scsi: target: drop unused pi_prot_format attribute storage

On write, the pi_prot_format configfs attribute invokes the device
format_prot() callback if present. Read dumps the contents of
se_dev_attrib.pi_prot_format which is always zero.  Make the configfs
attribute write-only, and drop the always zero se_dev_attrib.pi_prot_format
storage.
Signed-off-by: David Disseldorp <ddiss@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/target/target_core_configfs.c

@@ -535,7 +535,6 @@ DEF_CONFIGFS_ATTRIB_SHOW(emulate_3pc);
 DEF_CONFIGFS_ATTRIB_SHOW(emulate_pr);
 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);
@@ -1121,7 +1120,7 @@ CONFIGFS_ATTR(, emulate_3pc);
 CONFIGFS_ATTR(, emulate_pr);
 CONFIGFS_ATTR(, pi_prot_type);
 CONFIGFS_ATTR_RO(, hw_pi_prot_type);
-CONFIGFS_ATTR(, pi_prot_format);
+CONFIGFS_ATTR_WO(, pi_prot_format);
 CONFIGFS_ATTR(, pi_prot_verify);
 CONFIGFS_ATTR(, enforce_pr_isids);
 CONFIGFS_ATTR(, is_nonrot);

include/target/target_core_base.h

@@ -667,7 +667,6 @@ struct se_dev_attrib {
 	int		emulate_caw;
 	int		emulate_3pc;
 	int		emulate_pr;
-	int		pi_prot_format;
 	enum target_prot_type pi_prot_type;
 	enum target_prot_type hw_pi_prot_type;
 	int		pi_prot_verify;