Martin K. Petersen wrote:
> 1 file changed, 67 insertions(+)
> drivers/scsi/sd.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>
>
> Make storage devices that support the Block Limits VPD export the
> optimal transfer length granularity and the optimal transfer length to
> the block layer.
>
> Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
>
> ---
>
> diff -r c7132bad88f3 -r dba6ce5d97b8 drivers/scsi/sd.c
> --- a/drivers/scsi/sd.c Thu Jun 05 01:07:51 2008 -0400
> +++ b/drivers/scsi/sd.c Thu Jun 05 01:07:51 2008 -0400
> @@ -1534,6 +1534,72 @@
> sdkp->DPOFUA = 0;
> }
>
> +static int sd_vpd_inquiry(struct scsi_disk *sdkp, unsigned char *buffer, u8 page, u8 len)
> +{
> + int result;
> + unsigned char cmd[16];
> + struct scsi_sense_hdr sshdr;
> +
> + memset(cmd, 0, 16);
> + cmd[0] = INQUIRY;
> + cmd[1] = 1; /* EVPD */
> + cmd[2] = page; /* VPD page */
> + cmd[3] = len;
> +
> + result = scsi_execute_req(sdkp->device, cmd, DMA_FROM_DEVICE, buffer,
> + len, &sshdr, SD_TIMEOUT, SD_MAX_RETRIES);
> +
> + if (media_not_present(sdkp, &sshdr))
> + return -EIO;
> +
> + if (result) {
> + sd_printk(KERN_ERR, sdkp, "EVPD Inquiry failed\n");
> + return -EIO;
> + }
> +
> + if (buffer[1] != page) {
> + sd_printk(KERN_ERR, sdkp, "Page code not %2x (%2x)\n", page,
> + buffer[1]);
> + return -EIO;
> + }
> +
> + return buffer[3];
> +}
> +
> +/**
> + * sd_block_limits - Query disk device for preferred I/O sizes.
> + * @disk: disk to query
> + * @buffer: temporary buffer to store inquiry response in
> + */
> +static void sd_block_limits(struct scsi_disk *sdkp, unsigned char *buffer)
> +{
> + int result, i, bl_found;
> +
> + bl_found = 0;
> + result = sd_vpd_inquiry(sdkp, buffer, 0x0, 32); /* Supported Pages list */
> +
> + if (result < 0 || buffer[4] != 0)
> + return;
> +
> + for (i = 0 ; i < buffer[3] ; i++)
> + if (buffer[4+i] == 0xb0)
> + bl_found = 1;
> +
> + if (bl_found == 0)
> + return;
> +
> + result = sd_vpd_inquiry(sdkp, buffer, 0xb0, 16); /* Block Limits VPD */
> +
> + if (result < 0 || buffer[3] != 12)
> + return;
> +
> + disk_set_io_hints(sdkp->disk, 0, ((buffer[6] << 8) | buffer[7])
> + * sdkp->device->sector_size,
> + ((buffer[12] << 24) | (buffer[13] << 16)
> + | (buffer[14] << 8) | buffer[15])
> + * sdkp->device->sector_size);
> +}
> +
be16_to_cpup((__be16 *)&buffer[6]) and
be32_to_cpup((__be32 *)&buffer[12]) would be more readable for me.
(And defined to nothing on BE systems). Look how the standard aligned
everything nicely for us.
> /**
> * sd_revalidate_disk - called the first time a new disk is seen,
> * performs disk spin up, read_capacity, etc.
> @@ -1579,6 +1645,7 @@
> */
> if (sdkp->media_present) {
> sd_read_capacity(sdkp, buffer);
> + sd_block_limits(sdkp, buffer);
> sd_read_write_protect_flag(sdkp, buffer);
> sd_read_cache_type(sdkp, buffer);
> }
>
>
> --
Just my $0.017
Boaz
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