[AMD Official Use Only - General]
> -----Original Message-----
> From: Chai, Thomas <YiPeng.Chai@xxxxxxx>
> Sent: Wednesday, April 3, 2024 3:07 PM
> To: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
> Cc: Chai, Thomas <YiPeng.Chai@xxxxxxx>; Zhang, Hawking
> <Hawking.Zhang@xxxxxxx>; Zhou1, Tao <Tao.Zhou1@xxxxxxx>; Li, Candice
> <Candice.Li@xxxxxxx>; Wang, Yang(Kevin) <KevinYang.Wang@xxxxxxx>; Yang,
> Stanley <Stanley.Yang@xxxxxxx>; Chai, Thomas <YiPeng.Chai@xxxxxxx>
> Subject: [PATCH] drm/amdgpu: Fix incorrect return value
>
> [Why]
> After calling amdgpu_vram_mgr_reserve_range multiple times with the same
> address, calling amdgpu_vram_mgr_query_page_status will always return -
> EBUSY.
> From the second call to amdgpu_vram_mgr_reserve_range, the same address
> will be added to the reservations_pending list again and is never moved to the
> reserved_pages list because the address had been reserved.
>
> [How]
> First add the address status check before calling
> amdgpu_vram_mgr_do_reserve, if the address is already reserved, do nothing; If
> the address is already in the reservations_pending list, directly reserve memory;
> only add new nodes for the addresses that are not in the reserved_pages list and
> reservations_pending list.
>
> Signed-off-by: YiPeng Chai <YiPeng.Chai@xxxxxxx>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 28 +++++++++++++-------
> 1 file changed, 19 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> index 1e36c428d254..0bf3f4092900 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> @@ -317,7 +317,6 @@ static void amdgpu_vram_mgr_do_reserve(struct
> ttm_resource_manager *man)
>
> dev_dbg(adev->dev, "Reservation 0x%llx - %lld, Succeeded\n",
> rsv->start, rsv->size);
> -
> vis_usage = amdgpu_vram_mgr_vis_size(adev, block);
> atomic64_add(vis_usage, &mgr->vis_usage);
> spin_lock(&man->bdev->lru_lock);
> @@ -340,19 +339,30 @@ int amdgpu_vram_mgr_reserve_range(struct
> amdgpu_vram_mgr *mgr,
> uint64_t start, uint64_t size)
> {
> struct amdgpu_vram_reservation *rsv;
> + int ret = 0;
>
> - rsv = kzalloc(sizeof(*rsv), GFP_KERNEL);
> - if (!rsv)
> - return -ENOMEM;
> + ret = amdgpu_vram_mgr_query_page_status(mgr, start);
> + if (!ret)
> + return 0;
> +
> + if (ret == -ENOENT) {
> + rsv = kzalloc(sizeof(*rsv), GFP_KERNEL);
> + if (!rsv)
> + return -ENOMEM;
>
> - INIT_LIST_HEAD(&rsv->allocated);
> - INIT_LIST_HEAD(&rsv->blocks);
> + INIT_LIST_HEAD(&rsv->allocated);
> + INIT_LIST_HEAD(&rsv->blocks);
>
> - rsv->start = start;
> - rsv->size = size;
> + rsv->start = start;
> + rsv->size = size;
> +
> + mutex_lock(&mgr->lock);
> + list_add_tail(&rsv->blocks, &mgr->reservations_pending);
> + mutex_unlock(&mgr->lock);
[Tao] we can drop the mutex_unlock and add if (ret != -ENOENT) for the second mutex_lock to avoid unlocking/locking repeatedly.
> +
> + }
>
> mutex_lock(&mgr->lock);
> - list_add_tail(&rsv->blocks, &mgr->reservations_pending);
> amdgpu_vram_mgr_do_reserve(&mgr->manager);
> mutex_unlock(&mgr->lock);
>
> --
> 2.34.1
