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From: Cornelia Huck <cohuck@redhat.com>
To: Eric Farman <farman@linux.ibm.com>
Cc: Farhan Ali <alifm@linux.ibm.com>,
	Halil Pasic <pasic@linux.ibm.com>,
	linux-s390@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [PATCH v2 6/9] vfio-ccw: Adjust the first IDAW outside of the nested loops
Date: Thu, 13 Jun 2019 18:02:49 +0200
Message-ID: <20190613180249.1f26258d.cohuck@redhat.com> (raw)
In-Reply-To: <20190606202831.44135-7-farman@linux.ibm.com>

On Thu,  6 Jun 2019 22:28:28 +0200
Eric Farman <farman@linux.ibm.com> wrote:

> Now that pfn_array_table[] is always an array of 1, it seems silly to
> check for the very first entry in an array in the middle of two nested
> loops, since we know it'll only ever happen once.
> 
> Let's move this outside the loops to simplify things, even though
> the "k" variable is still necessary.
> 
> Signed-off-by: Eric Farman <farman@linux.ibm.com>
> ---
>  drivers/s390/cio/vfio_ccw_cp.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c
> index 86a0e76ef2b5..ab9f8f0d1b44 100644
> --- a/drivers/s390/cio/vfio_ccw_cp.c
> +++ b/drivers/s390/cio/vfio_ccw_cp.c
> @@ -201,11 +201,12 @@ static inline void pfn_array_table_idal_create_words(
>  		pa = pat->pat_pa + i;
>  		for (j = 0; j < pa->pa_nr; j++) {
>  			idaws[k] = pa->pa_pfn[j] << PAGE_SHIFT;
> -			if (k == 0)
> -				idaws[k] += pa->pa_iova & (PAGE_SIZE - 1);
>  			k++;
>  		}
>  	}
> +
> +	/* Adjust the first IDAW, since it may not start on a page boundary */
> +	idaws[0] += pat->pat_pa->pa_iova & (PAGE_SIZE - 1);
>  }
>  
>  

Also +1 to adding a nice explaining comment :)

Reviewed-by: Cornelia Huck <cohuck@redhat.com>

  reply index

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-06 20:28 [PATCH v2 0/9] s390: vfio-ccw code rework Eric Farman
2019-06-06 20:28 ` [PATCH v2 1/9] s390/cio: Squash cp_free() and cp_unpin_free() Eric Farman
2019-06-12 11:07   ` Cornelia Huck
2019-06-06 20:28 ` [PATCH v2 2/9] s390/cio: Refactor the routine that handles TIC CCWs Eric Farman
2019-06-12 11:17   ` Cornelia Huck
2019-06-06 20:28 ` [PATCH v2 3/9] s390/cio: Generalize the TIC handler Eric Farman
2019-06-12 11:18   ` Cornelia Huck
2019-06-06 20:28 ` [PATCH v2 4/9] s390/cio: Use generalized CCW handler in cp_init() Eric Farman
2019-06-12 11:18   ` Cornelia Huck
2019-06-06 20:28 ` [PATCH v2 5/9] vfio-ccw: Rearrange pfn_array and pfn_array_table arrays Eric Farman
2019-06-13 16:02   ` Cornelia Huck
2019-06-06 20:28 ` [PATCH v2 6/9] vfio-ccw: Adjust the first IDAW outside of the nested loops Eric Farman
2019-06-13 16:02   ` Cornelia Huck [this message]
2019-06-06 20:28 ` [PATCH v2 7/9] vfio-ccw: Remove pfn_array_table Eric Farman
2019-06-13 16:03   ` Cornelia Huck
2019-06-06 20:28 ` [PATCH v2 8/9] vfio-ccw: Rearrange IDAL allocation in direct CCW Eric Farman
2019-06-14  9:42   ` Cornelia Huck
2019-06-06 20:28 ` [PATCH v2 9/9] s390/cio: Combine direct and indirect CCW paths Eric Farman
2019-06-14 10:01   ` Cornelia Huck
2019-06-14 10:30     ` Eric Farman
2019-06-14 10:03 ` [PATCH v2 0/9] s390: vfio-ccw code rework Cornelia Huck
2019-06-17 13:32 ` Cornelia Huck

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