[PATCH] nvme-pci: another 64-bit division for the host memory buffer code

[Sagi Grimberg]

This looks fine, but is there a good reason why
shouldn't DIV_ROUND_UP take care of that instead of you
open-coding it?

Reviewed-by: Sagi Grimberg <sagi at rimberg.me>

On 13/06/17 18:31, Christoph Hellwig wrote:
> [to be folded into "nvme-pci: implement host memory buffer support"]
> 
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> 
> ---
> 
> Now tested with a full i386 build, sigh..
> ---
>   drivers/nvme/host/pci.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index 788bb2c479d0..4b50fef1fa1b 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -1591,12 +1591,14 @@ static int nvme_alloc_host_mem(struct nvme_dev *dev, u64 min, u64 preferred)
>   	struct nvme_host_mem_buf_desc *descs;
>   	u32 chunk_size, max_entries, i = 0;
>   	void **bufs;
> -	u64 size;
> +	u64 size, tmp;
>   
>   	/* start big and work our way down */
>   	chunk_size = min(preferred, (u64)PAGE_SIZE << MAX_ORDER);
>   retry:
> -	max_entries = DIV_ROUND_UP(preferred, chunk_size);
> +	tmp = (preferred + chunk_size - 1);
> +	do_div(tmp, chunk_size);
> +	max_entries = tmp;
>   	descs = kcalloc(max_entries, sizeof(*descs), GFP_KERNEL);
>   	if (!descs)
>   		goto out;
>