[PATCH 1/2] tcm: Add WRITE_SAME_16 emulation and passthrough support
From: Nicholas A. Bellinger
Date: Sat Oct 02 2010 - 20:53:51 EST
From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
This patch adds WRITE_SAME_16 emulation support into TCM Core which
is used in a followup patch by TCM/IBLOCK and TCM/FILEIO subsystems plugins
together with generic Block layer Discard logic. It also allows for existing
TCM/pSCSI passthrough support to function with the same WRITE_SAME_16 ops in
transport_generic_cmd_sequencer().
Note that WRITE_SAME_16 is setup as a TGCS_DATA_SG_IO_CDB operation, but
for the current emulated WRITE_SAME_16 w/ UNMAP=1 code we set T_TASK(cmd)->t_tasks_unmap=1
to signal IBLOCK and FILEIO that they will be callling the new transport_generic_write_same()
code, but not actually writing the WRITE_SAME_16 w/ UNMAP=1 data payload. The main
transport_generic_write_same() caller uses received LBA and Number of blocks (range)
together with blk_issue_discard() to perform the emulation.
This patch also adds a new configfs attrib fot WRITE_SAME_16 support in:
sys/kernel/config/target/core/$HBA/$DEV/attrib/emulate_tpws
by default this is disabled and will be enabled by IBLOCK+FILEIO on a struct se_device
context when blk_queue_discard()==1 is detected.
This patch also updates INQUIRY Block Limits VPD, Thin Provisioning VPD
READ_CAPACITY_* to take into account the DEV_ATTRIB(dev)->emulate_tpws=1
Here is how it looks in action with TCM_Loop -> TCM/FILEIO -> scsi_debug:
sg_vpd --page=0xb2 /dev/sdh
Thin provisioning VPD page (SBC):
Unmap supported (TPU): 1
Write same with unmap supported (TPWS): 1
Anchored LBAs not supported
Threshold exponent: 0
Descriptor present (DP): 0
sg_write_same --xferlen=4096 -S -U -v -v --lba=1024 --num=8 /dev/sdh
open /dev/sdh with flags=0x802
Default data-out buffer to 4096 zeroes
Write same(16) cmd: 93 08 00 00 00 00 00 00 04 00 00 00 00 08 00 00
Data-out buffer length=4096
Note that this has also been briefly tested with TCM_Loop -> TCM/IBLOCK ->
scsi_debug with emulate_tpws=1, as well as with WRITE_SAME_16 passthrough
with TCM_Loop -> TCM/pSCSI -> scsi_debug.
Many, many thanks to Martin Petersen for his help in this area!
Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx>
---
drivers/target/target_core_configfs.c | 4 +
drivers/target/target_core_device.c | 15 +++++-
drivers/target/target_core_transport.c | 99 ++++++++++++++++++++++++++++++--
include/target/target_core_base.h | 5 +-
include/target/target_core_device.h | 1 +
include/target/target_core_transport.h | 6 ++
6 files changed, 123 insertions(+), 7 deletions(-)
diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index ae4a894..49547ab 100644
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -566,6 +566,9 @@ SE_DEV_ATTR(emulate_tas, S_IRUGO | S_IWUSR);
DEF_DEV_ATTRIB(emulate_tpu);
SE_DEV_ATTR(emulate_tpu, S_IRUGO | S_IWUSR);
+DEF_DEV_ATTRIB(emulate_tpws);
+SE_DEV_ATTR(emulate_tpws, S_IRUGO | S_IWUSR);
+
DEF_DEV_ATTRIB(enforce_pr_isids);
SE_DEV_ATTR(enforce_pr_isids, S_IRUGO | S_IWUSR);
@@ -615,6 +618,7 @@ static struct configfs_attribute *target_core_dev_attrib_attrs[] = {
&target_core_dev_attrib_emulate_ua_intlck_ctrl.attr,
&target_core_dev_attrib_emulate_tas.attr,
&target_core_dev_attrib_emulate_tpu.attr,
+ &target_core_dev_attrib_emulate_tpws.attr,
&target_core_dev_attrib_enforce_pr_isids.attr,
&target_core_dev_attrib_hw_block_size.attr,
&target_core_dev_attrib_block_size.attr,
diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 6101382..070da98 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -1004,6 +1004,7 @@ void se_dev_set_default_attribs(struct se_device *dev)
DEV_ATTRIB(dev)->emulate_ua_intlck_ctrl = DA_EMULATE_UA_INTLLCK_CTRL;
DEV_ATTRIB(dev)->emulate_tas = DA_EMULATE_TAS;
DEV_ATTRIB(dev)->emulate_tpu = DA_EMULATE_TPU;
+ DEV_ATTRIB(dev)->emulate_tpws = DA_EMULATE_TPWS;
DEV_ATTRIB(dev)->emulate_reservations = DA_EMULATE_RESERVATIONS;
DEV_ATTRIB(dev)->emulate_alua = DA_EMULATE_ALUA;
DEV_ATTRIB(dev)->enforce_pr_isids = DA_ENFORCE_PR_ISIDS;
@@ -1231,7 +1232,19 @@ int se_dev_set_emulate_tpu(struct se_device *dev, int flag)
return -1;
}
DEV_ATTRIB(dev)->emulate_tpu = flag;
- printk(KERN_INFO "dev[%p]: SE Device Thin Provising UNMAP bit: %d\n",
+ printk(KERN_INFO "dev[%p]: SE Device Thin Provisioning UNMAP bit: %d\n",
+ dev, flag);
+ return 0;
+}
+
+int se_dev_set_emulate_tpws(struct se_device *dev, int flag)
+{
+ if ((flag != 0) && (flag != 1)) {
+ printk(KERN_ERR "Illegal value %d\n", flag);
+ return -1;
+ }
+ DEV_ATTRIB(dev)->emulate_tpws = flag;
+ printk(KERN_INFO "dev[%p]: SE Device Thin Provisioning WRITE_SAME: %d\n",
dev, flag);
return 0;
}
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 866b0fa..c320395 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -4932,9 +4932,11 @@ set_len:
case 0xb0: /* Block Limits VPD page */
/*
* Following sbc3r22 section 6.5.3 Block Limits VPD page,
- * when emulate_tpu=1 we will be expect a different page length
+ * when emulate_tpu=1 or emulate_tpws=1 we will be expect
+ * a different page length for Thin Provisioning.
*/
- if (!(DEV_ATTRIB(dev)->emulate_tpu)) {
+ if (!(DEV_ATTRIB(dev)->emulate_tpu) &&
+ !(DEV_ATTRIB(dev)->emulate_tpws)) {
if (cmd->data_length < (0x10 + 4)) {
printk(KERN_INFO "Received data_length: %u"
" too small for TPE=1 EVPD 0xb0\n",
@@ -5037,6 +5039,14 @@ set_len:
*/
if (DEV_ATTRIB(dev)->emulate_tpu != 0)
buf[5] = 0x80;
+ /*
+ * A TPWS bit set to one indicates that the device server supports
+ * the use of the WRITE SAME (16) command (see 5.42) to unmap LBAs.
+ * A TPWS bit set to zero indicates that the device server does not
+ * support the use of the WRITE SAME (16) command to unmap LBAs.
+ */
+ if (DEV_ATTRIB(dev)->emulate_tpws != 0)
+ buf[5] |= 0x40;
break;
default:
printk(KERN_ERR "Unknown VPD Code: 0x%02x\n", cdb[2]);
@@ -5065,7 +5075,7 @@ int transport_generic_emulate_readcapacity(
/*
* Set max 32-bit blocks to signal SERVICE ACTION READ_CAPACITY_16
*/
- if (DEV_ATTRIB(dev)->emulate_tpu)
+ if (DEV_ATTRIB(dev)->emulate_tpu || DEV_ATTRIB(dev)->emulate_tpws)
put_unaligned_be32(0xFFFFFFFF, &buf[0]);
return 0;
@@ -5093,9 +5103,9 @@ int transport_generic_emulate_readcapacity_16(
buf[11] = DEV_ATTRIB(dev)->block_size & 0xff;
/*
* Set Thin Provisioning Enable bit following sbc3r22 in section
- * READ CAPACITY (16) byte 14 if emulate_tpu is enabled.
+ * READ CAPACITY (16) byte 14 if emulate_tpu or emulate_tpws is enabled.
*/
- if (DEV_ATTRIB(dev)->emulate_tpu)
+ if (DEV_ATTRIB(dev)->emulate_tpu || DEV_ATTRIB(dev)->emulate_tpws)
buf[14] = 0x80;
return 0;
@@ -5534,6 +5544,38 @@ int transport_generic_unmap(struct se_cmd *cmd, struct block_device *bdev)
}
EXPORT_SYMBOL(transport_generic_unmap);
+/*
+ * Used for TCM/IBLOCK and TCM/FILEIO for block/blk-lib.c level discard support.
+ * Note this is not used for TCM/pSCSI passthrough
+ */
+int transport_generic_write_same(struct se_cmd *cmd, struct block_device *bdev)
+{
+ struct se_device *dev = SE_DEV(cmd);
+ sector_t lba;
+ unsigned int range;
+ int barrier = 0, ret;
+ /*
+ * If the UNMAP bit was not set, we should not be calling this to being with..
+ */
+ if (!(T_TASK(cmd)->t_tasks_unmap)) {
+ dump_stack();
+ return -1;
+ }
+
+ lba = T_TASK(cmd)->t_task_lba;
+ range = (cmd->data_length / TRANSPORT(dev)->get_blocksize(dev));
+
+ printk(KERN_INFO "WRITE_SAME UNMAP: LBA: %llu Range: %u\n", lba, range);
+
+ ret = blkdev_issue_discard(bdev, lba, range, GFP_KERNEL, barrier);
+ if (ret < 0) {
+ printk(KERN_INFO "blkdev_issue_discard() failed for WRITE_SAME\n");
+ return -1;
+ }
+ return 0;
+}
+EXPORT_SYMBOL(transport_generic_write_same);
+
static inline void transport_dev_get_mem_buf(
struct se_device *dev,
struct se_cmd *cmd)
@@ -6154,6 +6196,53 @@ static int transport_generic_cmd_sequencer(
ret = TGCS_CONTROL_NONSG_IO_CDB;
break;
+ case WRITE_SAME_16:
+ SET_GENERIC_TRANSPORT_FUNCTIONS(cmd);
+ cmd->transport_allocate_resources =
+ &transport_generic_allocate_buf;
+ sectors = transport_get_sectors_16(cdb, cmd, §or_ret);
+ if (sector_ret)
+ return TGCS_UNSUPPORTED_CDB;
+ size = transport_get_size(sectors, cdb, cmd);
+ transport_dev_get_mem_SG(cmd->se_orig_obj_ptr, cmd);
+ transport_get_maps(cmd);
+ cmd->transport_split_cdb = &split_cdb_XX_16;
+ cmd->transport_get_long_lba = &transport_lba_64;
+ passthrough = (TRANSPORT(dev)->transport_type ==
+ TRANSPORT_PLUGIN_PHBA_PDEV);
+ /*
+ * Determine if the received WRITE_SAME_16 is used to for direct
+ * passthrough into Linux/SCSI with struct request via TCM/pSCSI
+ * or we are signaling the use of internal WRITE_SAME + UNMAP=1
+ * emulation for -> Linux/BLOCK disbard with TCM/IBLOCK and
+ * TCM/FILEIO subsystem plugin backstores.
+ */
+ if (!(passthrough)) {
+ if ((cdb[1] & 0x04) || (cdb[1] & 0x02)) {
+ printk(KERN_ERR "WRITE_SAME PBDATA and LBDATA"
+ " bits not supported for Block Discard"
+ " Emulation\n");
+ return TGCS_INVALID_CDB_FIELD;
+ }
+ /*
+ * Currently for the emulated case we only accept
+ * tpws with the UNMAP=1 bit set.
+ */
+ if (!(cdb[1] & 0x08)) {
+ printk(KERN_ERR "WRITE_SAME w/ UNMAP bit not "
+ " supported for Block Discard Emulation\n");
+ return TGCS_INVALID_CDB_FIELD;
+ }
+
+ cmd->se_cmd_flags |= SCF_EMULATE_SYNC_WRITE_SAME;
+ /*
+ * Signal to TCM IBLOCK+FILEIO subsystem plugins that WRITE
+ * tasks will be translated to SCSI UNMAP -> Block Discard
+ */
+ T_TASK(cmd)->t_tasks_unmap = 1;
+ }
+ ret = TGCS_DATA_SG_IO_CDB;
+ break;
case ALLOW_MEDIUM_REMOVAL:
case GPCMD_CLOSE_TRACK:
case ERASE:
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index fc5300c..bceb794 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -138,7 +138,8 @@ enum se_cmd_flags_table {
SCF_EMULATE_SYNC_CACHE = 0x01000000,
SCF_EMULATE_CDB_ASYNC = 0x02000000,
SCF_EMULATE_SYNC_UNMAP = 0x04000000,
- SCF_ECDB_ALLOCATION = 0x08000000
+ SCF_ECDB_ALLOCATION = 0x08000000,
+ SCF_EMULATE_SYNC_WRITE_SAME = 0x10000000
};
/* struct se_device->type for known subsystem plugins */
@@ -431,6 +432,7 @@ struct se_transport_task {
int t_tasks_failed;
int t_tasks_fua;
int t_tasks_bidi:1;
+ int t_tasks_unmap:1;
u32 t_task_cdbs;
u32 t_tasks_check;
u32 t_tasks_no;
@@ -752,6 +754,7 @@ struct se_dev_attrib {
int emulate_ua_intlck_ctrl;
int emulate_tas;
int emulate_tpu;
+ int emulate_tpws;
int emulate_reservations;
int emulate_alua;
int enforce_pr_isids;
diff --git a/include/target/target_core_device.h b/include/target/target_core_device.h
index e8546f3..248d954 100644
--- a/include/target/target_core_device.h
+++ b/include/target/target_core_device.h
@@ -49,6 +49,7 @@ extern int se_dev_set_emulate_write_cache(struct se_device *, int);
extern int se_dev_set_emulate_ua_intlck_ctrl(struct se_device *, int);
extern int se_dev_set_emulate_tas(struct se_device *, int);
extern int se_dev_set_emulate_tpu(struct se_device *, int);
+extern int se_dev_set_emulate_tpws(struct se_device *, int);
extern int se_dev_set_enforce_pr_isids(struct se_device *, int);
extern int se_dev_set_queue_depth(struct se_device *, u32);
extern int se_dev_set_max_sectors(struct se_device *, u32);
diff --git a/include/target/target_core_transport.h b/include/target/target_core_transport.h
index d45063e..74a56f1 100644
--- a/include/target/target_core_transport.h
+++ b/include/target/target_core_transport.h
@@ -109,6 +109,11 @@
#define DA_EMULATE_TAS 1
/* Emulation for Thin Provisioning UNMAP using block/blk-lib.c:blkdev_issue_discard() */
#define DA_EMULATE_TPU 0
+/*
+ * Emulation for Thin Provisioning WRITE_SAME w/ UNMAP=1 bit using
+ * block/blk-lib.c:blkdev_issue_discard()
+ */
+#define DA_EMULATE_TPWS 0
/* No Emulation for PSCSI by default */
#define DA_EMULATE_RESERVATIONS 0
/* No Emulation for PSCSI by default */
@@ -235,6 +240,7 @@ extern int transport_generic_emulate_request_sense(struct se_cmd *,
unsigned char *);
extern int transport_get_sense_data(struct se_cmd *);
extern int transport_generic_unmap(struct se_cmd *, struct block_device *);
+extern int transport_generic_write_same(struct se_cmd *, struct block_device *);
extern struct se_cmd *transport_allocate_passthrough(unsigned char *, int, u32,
void *, u32, u32, void *);
extern void transport_passthrough_release(struct se_cmd *);
--
1.5.6.5
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/