Re: [PATCH] libata: (round 5) add support for ATA_16 on ATAPI

[Jeff Garzik <jeff@garzik.org>]

Mark Lord wrote:
> Resending, with a bug fixed, and default ata16_passthru=0.
> 
> This patch adds support for issuing ATA_16 passthru commands
> to ATAPI devices managed by libata.  It requires the previous
> CDB length fix patch.
> 
> A boot/module parameter, "ata16_passthru=1" can be used to
> globally disable this feature, if ever desired.
> 
> Signed-Off-By: Mark :ord <mlord@pobox.com>
> ---
> diff -u --recursive --new-file --exclude-from=old/Documentation/dontdiff 
> old/drivers/ata/libata-core.c new/drivers/ata/libata-core.c
> --- old/drivers/ata/libata-core.c    2007-02-02 12:29:10.000000000 -0500
> +++ new/drivers/ata/libata-core.c    2007-02-02 12:29:03.000000000 -0500
> @@ -82,6 +82,10 @@
> module_param(atapi_dmadir, int, 0444);
> MODULE_PARM_DESC(atapi_dmadir, "Enable ATAPI DMADIR bridge support 
> (0=off, 1=on)");
> 
> +int ata16_passthru = 0;
> +module_param(ata16_passthru, int, 0444);
> +MODULE_PARM_DESC(ata16_passthru, "Enable passthru of SCSI opcode 0x85 
> to ATAPI devices (0=off, 1=on)");
> +
> int libata_fua = 0;
> module_param_named(fua, libata_fua, int, 0444);
> MODULE_PARM_DESC(fua, "FUA support (0=off, 1=on)");
> diff -u --recursive --new-file --exclude-from=old/Documentation/dontdiff 
> old/drivers/ata/libata-scsi.c new/drivers/ata/libata-scsi.c
> --- old/drivers/ata/libata-scsi.c    2007-02-02 12:29:10.000000000 -0500
> +++ new/drivers/ata/libata-scsi.c    2007-02-02 12:29:25.000000000 -0500
> @@ -2688,6 +2688,10 @@
> 
> static inline ata_xlat_func_t ata_get_xlat_func(struct ata_device *dev, 
> u8 cmd)
> {
> +    if (dev->class == ATA_DEV_ATAPI)
> +        if (cmd != ATA_16 || ata16_passthru)
> +            return atapi_xlat;
> +
>     switch (cmd) {
>     case READ_6:
>     case READ_10:
> @@ -2746,27 +2750,28 @@
>                       void (*done)(struct scsi_cmnd *),
>                       struct ata_device *dev)
> {
> -    int rc = 0;
> -
> -    if (unlikely(!scmd->cmd_len || scmd->cmd_len > dev->cdb_len)) {
> -        DPRINTK("bad CDB len=%u, max=%u\n",
> -            scmd->cmd_len, dev->cdb_len);
> +    ata_xlat_func_t xlat_func;
> +    int rc = 0, max_len;
> +    u8 scsi_op = scmd->cmnd[0];
> +
> +    if (scsi_op == ATA_16 && dev->class == ATA_DEV_ATAPI && 
> !ata16_passthru)
> +        max_len = 16;
> +    else
> +        max_len = dev->cdb_len;
> + +    if (unlikely(!scmd->cmd_len || scmd->cmd_len > max_len)) {
> +         DPRINTK("bad CDB len=%u, max=%u\n",
> +             scmd->cmd_len, max_len);

looks like a chompified patch (double '+')


>         scmd->result = DID_ERROR << 16;
>         done(scmd);
>         return 0;
>     }
> 
> -    if (dev->class == ATA_DEV_ATA) {
> -        ata_xlat_func_t xlat_func = ata_get_xlat_func(dev,
> -                                  scmd->cmnd[0]);
> -
> -        if (xlat_func)
> -            rc = ata_scsi_translate(dev, scmd, done, xlat_func);
> -        else
> -            ata_scsi_simulate(dev, scmd, done);
> -    } else
> -        rc = ata_scsi_translate(dev, scmd, done, atapi_xlat);
> -
> +    xlat_func = ata_get_xlat_func(dev, scsi_op);
> +    if (xlat_func)
> +        rc = ata_scsi_translate(dev, scmd, done, xlat_func);
> +    else
> +        ata_scsi_simulate(dev, scmd, done);
>     return rc;


this looks like a bug?  ata_scsi_simulate() should not be called for 
ATAPI devices.