Re: [PATCH 12/13] libata: Report disk alignment and physical block size

[Jeff Garzik <jeff@garzik.org>]

Martin K. Petersen wrote:
> From: Martin K. Petersen <martin.petersen@oracle.com>
> 
> For disks with 4KB sectors, report the correct block size and alignment
> when filling out the READ CAPACITY(16) response.
> 
> This patch is based upon code from Matthew Wilcox' 4KB ATA tree.  I
> fixed the bug I reported a while back caused by ATA and SCSI using
> different approaches to describing the alignment.
> 
> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
> ---
>  drivers/ata/libata-scsi.c |   23 ++++++++++++++++++++++-
>  1 files changed, 22 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
> index 6e4c600..5072003 100644
> --- a/drivers/ata/libata-scsi.c
> +++ b/drivers/ata/libata-scsi.c
> @@ -2376,7 +2376,23 @@ saving_not_supp:
>   */
>  static unsigned int ata_scsiop_read_cap(struct ata_scsi_args *args, u8 *rbuf)
>  {
> -	u64 last_lba = args->dev->n_sectors - 1; /* LBA of the last block */
> +	struct ata_device *dev = args->dev;
> +	u64 last_lba = dev->n_sectors - 1; /* LBA of the last block */
> +	u8 log_per_phys = 0;
> +	u16 lowest_aligned = 0;
> +	u16 word_106 = dev->id[106];
> +	u16 word_209 = dev->id[209];
> +
> +	if ((word_106 & 0xc000) == 0x4000) {
> +		/* Number and offset of logical sectors per physical sector */
> +		if (word_106 & (1 << 13))
> +			log_per_phys = word_106 & 0xf;
> +		if ((word_209 & 0xc000) == 0x4000) {
> +			u16 first = dev->id[209] & 0x3fff;
> +			if (first > 0)
> +				lowest_aligned = (1 << log_per_phys) - first;
> +		}
> +	}
>  
>  	VPRINTK("ENTER\n");
>  
> @@ -2407,6 +2423,11 @@ static unsigned int ata_scsiop_read_cap(struct ata_scsi_args *args, u8 *rbuf)
>  		/* sector size */
>  		rbuf[10] = ATA_SECT_SIZE >> 8;
>  		rbuf[11] = ATA_SECT_SIZE & 0xff;
> +
> +		rbuf[12] = 0;
> +		rbuf[13] = log_per_phys;
> +		rbuf[14] = (lowest_aligned >> 8) & 0x3f;
> +		rbuf[15] = lowest_aligned;

applied