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SubjectRe: [PATCH v2] nvme: fix multipath crash when ANA desactivated
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On 7/10/2019 12:29 AM, Christoph Hellwig wrote:
> On Sat, Jul 06, 2019 at 01:06:44PM +0300, Max Gurtovoy wrote:
>>> + /* check if multipath is enabled and we have the capability */
>>> + if (!multipath)
>>> + return 0;
>>> + if (!ctrl->subsys || ((ctrl->subsys->cmic & (1 << 3)) != 0))
>> shouldn't it be:
>>
>> if (!ctrl->subsys || ((ctrl->subsys->cmic & (1 << 3)) == 0))
>>
>> or
>>
>> if (!ctrl->subsys || !(ctrl->subsys->cmic & (1 << 3)))
>>
>>
>> Otherwise, you don't really do any initialization and return 0 in case you have the capability, right ?
> Yes. FYI, my idea how to fix this would be something like:
>
> diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
> index a9a927677970..cdb3e5baa329 100644
> --- a/drivers/nvme/host/multipath.c
> +++ b/drivers/nvme/host/multipath.c
> @@ -12,11 +12,6 @@ module_param(multipath, bool, 0444);
> MODULE_PARM_DESC(multipath,
> "turn on native support for multiple controllers per subsystem");
>
> -inline bool nvme_ctrl_use_ana(struct nvme_ctrl *ctrl)
> -{
> - return multipath && ctrl->subsys && (ctrl->subsys->cmic & (1 << 3));
> -}
> -
> /*
> * If multipathing is enabled we need to always use the subsystem instance
> * number for numbering our devices to avoid conflicts between subsystems that
> @@ -622,7 +617,7 @@ int nvme_mpath_init(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
> {
> int error;
>
> - if (!nvme_ctrl_use_ana(ctrl))
> + if (!multipath || !ctrl->subsys || !(ctrl->subsys->cmic & (1 << 3)))
> return 0;
>
> ctrl->anacap = id->anacap;
> diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
> index 716a876119c8..14eca76bec5c 100644
> --- a/drivers/nvme/host/nvme.h
> +++ b/drivers/nvme/host/nvme.h
> @@ -485,7 +485,10 @@ extern const struct attribute_group *nvme_ns_id_attr_groups[];
> extern const struct block_device_operations nvme_ns_head_ops;
>
> #ifdef CONFIG_NVME_MULTIPATH
> -bool nvme_ctrl_use_ana(struct nvme_ctrl *ctrl);
> +static inline bool nvme_ctrl_use_ana(struct nvme_ctrl *ctrl)
> +{
> + return ctrl->ana_log_buf != NULL;
> +}
> void nvme_set_disk_name(char *disk_name, struct nvme_ns *ns,
> struct nvme_ctrl *ctrl, int *flags);
> void nvme_failover_req(struct request *req);

Yes this looks good.

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