target: Refactor MODE SENSE emulation
Convert spc_emulate_modesense() to use a table of mode pages, rather
than a switch statement. This makes it possible to add more pages
sanely -- in particular we no longer need to make sure we keep the
0x3f (return all mode pages) case in sync.
While we're touching this code, make our MODE SENSE emulation a bit
better in a couple of ways:
- When the initiator passes PC == 1 asking for changeable values,
return all 0s to show we don't support setting anything.
- Return a block descriptor for disk devices.
(nab: fix up device attribute references to use dev->dev_attrib
in for-next code)
Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Roland Dreier
Nicholas Bellinger
parent
1f981de55a
commit
d4b2b86719
@ -639,18 +639,28 @@ out:
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return ret;
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}
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static int spc_modesense_rwrecovery(unsigned char *p)
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static int spc_modesense_rwrecovery(struct se_device *dev, u8 pc, u8 *p)
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{
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p[0] = 0x01;
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p[1] = 0x0a;
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/* No changeable values for now */
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if (pc == 1)
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goto out;
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out:
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return 12;
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}
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static int spc_modesense_control(struct se_device *dev, unsigned char *p)
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static int spc_modesense_control(struct se_device *dev, u8 pc, u8 *p)
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{
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p[0] = 0x0a;
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p[1] = 0x0a;
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/* No changeable values for now */
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if (pc == 1)
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goto out;
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p[2] = 2;
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/*
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* From spc4r23, 7.4.7 Control mode page
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@ -729,20 +739,37 @@ static int spc_modesense_control(struct se_device *dev, unsigned char *p)
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p[9] = 0xff;
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p[11] = 30;
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out:
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return 12;
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}
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static int spc_modesense_caching(struct se_device *dev, unsigned char *p)
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static int spc_modesense_caching(struct se_device *dev, u8 pc, u8 *p)
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{
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p[0] = 0x08;
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p[1] = 0x12;
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/* No changeable values for now */
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if (pc == 1)
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goto out;
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if (dev->dev_attrib.emulate_write_cache > 0)
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p[2] = 0x04; /* Write Cache Enable */
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p[12] = 0x20; /* Disabled Read Ahead */
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out:
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return 20;
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}
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static struct {
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uint8_t page;
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uint8_t subpage;
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int (*emulate)(struct se_device *, u8, unsigned char *);
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} modesense_handlers[] = {
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{ .page = 0x01, .subpage = 0x00, .emulate = spc_modesense_rwrecovery },
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{ .page = 0x08, .subpage = 0x00, .emulate = spc_modesense_caching },
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{ .page = 0x0a, .subpage = 0x00, .emulate = spc_modesense_control },
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};
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static void spc_modesense_write_protect(unsigned char *buf, int type)
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{
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/*
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@ -769,77 +796,167 @@ static void spc_modesense_dpofua(unsigned char *buf, int type)
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}
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}
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static int spc_modesense_blockdesc(unsigned char *buf, u64 blocks, u32 block_size)
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{
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*buf++ = 8;
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put_unaligned_be32(min(blocks, 0xffffffffull), buf);
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buf += 4;
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put_unaligned_be32(block_size, buf);
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return 9;
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}
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static int spc_modesense_long_blockdesc(unsigned char *buf, u64 blocks, u32 block_size)
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{
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if (blocks <= 0xffffffff)
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return spc_modesense_blockdesc(buf + 3, blocks, block_size) + 3;
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*buf++ = 1; /* LONGLBA */
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buf += 2;
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*buf++ = 16;
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put_unaligned_be64(blocks, buf);
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buf += 12;
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put_unaligned_be32(block_size, buf);
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return 17;
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}
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static int spc_emulate_modesense(struct se_cmd *cmd)
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{
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struct se_device *dev = cmd->se_dev;
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char *cdb = cmd->t_task_cdb;
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unsigned char *rbuf;
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unsigned char *buf, *map_buf;
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int type = dev->transport->get_device_type(dev);
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int ten = (cmd->t_task_cdb[0] == MODE_SENSE_10);
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u32 offset = ten ? 8 : 4;
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bool dbd = !!(cdb[1] & 0x08);
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bool llba = ten ? !!(cdb[1] & 0x10) : false;
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u8 pc = cdb[2] >> 6;
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u8 page = cdb[2] & 0x3f;
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u8 subpage = cdb[3];
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int length = 0;
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unsigned char buf[SE_MODE_PAGE_BUF];
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int ret;
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int i;
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memset(buf, 0, SE_MODE_PAGE_BUF);
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map_buf = transport_kmap_data_sg(cmd);
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switch (cdb[2] & 0x3f) {
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case 0x01:
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length = spc_modesense_rwrecovery(&buf[offset]);
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break;
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case 0x08:
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length = spc_modesense_caching(dev, &buf[offset]);
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break;
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case 0x0a:
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length = spc_modesense_control(dev, &buf[offset]);
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break;
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case 0x3f:
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length = spc_modesense_rwrecovery(&buf[offset]);
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length += spc_modesense_caching(dev, &buf[offset+length]);
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length += spc_modesense_control(dev, &buf[offset+length]);
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break;
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default:
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pr_err("MODE SENSE: unimplemented page/subpage: 0x%02x/0x%02x\n",
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cdb[2] & 0x3f, cdb[3]);
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cmd->scsi_sense_reason = TCM_UNKNOWN_MODE_PAGE;
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return -EINVAL;
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}
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offset += length;
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if (ten) {
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offset -= 2;
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buf[0] = (offset >> 8) & 0xff;
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buf[1] = offset & 0xff;
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offset += 2;
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if ((cmd->se_lun->lun_access & TRANSPORT_LUNFLAGS_READ_ONLY) ||
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(cmd->se_deve &&
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(cmd->se_deve->lun_flags & TRANSPORT_LUNFLAGS_READ_ONLY)))
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spc_modesense_write_protect(&buf[3], type);
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if ((dev->dev_attrib.emulate_write_cache > 0) &&
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(dev->dev_attrib.emulate_fua_write > 0))
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spc_modesense_dpofua(&buf[3], type);
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/*
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* If SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC is not set, then we
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* know we actually allocated a full page. Otherwise, if the
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* data buffer is too small, allocate a temporary buffer so we
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* don't have to worry about overruns in all our INQUIRY
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* emulation handling.
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*/
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if (cmd->data_length < SE_MODE_PAGE_BUF &&
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(cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC)) {
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buf = kzalloc(SE_MODE_PAGE_BUF, GFP_KERNEL);
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if (!buf) {
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transport_kunmap_data_sg(cmd);
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cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
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return -ENOMEM;
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}
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} else {
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offset -= 1;
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buf[0] = offset & 0xff;
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offset += 1;
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if ((cmd->se_lun->lun_access & TRANSPORT_LUNFLAGS_READ_ONLY) ||
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(cmd->se_deve &&
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(cmd->se_deve->lun_flags & TRANSPORT_LUNFLAGS_READ_ONLY)))
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spc_modesense_write_protect(&buf[2], type);
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if ((dev->dev_attrib.emulate_write_cache > 0) &&
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(dev->dev_attrib.emulate_fua_write > 0))
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spc_modesense_dpofua(&buf[2], type);
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buf = map_buf;
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}
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rbuf = transport_kmap_data_sg(cmd);
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if (rbuf) {
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memcpy(rbuf, buf, min(offset, cmd->data_length));
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transport_kunmap_data_sg(cmd);
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length = ten ? 2 : 1;
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/* DEVICE-SPECIFIC PARAMETER */
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if ((cmd->se_lun->lun_access & TRANSPORT_LUNFLAGS_READ_ONLY) ||
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(cmd->se_deve &&
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(cmd->se_deve->lun_flags & TRANSPORT_LUNFLAGS_READ_ONLY)))
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spc_modesense_write_protect(&buf[length], type);
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if ((dev->dev_attrib.emulate_write_cache > 0) &&
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(dev->dev_attrib.emulate_fua_write > 0))
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spc_modesense_dpofua(&buf[length], type);
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++length;
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/* BLOCK DESCRIPTOR */
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/*
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* For now we only include a block descriptor for disk (SBC)
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* devices; other command sets use a slightly different format.
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*/
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if (!dbd && type == TYPE_DISK) {
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u64 blocks = dev->transport->get_blocks(dev);
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u32 block_size = dev->dev_attrib.block_size;
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if (ten) {
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if (llba) {
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length += spc_modesense_long_blockdesc(&buf[length],
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blocks, block_size);
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} else {
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length += 3;
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length += spc_modesense_blockdesc(&buf[length],
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blocks, block_size);
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}
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} else {
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length += spc_modesense_blockdesc(&buf[length], blocks,
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block_size);
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}
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} else {
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if (ten)
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length += 4;
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else
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length += 1;
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}
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if (page == 0x3f) {
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if (subpage != 0x00 && subpage != 0xff) {
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cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
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length = -EINVAL;
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goto out;
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}
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for (i = 0; i < ARRAY_SIZE(modesense_handlers); ++i) {
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/*
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* Tricky way to say all subpage 00h for
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* subpage==0, all subpages for subpage==0xff
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* (and we just checked above that those are
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* the only two possibilities).
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*/
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if ((modesense_handlers[i].subpage & ~subpage) == 0) {
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ret = modesense_handlers[i].emulate(dev, pc, &buf[length]);
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if (!ten && length + ret >= 255)
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break;
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length += ret;
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}
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}
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goto set_length;
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}
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for (i = 0; i < ARRAY_SIZE(modesense_handlers); ++i)
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if (modesense_handlers[i].page == page &&
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modesense_handlers[i].subpage == subpage) {
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length += modesense_handlers[i].emulate(dev, pc, &buf[length]);
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goto set_length;
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}
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/*
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* We don't intend to implement:
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* - obsolete page 03h "format parameters" (checked by Solaris)
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*/
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if (page != 0x03)
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pr_err("MODE SENSE: unimplemented page/subpage: 0x%02x/0x%02x\n",
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page, subpage);
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cmd->scsi_sense_reason = TCM_UNKNOWN_MODE_PAGE;
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return -EINVAL;
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set_length:
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if (ten)
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put_unaligned_be16(length - 2, buf);
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else
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buf[0] = length - 1;
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out:
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if (buf != map_buf) {
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memcpy(map_buf, buf, cmd->data_length);
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kfree(buf);
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}
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transport_kunmap_data_sg(cmd);
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target_complete_cmd(cmd, GOOD);
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return 0;
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}
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