Hello. On 07/04/2012 03:13 PM, Paolo Bonzini wrote: > The cache_type file in sysfs lets users configure the disk cache in > write-through or write-back modes. However, ata disks do not support > writing to the file because they do not implement the MODE SELECT > command. > This patch adds a translation from MODE SELECT (for the caching page > only) to the ATA SET FEATURES command. > Cc: Jeff Garzik <jgarzik@xxxxxxxxx> > Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> > --- > drivers/ata/libata-scsi.c | 147 +++++++++++++++++++++++++++++++++++++++++++-- > 1 files changed, 142 insertions(+), 5 deletions(-) > diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c > index 41cde45..e7702d3 100644 > --- a/drivers/ata/libata-scsi.c > +++ b/drivers/ata/libata-scsi.c > @@ -3081,6 +3081,144 @@ static unsigned int ata_scsi_write_same_xlat(struct ata_queued_cmd *qc) > } > > /** > + * ata_mselect_caching - Simulate MODE SELECT for caching info page > + * @tf: taskfile to be filled > + * @buf: input buffer > + * @len: number of valid bytes in the input buffer > + * > + * Prepare a taskfile to modify caching information for the device. > + * > + * LOCKING: > + * None. > + */ > +static unsigned int ata_mselect_caching(struct ata_taskfile *tf, const u8 *buf, > + int len) > +{ > + u8 wce; Empty line after declaration block wouldn't hurt... > + if (len == 0) > + return 1; > + > + /* > + * The first two bytes are a header, so offsets here are 2 less > + * than in ata_msense_caching. > + */ > + wce = buf[0] & (1 << 2); Perhaps it's worth denying the command if the other page fields dfifer from 'def_cache_mpage' (i.e. all zeros)? > +/** > + * ata_scsi_mode_select_xlat - Translate MODE SELECT 6, 10 commands > + * @qc: Storage for translated ATA taskfile > + * > + * Converts a MODE SELECT command to an ATA SET FEATURES taskfile. > + * Assume this is invoked for direct access devices (e.g. disks) only. > + * There should be no block descriptor for other device types. > + * > + * LOCKING: > + * spin_lock_irqsave(host lock) > + */ > +static unsigned int ata_scsi_mode_select_xlat(struct ata_queued_cmd *qc) > +{ > + struct scsi_cmnd *scmd = qc->scsicmd; > + struct ata_taskfile *tf = &qc->tf; > + const u8 *cdb = scmd->cmnd; > + const u8 *p; > + u8 pg, spg; > + unsigned six_byte, pg_len; > + int len; > + > + VPRINTK("ENTER\n"); > + > + /* > + * Get the command buffer. > + */ > + if (!scsi_sg_count(scmd)) > + goto invalid_fld; > + > + p = page_address(sg_page(scsi_sglist(scmd))); > + > + six_byte = (cdb[0] == MODE_SELECT); > + if (six_byte) { > + if (scmd->cmd_len < 5) Not 6? > + goto invalid_fld; > + > + len = cdb[4]; > + } else { > + if (scmd->cmd_len < 9) Not 10? And ata_scsiop_mode_sense() don't seem to check this... And I doubt "Invalid field in CDB" is a proper sense code in this situation. > + goto invalid_fld; > + > + len = (cdb[7] << 8) | cdb[8]; > + } > + /* > + * No mode subpages supported (yet) but asking for _all_ > + * subpages may be valid > + */ > + if (spg && (spg != ALL_SUB_MPAGES)) > + goto invalid_fld; > + if (pg_len > len) > + goto invalid_fld; It's valid to have buffer size less than data size. > + switch (pg) { > + case CACHE_MPAGE: > + if (ata_mselect_caching(tf, p, pg_len)) > + goto invalid_fld; > + break; > + > + default: /* invalid page code */ > + goto invalid_fld; Page code is not a part of CDB, hence the sense code you'll return doesn't fit there. > + } > + return 0; > + > + invalid_fld: > + ata_scsi_set_sense(scmd, ILLEGAL_REQUEST, 0x24, 0x0); > + /* "Invalid field in cbd" */ > + return 1; MBR, Sergei -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html