# Re: \[PATCH 15/18\] scsi: allocate scsi\_cmnd structures as part of struct request

- From: Bart Van Assche \<hidden\>
- Date: 2017-01-27 18:39:46 
- List: linux-block
- Page: https://ratatoskr.run/linux-block/2017/01/6370255
- Thread: https://ratatoskr.run/linux-scsi/2017/01/6370318/t.md

```text
On Wed, 2017-01-25 at 18:25 +0100, Christoph Hellwig wrote:
> -unsigned char *scsi_alloc_sense_buffer(struct Scsi_Host *shost, gfp_t gf=
p_mask,
> -=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0int numa_node)
> +static unsigned char *scsi_alloc_sense_buffer(struct Scsi_Host *shost,
> +=A0=A0=A0=A0=A0=A0=A0gfp_t gfp_mask, int numa_node)
> =A0{
> =A0=A0=A0=A0=A0=A0=A0=A0return kmem_cache_alloc_node(scsi_select_sense_ca=
che(shost), gfp_mask,
> =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0n=
uma_node);
> @@ -697,14 +696,13 @@ static bool scsi_end_request(struct request *req, i=
nt error,
> =A0
> =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0if (bidi_bytes)
> =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0s=
csi_release_bidi_buffers(cmd);
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0scsi_release_buffers(cmd);
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0scsi_put_command(cmd);
> =A0
> =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0spin_lock_irqsave(q->queu=
e_lock, flags);
> =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0blk_finish_request(req, e=
rror);
> =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0spin_unlock_irqrestore(q-=
>queue_lock, flags);
> =A0
> -=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0scsi_release_buffers(cmd);
> -
> -=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0scsi_put_command(cmd);
> =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0scsi_run_queue(q);
> =A0=A0=A0=A0=A0=A0=A0=A0}

Hello Christoph,

Why=A0have the=A0scsi_release_buffers() and scsi_put_command(cmd) calls bee=
n
moved up? I haven't found an explanation for this change in the patch
description.

Please also consider to remove the cmd->request->special =3D NULL assignmen=
ts
via this patch. Since this patch makes the lifetime of struct scsi_cmnd and
struct request identical these assignments are no longer needed.

This patch introduces the function scsi_exit_rq(). Having two functions
for the single-queue path that release resources (scsi_release_buffers()
and scsi_exit_rq()) is confusing. Since every scsi_release_buffers() call
is followed by a blk_unprep_request() call, have you considered to move
the scsi_release_buffers() call into scsi_unprep_fn() via an additional
patch?

Thanks,

Bart.
```