Re: [PATCH v3 1/2] scsi: leapraid: balance host references for firmware log VMAs

[Hao Dongdong <doubled@leap-io-kernel.com>]

在 2026/8/14 11:38, Linmao Li 写道:
> leapraid_fw_mmap() keeps the Scsi_Host reference obtained while
> looking up the adapter for the lifetime of the initial VMA.  The VMA
> close callback drops that reference.
> 
> The open callback is also invoked when a VMA is duplicated or split,
> but it only increments mmap_refcnt.  Since every corresponding close
> callback drops a host reference, cloning the mapping can release the
> host while another VMA still refers to the adapter.
> 
> Take a host device reference for every VMA open and release the lookup
> reference once the initial mapping has acquired its own reference.  Use
> get_device() because a VMA can be cloned after the host enters SHOST_DEL;
> an existing VMA still pins the host at that point and open cannot fail.
> 
> Fixes: 5597088c9e79 ("scsi: leapraid: Add new SCSI driver")
> Signed-off-by: Linmao Li <lilinmao@kylinos.cn>
> ---
>  drivers/scsi/leapraid/leapraid_app.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/leapraid/leapraid_app.c b/drivers/scsi/leapraid/leapraid_app.c
> index 742f19c07fcbb..841027ce2501c 100644
> --- a/drivers/scsi/leapraid/leapraid_app.c
> +++ b/drivers/scsi/leapraid/leapraid_app.c
> @@ -697,6 +697,7 @@ static void leapraid_fw_mmap_open(struct vm_area_struct *vma)
>  	if (!adapter)
>  		return;
>  
> +	get_device(&adapter->shost->shost_gendev);
>  	atomic_inc(&adapter->fw_log_desc.mmap_refcnt);
>  }
>  
> @@ -767,7 +768,6 @@ static int leapraid_fw_mmap(struct file *filp, struct vm_area_struct *vma)
>  	vma->vm_private_data = adapter;
>  	vma->vm_ops = &leapraid_fw_mmap_vm_ops;
>  	leapraid_fw_mmap_open(vma);
> -	adapter = NULL;
>  
>  	rc = 0;
>  out_put:

Thanks for the fix. This correctly fixes the issue.

Reviewed-by: Dongdong Hao <doubled@leap-io-kernel.com>