Message-ID: <548051BE.3000602@amd.com>
Date: Thu, 4 Dec 2014 14:21:18 +0200
From: Oded Gabbay <oded.gabbay@amd.com>
Organization: AMD
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0
MIME-Version: 1.0
To: Sasha Levin <sasha.levin@oracle.com>
CC: <airlied@linux.ie>, <alexander.deucher@amd.com>, <j.glisse@gmail.com>,
        <linux-kernel@vger.kernel.org>, <dri-devel@lists.freedesktop.org>,
        <John.Bridgman@amd.com>, <Andrew.Lewycky@amd.com>, <joro@8bytes.org>
Subject: Re: [PATCH] amdkfd: use sizeof(long) granularity for the pasid bitmask
References: <1417616785-5143-1-git-send-email-sasha.levin@oracle.com>
In-Reply-To: <1417616785-5143-1-git-send-email-sasha.levin@oracle.com>
Content-Type: text/plain; charset="utf-8"; format=flowed
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org


On 12/03/2014 04:26 PM, Sasha Levin wrote:
> All the bit operations (such as find_first_zero_bit()) read sizeof(long) bytes
> at a time. If we allocated less than sizeof(long) bytes for the bitmask we
> would be accessing invalid memory when working with the bitmask.
>
> Change the allocator to allocate sizeof(long) multiples for the bitmask.
>
> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
> ---
>   drivers/gpu/drm/amd/amdkfd/kfd_pasid.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_pasid.c b/drivers/gpu/drm/amd/amdkfd/kfd_pasid.c
> index 2458ab7..71699ad 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_pasid.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_pasid.c
> @@ -32,8 +32,7 @@ int kfd_pasid_init(void)
>   {
>   	pasid_limit = max_num_of_processes;
>
> -	pasid_bitmap = kzalloc(DIV_ROUND_UP(pasid_limit, BITS_PER_BYTE),
> -				GFP_KERNEL);
> +	pasid_bitmap = kzalloc(BITS_TO_LONGS(pasid_limit), GFP_KERNEL);
>   	if (!pasid_bitmap)
>   		return -ENOMEM;
>
>

Thanks!
Applied to my -next tree.

Oded
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/