>  struct hns_roce_ucontext {
> diff --git a/drivers/infiniband/hw/hns/hns_roce_pd.c 
> b/drivers/infiniband/hw/hns/hns_roce_pd.c
> index 4b41e04..b9f2c87 100644
> --- a/drivers/infiniband/hw/hns/hns_roce_pd.c
> +++ b/drivers/infiniband/hw/hns/hns_roce_pd.c
> @@ -107,13 +107,15 @@ int hns_roce_uar_alloc(struct hns_roce_dev *hr_dev, 
> struct hns_roce_uar *uar)
>       int ret = 0;
>
>       /* Using bitmap to manager UAR index */
> -     ret = hns_roce_bitmap_alloc(&hr_dev->uar_table.bitmap, &uar->index);
> +     ret = hns_roce_bitmap_alloc(&hr_dev->uar_table.bitmap, &uar->logic_idx);
>       if (ret == -1)
>               return -ENOMEM;
>
> -     if (uar->index > 0)
> -             uar->index = (uar->index - 1) %
> +     if (uar->logic_idx > 0 && hr_dev->caps.phy_num_uars > 1)
> +             uar->index = (uar->logic_idx - 1) %
>                            (hr_dev->caps.phy_num_uars - 1) + 1;
> +     else
> +             uar->index = 0;
>

Sorry, but maybe I didn't understand this change fully, but logic_idx is
not initialized at all and one of two (needs to check your uar
allocation): the logic_idx is always zero -> index will be zero too,
or logic_idx is random variable -> index will be random too.

What did you want to do?


>       if (!dev_is_pci(hr_dev->dev)) {
>               res = platform_get_resource(hr_dev->pdev, IORESOURCE_MEM, 0);
> @@ -132,7 +134,7 @@ int hns_roce_uar_alloc(struct hns_roce_dev *hr_dev, 
> struct hns_roce_uar *uar)
>
>  void hns_roce_uar_free(struct hns_roce_dev *hr_dev, struct hns_roce_uar *uar)
>  {
> -     hns_roce_bitmap_free(&hr_dev->uar_table.bitmap, uar->index,
> +     hns_roce_bitmap_free(&hr_dev->uar_table.bitmap, uar->logic_idx,
>                            BITMAP_NO_RR);
>  }
>
> --
> 1.9.1
>

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