[PATCH 3/3] nvme: only setup block integrity if supported by the driver

[Christoph Hellwig]

Any chance to get a review for this one?  Without it we'll reliably
crash the kernel if a fabrics target advertises metadata support.

On Sat, May 20, 2017 at 03:14:45PM +0200, Christoph Hellwig wrote:
> Currently only the PCIe driver supports metadata, so we should not claim
> integrity support for the other drivers.  This prevents nasty crashes
> with targets that advertise metadata support on fabrics.
> 
> Also use the opportunity to factor out some code into a separate helper
> that isn't even compiled if CONFIG_BLK_DEV_INTEGRITY is disabled.
> 
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> ---
>  drivers/nvme/host/core.c | 50 ++++++++++++++++++++++++++++++------------------
>  drivers/nvme/host/nvme.h |  1 +
>  drivers/nvme/host/pci.c  |  1 +
>  3 files changed, 33 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 79b78bd67b07..f6dd4fed56a4 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -925,6 +925,29 @@ static int nvme_getgeo(struct block_device *bdev, struct hd_geometry *geo)
>  }
>  
>  #ifdef CONFIG_BLK_DEV_INTEGRITY
> +static void nvme_prep_integrity(struct gendisk *disk, struct nvme_id_ns *id,
> +		u16 bs)
> +{
> +	struct nvme_ns *ns = disk->private_data;
> +	u16 old_ms = ns->ms;
> +	u8 pi_type = 0;
> +
> +	ns->ms = le16_to_cpu(id->lbaf[id->flbas & NVME_NS_FLBAS_LBA_MASK].ms);
> +	ns->ext = ns->ms && (id->flbas & NVME_NS_FLBAS_META_EXT);
> +
> +	/* PI implementation requires metadata equal t10 pi tuple size */
> +	if (ns->ms == sizeof(struct t10_pi_tuple))
> +		pi_type = id->dps & NVME_NS_DPS_PI_MASK;
> +
> +	if (blk_get_integrity(disk) &&
> +	    (ns->pi_type != pi_type || ns->ms != old_ms ||
> +	     bs != queue_logical_block_size(disk->queue) ||
> +	     (ns->ms && ns->ext)))
> +		blk_integrity_unregister(disk);
> +
> +	ns->pi_type = pi_type;
> +}
> +
>  static void nvme_init_integrity(struct nvme_ns *ns)
>  {
>  	struct blk_integrity integrity;
> @@ -951,6 +974,10 @@ static void nvme_init_integrity(struct nvme_ns *ns)
>  	blk_queue_max_integrity_segments(ns->queue, 1);
>  }
>  #else
> +static void nvme_prep_integrity(struct gendisk *disk, struct nvme_id_ns *id,
> +		u16 bs)
> +{
> +}
>  static void nvme_init_integrity(struct nvme_ns *ns)
>  {
>  }
> @@ -997,37 +1024,22 @@ static int nvme_revalidate_ns(struct nvme_ns *ns, struct nvme_id_ns **id)
>  static void __nvme_revalidate_disk(struct gendisk *disk, struct nvme_id_ns *id)
>  {
>  	struct nvme_ns *ns = disk->private_data;
> -	u8 lbaf, pi_type;
> -	u16 old_ms;
> -	unsigned short bs;
> -
> -	old_ms = ns->ms;
> -	lbaf = id->flbas & NVME_NS_FLBAS_LBA_MASK;
> -	ns->lba_shift = id->lbaf[lbaf].ds;
> -	ns->ms = le16_to_cpu(id->lbaf[lbaf].ms);
> -	ns->ext = ns->ms && (id->flbas & NVME_NS_FLBAS_META_EXT);
> +	u16 bs;
>  
>  	/*
>  	 * If identify namespace failed, use default 512 byte block size so
>  	 * block layer can use before failing read/write for 0 capacity.
>  	 */
> +	ns->lba_shift = id->lbaf[id->flbas & NVME_NS_FLBAS_LBA_MASK].ds;
>  	if (ns->lba_shift == 0)
>  		ns->lba_shift = 9;
>  	bs = 1 << ns->lba_shift;
> -	/* XXX: PI implementation requires metadata equal t10 pi tuple size */
> -	pi_type = ns->ms == sizeof(struct t10_pi_tuple) ?
> -					id->dps & NVME_NS_DPS_PI_MASK : 0;
>  
>  	blk_mq_freeze_queue(disk->queue);
> -	if (blk_get_integrity(disk) && (ns->pi_type != pi_type ||
> -				ns->ms != old_ms ||
> -				bs != queue_logical_block_size(disk->queue) ||
> -				(ns->ms && ns->ext)))
> -		blk_integrity_unregister(disk);
>  
> -	ns->pi_type = pi_type;
> +	if (ns->ctrl->ops->flags & NVME_F_METADATA_SUPPORTED)
> +		nvme_prep_integrity(disk, id, bs);
>  	blk_queue_logical_block_size(ns->queue, bs);
> -
>  	if (ns->ms && !blk_get_integrity(disk) && !ns->ext)
>  		nvme_init_integrity(ns);
>  	if (ns->ms && !(ns->ms == 8 && ns->pi_type) && !blk_get_integrity(disk))
> diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
> index 7c4b0f6636c5..9d6a070d4391 100644
> --- a/drivers/nvme/host/nvme.h
> +++ b/drivers/nvme/host/nvme.h
> @@ -210,6 +210,7 @@ struct nvme_ctrl_ops {
>  	struct module *module;
>  	unsigned int flags;
>  #define NVME_F_FABRICS			(1 << 0)
> +#define NVME_F_METADATA_SUPPORTED	(1 << 1)
>  	int (*reg_read32)(struct nvme_ctrl *ctrl, u32 off, u32 *val);
>  	int (*reg_write32)(struct nvme_ctrl *ctrl, u32 off, u32 val);
>  	int (*reg_read64)(struct nvme_ctrl *ctrl, u32 off, u64 *val);
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index a150b2dd7851..283efc2e8921 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -2041,6 +2041,7 @@ static int nvme_pci_reset_ctrl(struct nvme_ctrl *ctrl)
>  static const struct nvme_ctrl_ops nvme_pci_ctrl_ops = {
>  	.name			= "pcie",
>  	.module			= THIS_MODULE,
> +	.flags			= NVME_F_METADATA_SUPPORTED,
>  	.reg_read32		= nvme_pci_reg_read32,
>  	.reg_write32		= nvme_pci_reg_write32,
>  	.reg_read64		= nvme_pci_reg_read64,
> -- 
> 2.11.0
> 
> 
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