Re: [PATCH update] ieee1394: sbp2: enforce s/g segment size limit

[FUJITA Tomonori]

On Thu, 14 Aug 2008 09:12:01 +0200 (CEST)
Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx> wrote:

> On 14 Aug, FUJITA Tomonori wrote:
> > On Wed, 13 Aug 2008 12:19:59 +0200 (CEST)
> > Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx> wrote:
> >> I keep the original scsi_sg_count to call dma_unmap_sg with it
> >> later.
> > 
> > You need to keep it? You can access to it via scsi_sg_count when
> > calling dma_unmap_sg? Seems that firewire code does.
> 
> Yes, I can easily do it this way; fixed below.
> 
> [...nents in dma_unmap_sg...]
> > This is from Documentation/DMA-mapping.txt
> 
> Right.  How did I forget about that?
> 
> 
> 
> From: Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx>
> Subject: ieee1394: sbp2: remove redundant struct members
> 
> Signed-off-by: Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx>
> ---
>  drivers/ieee1394/sbp2.c |   14 +++++---------
>  drivers/ieee1394/sbp2.h |    4 ----
>  2 files changed, 5 insertions(+), 13 deletions(-)
> 
> Index: linux/drivers/ieee1394/sbp2.c
> ===================================================================
> --- linux.orig/drivers/ieee1394/sbp2.c
> +++ linux/drivers/ieee1394/sbp2.c
> @@ -656,11 +656,11 @@ static struct sbp2_command_info *sbp2uti
>  static void sbp2util_mark_command_completed(struct sbp2_lu *lu,
>  					    struct sbp2_command_info *cmd)
>  {
> -	if (cmd->sg_buffer) {
> -		dma_unmap_sg(lu->ud->ne->host->device.parent, cmd->sg_buffer,
> -			     cmd->sg_count, cmd->sg_dir);
> -		cmd->sg_buffer = NULL;
> -	}
> +	if (scsi_sg_count(cmd->Current_SCpnt) > 0)

static inline unsigned scsi_sg_count(struct scsi_cmnd *cmd)

so 

> +	if (scsi_sg_count(cmd->Current_SCpnt))

make more sense, I think. It looks a nice cleanup except for it.


> +		dma_unmap_sg(lu->ud->ne->host->device.parent,
> +			     scsi_sglist(cmd->Current_SCpnt),
> +			     scsi_sg_count(cmd->Current_SCpnt),
> +			     cmd->Current_SCpnt->sc_data_direction);
>  	list_move_tail(&cmd->list, &lu->cmd_orb_completed);
>  }
>  
> @@ -1505,10 +1505,6 @@ static int sbp2_prep_command_orb_sg(stru
>  	if (n == 0)
>  		return -ENOMEM;
>  
> -	cmd->sg_buffer = sg;
> -	cmd->sg_count = sg_count;
> -	cmd->sg_dir = dma_dir;
> -
>  	orb->data_descriptor_hi = ORB_SET_NODE_ID(hi->host->node_id);
>  	orb->misc |= ORB_SET_DIRECTION(orb_direction);
>  
> Index: linux/drivers/ieee1394/sbp2.h
> ===================================================================
> --- linux.orig/drivers/ieee1394/sbp2.h
> +++ linux/drivers/ieee1394/sbp2.h
> @@ -252,10 +252,6 @@ struct sbp2_command_info {
>  	struct sbp2_unrestricted_page_table
>  		scatter_gather_element[SG_ALL] __attribute__((aligned(8)));
>  	dma_addr_t sge_dma;
> -
> -	struct scatterlist *sg_buffer;
> -	int sg_count;
> -	enum dma_data_direction sg_dir;
>  };
>  
>  /* Per FireWire host */
> 
> 
> -- 
> Stefan Richter
> -=====-==--- =--- -===-
> http://arcgraph.de/sr/
> 
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