tcm: make pi data verification configurable

Currently ramdisk and fileio always perform PI verification
before and after backend IO. This approach is not very flexible.
Because some one may want to postpone this work to other layers in
IO stack. For example if we want to test blk_integrity_profile

testcase:
https://github.com/dmonakhov/xfstests/commit/dee408c868861d6b6871dbb3381facee7effdbe4Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/target_core_configfs.c

@@ -533,6 +533,7 @@ DEF_CONFIGFS_ATTRIB_SHOW(emulate_3pc);
 DEF_CONFIGFS_ATTRIB_SHOW(pi_prot_type);
 DEF_CONFIGFS_ATTRIB_SHOW(hw_pi_prot_type);
 DEF_CONFIGFS_ATTRIB_SHOW(pi_prot_format);
+DEF_CONFIGFS_ATTRIB_SHOW(pi_prot_verify);
 DEF_CONFIGFS_ATTRIB_SHOW(enforce_pr_isids);
 DEF_CONFIGFS_ATTRIB_SHOW(is_nonrot);
 DEF_CONFIGFS_ATTRIB_SHOW(emulate_rest_reord);
@@ -823,6 +824,7 @@ static ssize_t pi_prot_type_store(struct config_item *item,
 		ret = dev->transport->init_prot(dev);
 		if (ret) {
 			da->pi_prot_type = old_prot;
+			da->pi_prot_verify = (bool) da->pi_prot_type;
 			return ret;
 		}
 
@@ -830,6 +832,7 @@ static ssize_t pi_prot_type_store(struct config_item *item,
 		dev->transport->free_prot(dev);
 	}
 
+	da->pi_prot_verify = (bool) da->pi_prot_type;
 	pr_debug("dev[%p]: SE Device Protection Type: %d\n", dev, flag);
 	return count;
 }
@@ -872,6 +875,35 @@ static ssize_t pi_prot_format_store(struct config_item *item,
 	return count;
 }
 
+static ssize_t pi_prot_verify_store(struct config_item *item,
+		const char *page, size_t count)
+{
+	struct se_dev_attrib *da = to_attrib(item);
+	bool flag;
+	int ret;
+
+	ret = strtobool(page, &flag);
+	if (ret < 0)
+		return ret;
+
+	if (!flag) {
+		da->pi_prot_verify = flag;
+		return count;
+	}
+	if (da->hw_pi_prot_type) {
+		pr_warn("DIF protection enabled on underlying hardware,"
+			" ignoring\n");
+		return count;
+	}
+	if (!da->pi_prot_type) {
+		pr_warn("DIF protection not supported by backend, ignoring\n");
+		return count;
+	}
+	da->pi_prot_verify = flag;
+
+	return count;
+}
+
 static ssize_t force_pr_aptpl_store(struct config_item *item,
 		const char *page, size_t count)
 {
@@ -1067,6 +1099,7 @@ CONFIGFS_ATTR(, emulate_3pc);
 CONFIGFS_ATTR(, pi_prot_type);
 CONFIGFS_ATTR_RO(, hw_pi_prot_type);
 CONFIGFS_ATTR(, pi_prot_format);
+CONFIGFS_ATTR(, pi_prot_verify);
 CONFIGFS_ATTR(, enforce_pr_isids);
 CONFIGFS_ATTR(, is_nonrot);
 CONFIGFS_ATTR(, emulate_rest_reord);
@@ -1104,6 +1137,7 @@ struct configfs_attribute *sbc_attrib_attrs[] = {
 	&attr_pi_prot_type,
 	&attr_hw_pi_prot_type,
 	&attr_pi_prot_format,
+	&attr_pi_prot_verify,
 	&attr_enforce_pr_isids,
 	&attr_is_nonrot,
 	&attr_emulate_rest_reord,

drivers/target/target_core_file.c

@@ -554,7 +554,8 @@ fd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
 		ret = fd_do_rw(cmd, file, dev->dev_attrib.block_size,
 			       sgl, sgl_nents, cmd->data_length, 0);
 
-		if (ret > 0 && cmd->prot_type && dev->dev_attrib.pi_prot_type) {
+		if (ret > 0 && cmd->prot_type && dev->dev_attrib.pi_prot_type &&
+		    dev->dev_attrib.pi_prot_verify) {
 			u32 sectors = cmd->data_length >>
 					ilog2(dev->dev_attrib.block_size);
 
@@ -564,7 +565,8 @@ fd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
 				return rc;
 		}
 	} else {
-		if (cmd->prot_type && dev->dev_attrib.pi_prot_type) {
+		if (cmd->prot_type && dev->dev_attrib.pi_prot_type &&
+		    dev->dev_attrib.pi_prot_verify) {
 			u32 sectors = cmd->data_length >>
 					ilog2(dev->dev_attrib.block_size);
 

drivers/target/target_core_rd.c

@@ -410,7 +410,7 @@ static sense_reason_t rd_do_prot_rw(struct se_cmd *cmd, bool is_read)
 	u32 prot_offset, prot_page;
 	u32 prot_npages __maybe_unused;
 	u64 tmp;
-	sense_reason_t rc = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+	sense_reason_t rc = 0;
 
 	tmp = cmd->t_task_lba * se_dev->prot_length;
 	prot_offset = do_div(tmp, PAGE_SIZE);
@@ -423,13 +423,14 @@ static sense_reason_t rd_do_prot_rw(struct se_cmd *cmd, bool is_read)
 	prot_sg = &prot_table->sg_table[prot_page -
 					prot_table->page_start_offset];
 
+	if (se_dev->dev_attrib.pi_prot_verify) {
 		if (is_read)
 			rc = sbc_dif_verify(cmd, cmd->t_task_lba, sectors, 0,
 					    prot_sg, prot_offset);
 		else
 			rc = sbc_dif_verify(cmd, cmd->t_task_lba, sectors, 0,
 					    cmd->t_prot_sg, 0);
-
+	}
 	if (!rc)
 		sbc_dif_copy_prot(cmd, sectors, is_read, prot_sg, prot_offset);
 

include/target/target_core_base.h

@@ -664,6 +664,7 @@ struct se_dev_attrib {
 	int		pi_prot_format;
 	enum target_prot_type pi_prot_type;
 	enum target_prot_type hw_pi_prot_type;
+	int		pi_prot_verify;
 	int		enforce_pr_isids;
 	int		force_pr_aptpl;
 	int		is_nonrot;