linux-kernel - Re: [PATCH 1/3] lightnvm: use internal allocation for chunk log page

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Date:   Fri, 7 Sep 2018 12:38:30 +0200
From:   Matias Bjørling <mb@...htnvm.io>
To:     javier@...igon.com
Cc:     igor.j.konopko@...el.com, marcin.dziegielewski@...el.com,
        linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
        javier@...xlabs.com
Subject: Re: [PATCH 1/3] lightnvm: use internal allocation for chunk log page

On 08/29/2018 12:09 PM, Javier González wrote:
> The lightnvm subsystem provides helpers to retrieve chunk metadata,
> where the target needs to provide a buffer to store the metadata. An
> implicit assumption is that this buffer is contiguous and can be used to
> retrieve the data from the device. If the device exposes too many
> chunks, then kmalloc might fail, thus failing instance creation.
> 
> This patch removes this assumption by implementing an internal buffer in
> the lightnvm subsystem to retrieve chunk metadata. Targets can then
> use virtual memory allocations. Since this is a target API change, adapt
> pblk accordingly.
> 
> Signed-off-by: Javier González <javier@...xlabs.com>
> ---
>   drivers/lightnvm/pblk-core.c |  4 ++--
>   drivers/lightnvm/pblk-init.c |  2 +-
>   drivers/nvme/host/lightnvm.c | 23 +++++++++++++++--------
>   3 files changed, 18 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
> index fdcbeb920c9e..a311cc29afd8 100644
> --- a/drivers/lightnvm/pblk-core.c
> +++ b/drivers/lightnvm/pblk-core.c
> @@ -120,7 +120,7 @@ static void pblk_end_io_erase(struct nvm_rq *rqd)
>   /*
>    * Get information for all chunks from the device.
>    *
> - * The caller is responsible for freeing the returned structure
> + * The caller is responsible for freeing (vmalloc) the returned structure
>    */
>   struct nvm_chk_meta *pblk_get_chunk_meta(struct pblk *pblk)
>   {
> @@ -134,7 +134,7 @@ struct nvm_chk_meta *pblk_get_chunk_meta(struct pblk *pblk)
>   	ppa.ppa = 0;
>   
>   	len = geo->all_chunks * sizeof(*meta);
> -	meta = kzalloc(len, GFP_KERNEL);
> +	meta = vzalloc(len);
>   	if (!meta)
>   		return ERR_PTR(-ENOMEM);
>   
> diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
> index e0db6de137d6..a99854439224 100644
> --- a/drivers/lightnvm/pblk-init.c
> +++ b/drivers/lightnvm/pblk-init.c
> @@ -983,7 +983,7 @@ static int pblk_lines_init(struct pblk *pblk)
>   
>   	pblk_set_provision(pblk, nr_free_chks);
>   
> -	kfree(chunk_meta);
> +	vfree(chunk_meta);
>   	return 0;
>   
>   fail_free_lines:
> diff --git a/drivers/nvme/host/lightnvm.c b/drivers/nvme/host/lightnvm.c
> index 2c96e7fcdcac..5bfa354c5dd5 100644
> --- a/drivers/nvme/host/lightnvm.c
> +++ b/drivers/nvme/host/lightnvm.c
> @@ -579,7 +579,7 @@ static int nvme_nvm_get_chk_meta(struct nvm_dev *ndev,
>   	struct nvm_geo *geo = &ndev->geo;
>   	struct nvme_ns *ns = ndev->q->queuedata;
>   	struct nvme_ctrl *ctrl = ns->ctrl;
> -	struct nvme_nvm_chk_meta *dev_meta = (struct nvme_nvm_chk_meta *)meta;
> +	struct nvme_nvm_chk_meta *dev_meta, *dev_meta_off;
>   	struct ppa_addr ppa;
>   	size_t left = nchks * sizeof(struct nvme_nvm_chk_meta);
>   	size_t log_pos, offset, len;
> @@ -591,6 +591,10 @@ static int nvme_nvm_get_chk_meta(struct nvm_dev *ndev,
>   	 */
>   	max_len = min_t(unsigned int, ctrl->max_hw_sectors << 9, 256 * 1024);
>   
> +	dev_meta = kmalloc(max_len, GFP_KERNEL);
> +	if (!dev_meta)
> +		return -ENOMEM;
> +
>   	/* Normalize lba address space to obtain log offset */
>   	ppa.ppa = slba;
>   	ppa = dev_to_generic_addr(ndev, ppa);
> @@ -604,6 +608,9 @@ static int nvme_nvm_get_chk_meta(struct nvm_dev *ndev,
>   	while (left) {
>   		len = min_t(unsigned int, left, max_len);
>   
> +		memset(dev_meta, 0, max_len);
> +		dev_meta_off = dev_meta;
> +
>   		ret = nvme_get_log_ext(ctrl, ns, NVME_NVM_LOG_REPORT_CHUNK,
>   				dev_meta, len, offset);
>   		if (ret) {
> @@ -612,15 +619,15 @@ static int nvme_nvm_get_chk_meta(struct nvm_dev *ndev,
>   		}
>   
>   		for (i = 0; i < len; i += sizeof(struct nvme_nvm_chk_meta)) {
> -			meta->state = dev_meta->state;
> -			meta->type = dev_meta->type;
> -			meta->wi = dev_meta->wi;
> -			meta->slba = le64_to_cpu(dev_meta->slba);
> -			meta->cnlb = le64_to_cpu(dev_meta->cnlb);
> -			meta->wp = le64_to_cpu(dev_meta->wp);
> +			meta->state = dev_meta_off->state;
> +			meta->type = dev_meta_off->type;
> +			meta->wi = dev_meta_off->wi;
> +			meta->slba = le64_to_cpu(dev_meta_off->slba);
> +			meta->cnlb = le64_to_cpu(dev_meta_off->cnlb);
> +			meta->wp = le64_to_cpu(dev_meta_off->wp);
>   
>   			meta++;
> -			dev_meta++;
> +			dev_meta_off++;
>   		}
>   
>   		offset += len;
> 

Thanks. Applied for 4.20.