[libata] scsi: implement MODE SELECT command
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. The set of changeable parameters answered by MODE SENSE is also adjusted accordingly. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
This commit is contained in:
Paolo Bonzini
Jeff Garzik
Родитель
6ca8e79466
Коммит
1b26d29ccd
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@ -2243,7 +2243,7 @@ static void modecpy(u8 *dest, const u8 *src, int n, bool changeable)
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static unsigned int ata_msense_caching(u16 *id, u8 *buf, bool changeable)
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{
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modecpy(buf, def_cache_mpage, sizeof(def_cache_mpage), changeable);
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if (!changeable && ata_id_wcache_enabled(id))
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if (changeable || ata_id_wcache_enabled(id))
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buf[2] |= (1 << 2); /* write cache enable */
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if (!changeable && !ata_id_rahead_enabled(id))
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buf[12] |= (1 << 5); /* disable read ahead */
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@ -3106,6 +3106,188 @@ static unsigned int ata_scsi_write_same_xlat(struct ata_queued_cmd *qc)
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return 1;
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}
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/**
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* ata_mselect_caching - Simulate MODE SELECT for caching info page
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* @qc: Storage for translated ATA taskfile
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* @buf: input buffer
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* @len: number of valid bytes in the input buffer
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*
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* Prepare a taskfile to modify caching information for the device.
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*
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* LOCKING:
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* None.
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*/
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static int ata_mselect_caching(struct ata_queued_cmd *qc,
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const u8 *buf, int len)
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{
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struct ata_taskfile *tf = &qc->tf;
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struct ata_device *dev = qc->dev;
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char mpage[CACHE_MPAGE_LEN];
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u8 wce;
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/*
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* The first two bytes of def_cache_mpage are a header, so offsets
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* in mpage are off by 2 compared to buf. Same for len.
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*/
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if (len != CACHE_MPAGE_LEN - 2)
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return -EINVAL;
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wce = buf[0] & (1 << 2);
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/*
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* Check that read-only bits are not modified.
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*/
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ata_msense_caching(dev->id, mpage, false);
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mpage[2] &= ~(1 << 2);
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mpage[2] |= wce;
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if (memcmp(mpage + 2, buf, CACHE_MPAGE_LEN - 2) != 0)
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return -EINVAL;
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tf->flags |= ATA_TFLAG_DEVICE | ATA_TFLAG_ISADDR;
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tf->protocol = ATA_PROT_NODATA;
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tf->nsect = 0;
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tf->command = ATA_CMD_SET_FEATURES;
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tf->feature = wce ? SETFEATURES_WC_ON : SETFEATURES_WC_OFF;
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return 0;
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}
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/**
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* ata_scsiop_mode_select - Simulate MODE SELECT 6, 10 commands
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* @qc: Storage for translated ATA taskfile
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*
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* Converts a MODE SELECT command to an ATA SET FEATURES taskfile.
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* Assume this is invoked for direct access devices (e.g. disks) only.
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* There should be no block descriptor for other device types.
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*
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* LOCKING:
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* spin_lock_irqsave(host lock)
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*/
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static unsigned int ata_scsi_mode_select_xlat(struct ata_queued_cmd *qc)
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{
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struct scsi_cmnd *scmd = qc->scsicmd;
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const u8 *cdb = scmd->cmnd;
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const u8 *p;
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u8 pg, spg;
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unsigned six_byte, pg_len, hdr_len, bd_len;
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int len;
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VPRINTK("ENTER\n");
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six_byte = (cdb[0] == MODE_SELECT);
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if (six_byte) {
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if (scmd->cmd_len < 5)
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goto invalid_fld;
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len = cdb[4];
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hdr_len = 4;
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} else {
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if (scmd->cmd_len < 9)
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goto invalid_fld;
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len = (cdb[7] << 8) + cdb[8];
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hdr_len = 8;
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}
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/* We only support PF=1, SP=0. */
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if ((cdb[1] & 0x11) != 0x10)
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goto invalid_fld;
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/* Test early for possible overrun. */
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if (!scsi_sg_count(scmd) || scsi_sglist(scmd)->length < len)
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goto invalid_param_len;
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p = page_address(sg_page(scsi_sglist(scmd)));
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/* Move past header and block descriptors. */
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if (len < hdr_len)
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goto invalid_param_len;
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if (six_byte)
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bd_len = p[3];
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else
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bd_len = (p[6] << 8) + p[7];
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len -= hdr_len;
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p += hdr_len;
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if (len < bd_len)
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goto invalid_param_len;
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if (bd_len != 0 && bd_len != 8)
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goto invalid_param;
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len -= bd_len;
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p += bd_len;
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if (len == 0)
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goto skip;
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/* Parse both possible formats for the mode page headers. */
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pg = p[0] & 0x3f;
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if (p[0] & 0x40) {
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if (len < 4)
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goto invalid_param_len;
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spg = p[1];
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pg_len = (p[2] << 8) | p[3];
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p += 4;
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len -= 4;
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} else {
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if (len < 2)
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goto invalid_param_len;
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spg = 0;
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pg_len = p[1];
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p += 2;
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len -= 2;
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}
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/*
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* No mode subpages supported (yet) but asking for _all_
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* subpages may be valid
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*/
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if (spg && (spg != ALL_SUB_MPAGES))
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goto invalid_param;
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if (pg_len > len)
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goto invalid_param_len;
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switch (pg) {
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case CACHE_MPAGE:
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if (ata_mselect_caching(qc, p, pg_len) < 0)
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goto invalid_param;
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break;
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default: /* invalid page code */
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goto invalid_param;
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}
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/*
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* Only one page has changeable data, so we only support setting one
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* page at a time.
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*/
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if (len > pg_len)
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goto invalid_param;
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return 0;
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invalid_fld:
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/* "Invalid field in CDB" */
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ata_scsi_set_sense(scmd, ILLEGAL_REQUEST, 0x24, 0x0);
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return 1;
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invalid_param:
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/* "Invalid field in parameter list" */
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ata_scsi_set_sense(scmd, ILLEGAL_REQUEST, 0x26, 0x0);
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return 1;
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invalid_param_len:
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/* "Parameter list length error" */
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ata_scsi_set_sense(scmd, ILLEGAL_REQUEST, 0x1a, 0x0);
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return 1;
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skip:
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scmd->result = SAM_STAT_GOOD;
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return 1;
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}
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/**
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* ata_get_xlat_func - check if SCSI to ATA translation is possible
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* @dev: ATA device
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@ -3146,6 +3328,11 @@ static inline ata_xlat_func_t ata_get_xlat_func(struct ata_device *dev, u8 cmd)
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case ATA_16:
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return ata_scsi_pass_thru;
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case MODE_SELECT:
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case MODE_SELECT_10:
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return ata_scsi_mode_select_xlat;
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break;
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case START_STOP:
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return ata_scsi_start_stop_xlat;
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}
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@ -3338,11 +3525,6 @@ void ata_scsi_simulate(struct ata_device *dev, struct scsi_cmnd *cmd)
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ata_scsi_rbuf_fill(&args, ata_scsiop_mode_sense);
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break;
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case MODE_SELECT: /* unconditionally return */
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case MODE_SELECT_10: /* bad-field-in-cdb */
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ata_scsi_invalid_field(cmd);
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break;
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case READ_CAPACITY:
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ata_scsi_rbuf_fill(&args, ata_scsiop_read_cap);
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break;
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