From: Roland Dreier <roland@xxxxxxxxxxxxxxx>
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.
Signed-off-by: Roland Dreier <roland@xxxxxxxxxxxxxxx>
---
drivers/target/target_core_spc.c | 235 ++++++++++++++++++++++++++++----------
1 file changed, 176 insertions(+), 59 deletions(-)
diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c
index 9229bd9..bc244d7 100644
--- a/drivers/target/target_core_spc.c
+++ b/drivers/target/target_core_spc.c
@@ -647,18 +647,28 @@ out:
return ret;
}
-static int spc_modesense_rwrecovery(unsigned char *p)
+static int spc_modesense_rwrecovery(struct se_device *dev, u8 pc, u8 *p)
{
p[0] = 0x01;
p[1] = 0x0a;
+ /* No changeable values for now */
+ if (pc == 1)
+ goto out;
+
+out:
return 12;
}
-static int spc_modesense_control(struct se_device *dev, unsigned char *p)
+static int spc_modesense_control(struct se_device *dev, u8 pc, u8 *p)
{
p[0] = 0x0a;
p[1] = 0x0a;
+
+ /* No changeable values for now */
+ if (pc == 1)
+ goto out;
+
p[2] = 2;
/*
* From spc4r23, 7.4.7 Control mode page
@@ -737,20 +747,37 @@ static int spc_modesense_control(struct se_device *dev, unsigned char *p)
p[9] = 0xff;
p[11] = 30;
+out:
return 12;
}
-static int spc_modesense_caching(struct se_device *dev, unsigned char *p)
+static int spc_modesense_caching(struct se_device *dev, u8 pc, u8 *p)
{
p[0] = 0x08;
p[1] = 0x12;
+
+ /* No changeable values for now */
+ if (pc == 1)
+ goto out;
+
if (dev->se_sub_dev->se_dev_attrib.emulate_write_cache > 0)
p[2] = 0x04; /* Write Cache Enable */
p[12] = 0x20; /* Disabled Read Ahead */
+out:
return 20;
}
+static struct {
+ uint8_t page;
+ uint8_t subpage;
+ int (*emulate)(struct se_device *, u8, unsigned char *);
+} modesense_handlers[] = {
+ { .page = 0x01, .subpage = 0x00, .emulate = spc_modesense_rwrecovery },
+ { .page = 0x08, .subpage = 0x00, .emulate = spc_modesense_caching },
+ { .page = 0x0a, .subpage = 0x00, .emulate = spc_modesense_control },
+};
+
static void spc_modesense_write_protect(unsigned char *buf, int type)
{
/*
@@ -777,77 +804,167 @@ static void spc_modesense_dpofua(unsigned char *buf, int type)
}
}
+static int spc_modesense_blockdesc(unsigned char *buf, u64 blocks, u32 block_size)
+{
+ *buf++ = 8;
+ put_unaligned_be32(min(blocks, 0xffffffffull), buf);
+ buf += 4;
+ put_unaligned_be32(block_size, buf);
+ return 9;
+}
+
+static int spc_modesense_long_blockdesc(unsigned char *buf, u64 blocks, u32 block_size)
+{
+ if (blocks <= 0xffffffff)
+ return spc_modesense_blockdesc(buf + 3, blocks, block_size) + 3;
+
+ *buf++ = 1; /* LONGLBA */
+ buf += 2;
+ *buf++ = 16;
+ put_unaligned_be64(blocks, buf);
+ buf += 12;
+ put_unaligned_be32(block_size, buf);
+
+ return 17;
+}
+
static int spc_emulate_modesense(struct se_cmd *cmd)
{
struct se_device *dev = cmd->se_dev;
char *cdb = cmd->t_task_cdb;
- unsigned char *rbuf;
+ unsigned char *buf, *map_buf;
int type = dev->transport->get_device_type(dev);
int ten = (cmd->t_task_cdb[0] == MODE_SENSE_10);
- u32 offset = ten ? 8 : 4;
+ bool dbd = !!(cdb[1] & 0x08);
+ bool llba = ten ? !!(cdb[1] & 0x10) : false;
+ u8 pc = cdb[2] >> 6;
+ u8 page = cdb[2] & 0x3f;
+ u8 subpage = cdb[3];
int length = 0;
- unsigned char buf[SE_MODE_PAGE_BUF];
+ int ret;
+ int i;
- memset(buf, 0, SE_MODE_PAGE_BUF);
+ map_buf = transport_kmap_data_sg(cmd);
- switch (cdb[2] & 0x3f) {
- case 0x01:
- length = spc_modesense_rwrecovery(&buf[offset]);
- break;
- case 0x08:
- length = spc_modesense_caching(dev, &buf[offset]);
- break;
- case 0x0a:
- length = spc_modesense_control(dev, &buf[offset]);
- break;
- case 0x3f:
- length = spc_modesense_rwrecovery(&buf[offset]);
- length += spc_modesense_caching(dev, &buf[offset+length]);
- length += spc_modesense_control(dev, &buf[offset+length]);
- break;
- default:
- pr_err("MODE SENSE: unimplemented page/subpage: 0x%02x/0x%02x\n",
- cdb[2] & 0x3f, cdb[3]);
- cmd->scsi_sense_reason = TCM_UNKNOWN_MODE_PAGE;
- return -EINVAL;
+ /*
+ * If SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC is not set, then we
+ * know we actually allocated a full page. Otherwise, if the
+ * data buffer is too small, allocate a temporary buffer so we
+ * don't have to worry about overruns in all our INQUIRY
+ * emulation handling.
+ */
+ if (cmd->data_length < SE_MODE_PAGE_BUF &&
+ (cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC)) {
+ buf = kzalloc(SE_MODE_PAGE_BUF, GFP_KERNEL);
+ if (!buf) {
+ transport_kunmap_data_sg(cmd);
+ cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+ return -ENOMEM;
+ }
+ } else {
+ buf = map_buf;
}
- offset += length;
-
- if (ten) {
- offset -= 2;
- buf[0] = (offset >> 8) & 0xff;
- buf[1] = offset & 0xff;
- offset += 2;
-
- if ((cmd->se_lun->lun_access & TRANSPORT_LUNFLAGS_READ_ONLY) ||
- (cmd->se_deve &&
- (cmd->se_deve->lun_flags & TRANSPORT_LUNFLAGS_READ_ONLY)))
- spc_modesense_write_protect(&buf[3], type);
-
- if ((dev->se_sub_dev->se_dev_attrib.emulate_write_cache > 0) &&
- (dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0))
- spc_modesense_dpofua(&buf[3], type);
+
+ length = ten ? 2 : 1;
+
+ /* DEVICE-SPECIFIC PARAMETER */
+ if ((cmd->se_lun->lun_access & TRANSPORT_LUNFLAGS_READ_ONLY) ||
+ (cmd->se_deve &&
+ (cmd->se_deve->lun_flags & TRANSPORT_LUNFLAGS_READ_ONLY)))
+ spc_modesense_write_protect(&buf[length], type);
+
+ if ((dev->se_sub_dev->se_dev_attrib.emulate_write_cache > 0) &&
+ (dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0))
+ spc_modesense_dpofua(&buf[length], type);
+
+ ++length;
+
+ /* BLOCK DESCRIPTOR */
+
+ /*
+ * For now we only include a block descriptor for disk (SBC)
+ * devices; other command sets use a slightly different format.
+ */
+ if (!dbd && type == TYPE_DISK) {
+ u64 blocks = dev->transport->get_blocks(dev);
+ u32 block_size = dev->se_sub_dev->se_dev_attrib.block_size;
+
+ if (ten) {
+ if (llba) {
+ length += spc_modesense_long_blockdesc(&buf[length],
+ blocks, block_size);
+ } else {
+ length += 3;
+ length += spc_modesense_blockdesc(&buf[length],
+ blocks, block_size);
+ }
+ } else {
+ length += spc_modesense_blockdesc(&buf[length], blocks,
+ block_size);
+ }
} else {
- offset -= 1;
- buf[0] = offset & 0xff;
- offset += 1;
-
- if ((cmd->se_lun->lun_access & TRANSPORT_LUNFLAGS_READ_ONLY) ||
- (cmd->se_deve &&
- (cmd->se_deve->lun_flags & TRANSPORT_LUNFLAGS_READ_ONLY)))
- spc_modesense_write_protect(&buf[2], type);
-
- if ((dev->se_sub_dev->se_dev_attrib.emulate_write_cache > 0) &&
- (dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0))
- spc_modesense_dpofua(&buf[2], type);
+ if (ten)
+ length += 4;
+ else
+ length += 1;
}
- rbuf = transport_kmap_data_sg(cmd);
- if (rbuf) {
- memcpy(rbuf, buf, min(offset, cmd->data_length));
- transport_kunmap_data_sg(cmd);
+ if (page == 0x3f) {
+ if (subpage != 0x00 && subpage != 0xff) {
+ cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
+ length = -EINVAL;
+ goto out;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(modesense_handlers); ++i) {
+ /*
+ * Tricky way to say all subpage 00h for
+ * subpage==0, all subpages for subpage==0xff
+ * (and we just checked above that those are
+ * the only two possibilities).
+ */
+ if ((modesense_handlers[i].subpage & ~subpage) == 0) {
+ ret = modesense_handlers[i].emulate(dev, pc, &buf[length]);
+ if (!ten && length + ret >= 255)
+ break;
+ length += ret;
+ }
+ }
+
+ goto set_length;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(modesense_handlers); ++i)
+ if (modesense_handlers[i].page == page &&
+ modesense_handlers[i].subpage == subpage) {
+ length += modesense_handlers[i].emulate(dev, pc, &buf[length]);
+ goto set_length;
+ }
+
+ /*
+ * We don't intend to implement:
+ * - obsolete page 03h "format parameters" (checked by Solaris)
+ */
+ if (page != 0x03)
+ pr_err("MODE SENSE: unimplemented page/subpage: 0x%02x/0x%02x\n",
+ page, subpage);
+
+ cmd->scsi_sense_reason = TCM_UNKNOWN_MODE_PAGE;
+ return -EINVAL;
+
+set_length:
+ if (ten)
+ put_unaligned_be16(length - 2, buf);
+ else
+ buf[0] = length - 1;
+
+out:
+ if (buf != map_buf) {
+ memcpy(map_buf, buf, cmd->data_length);
+ kfree(buf);
}
+ transport_kunmap_data_sg(cmd);
target_complete_cmd(cmd, GOOD);
return 0;
}
--
1.7.10.4
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