Re: [Qemu-devel] [PATCH 0/4] RFC: A VFIO based block driver for NVMe device

[Fam Zheng <famz@redhat.com>]

On Tue, 12/20 15:04, no-reply@patchew.org wrote:
> ERROR: that open brace { should be on the previous line
> #287: FILE: util/vfio-helpers.c:214:
> +    struct vfio_group_status group_status =
> +    { .argsz = sizeof(group_status) };

Hmm, it may indeed look better.

> ERROR: Use of volatile is usually wrong: see Documentation/volatile-considered-harmful.txt
> #145: FILE: block/nvme.c:92:
> +    volatile uint32_t *doorbell;
> 
> ERROR: Use of volatile is usually wrong: see Documentation/volatile-considered-harmful.txt
> #169: FILE: block/nvme.c:116:
> +typedef volatile struct {

These are shared with hardware, even volatile-considered-harmful.txt admits it
can be valid:

> - Pointers to data structures in coherent memory which might be modified
>   by I/O devices can, sometimes, legitimately be volatile.  A ring buffer
>   used by a network adapter, where that adapter changes pointers to
>   indicate which descriptors have been processed, is an example of this
>   type of situation.

Fam