Re: [PATCH 1/4] scsi_cmnd: Rearrange and shrink some elements

[Boaz Harrosh <bharrosh@panasas.com>]

On Thu, Oct 18 2007 at 10:46 +0200, Matthew Wilcox <matthew@wil.cx> wrote:
> By
>  - rearranging the elements of the scsi_pointer
>  - shrinking and moving the eh_eflags element
>  - turning sc_data_direction into an unsigned char
>  - moving tag
> 
> we achieve a size reduction in scsi_cmnd of 376 to 352 bytes on x86-64
> and from 272 to 260 bytes on i386.
> 
> Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
> ---
>  include/scsi/scsi_cmnd.h |   19 ++++++++-----------
>  1 files changed, 8 insertions(+), 11 deletions(-)
> 
> diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
> index 047ffe6..04fe0d8 100644
> --- a/include/scsi/scsi_cmnd.h
> +++ b/include/scsi/scsi_cmnd.h
> @@ -13,22 +13,21 @@ struct Scsi_Host;
>  struct scsi_device;
>  
>  struct scsi_data_buffer {
> +	struct scatterlist* sglist;
>  	unsigned length;
>  	int resid;
>  	unsigned short sg_count;
>  	unsigned short alloc_sg_count;
> -	struct scatterlist* sglist;
>  };
>  
>  /* embedded in scsi_cmnd */
>  struct scsi_pointer {
>  	char *ptr;		/* data pointer */
> -	int this_residual;	/* left in this buffer */
>  	struct scatterlist *buffer;	/* which buffer */
> +	dma_addr_t dma_handle;
> +	int this_residual;	/* left in this buffer */
>  	int buffers_residual;	/* how many buffers left */
>  
> -        dma_addr_t dma_handle;
> -
>  	volatile int Status;
>  	volatile int Message;
>  	volatile int have_data_in;
> @@ -40,7 +39,6 @@ struct scsi_cmnd {
>  	struct scsi_device *device;
>  	struct list_head list;  /* scsi_cmnd participates in queue lists */
>  	struct list_head eh_entry; /* entry for the host eh_cmd_q */
> -	int eh_eflags;		/* Used by error handlr */
>  
>  	/*
>  	 * A SCSI Command is assigned a nonzero serial_number before passed
> @@ -64,7 +62,9 @@ struct scsi_cmnd {
>  	int timeout_per_command;
>  
>  	unsigned char cmd_len;
> -	enum dma_data_direction sc_data_direction;
> +	unsigned char eh_eflags;		/* Used by error handler */
> +	unsigned char sc_data_direction;	/* enum dma_data_direction */
> +	unsigned char tag;			/* SCSI-II queued command tag */
>  
>  	/* These elements define the operation we are about to perform */
>  #define MAX_COMMAND_SIZE	16
> @@ -82,8 +82,7 @@ struct scsi_cmnd {
>  				   reconnects.   Probably == sector
>  				   size */
>  
> -	struct request *request;	/* The command we are
> -				   	   working on */
> +	struct request *request;	/* The command we are working on */
>  
>  #define SCSI_SENSE_BUFFERSIZE 	96
>  	unsigned char sense_buffer[SCSI_SENSE_BUFFERSIZE];
> @@ -111,8 +110,6 @@ struct scsi_cmnd {
>  
>  	int result;		/* Status code from lower level driver */
>  
> -	unsigned char tag;	/* SCSI-II queued command tag */
> -
>  	union {
>  		struct scsi_data_buffer sdb;
>  		/*
> @@ -121,11 +118,11 @@ struct scsi_cmnd {
>  		 *        of struct scsi_data_buffer members.
>  		 */
>  		struct {
> +			void __deprecated *request_buffer;
>  			unsigned __deprecated request_bufflen;
>  			int __deprecated resid;
>  			unsigned short __deprecated use_sg;
>  			unsigned short __deprecated place_holder_sg_alloc;
> -			void __deprecated *request_buffer;
>  		};
>  	};
>  };
Sorry again...
Please redo that patch ontop of patch [33/33]
http://www.spinics.net/lists/linux-scsi/msg20327.html

Again sorry, It was getting late and people where
waiting for me, so I just plain forgot to include
it.

Boaz