[SCSI] scsi_debug: Add "removable" parameter

Add "removable" module parameter to set the "removable" attribute of any
subsequently created debug block device. It is a writable driver option, so
that you can switch between removable and "fixed" media block devices in
between the add_host calls.

This is useful for being able to test the different behaviour/required
privileges in e. g. the udisks test suite.
Signed-off-by: Martin Pitt <martin.pitt@ubuntu.com>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/scsi_debug.c

@@ -109,6 +109,7 @@ static const char * scsi_debug_version_date = "20100324";
 #define DEF_OPT_BLKS 64
 #define DEF_PHYSBLK_EXP 0
 #define DEF_PTYPE   0
+#define DEF_REMOVABLE false
 #define DEF_SCSI_LEVEL   5    /* INQUIRY, byte2 [5->SPC-3] */
 #define DEF_SECTOR_SIZE 512
 #define DEF_UNMAP_ALIGNMENT 0
@@ -193,11 +194,11 @@ static unsigned int scsi_debug_unmap_granularity = DEF_UNMAP_GRANULARITY;
 static unsigned int scsi_debug_unmap_max_blocks = DEF_UNMAP_MAX_BLOCKS;
 static unsigned int scsi_debug_unmap_max_desc = DEF_UNMAP_MAX_DESC;
 static unsigned int scsi_debug_write_same_length = DEF_WRITESAME_LENGTH;
+static bool scsi_debug_removable = DEF_REMOVABLE;
 
 static int scsi_debug_cmnd_count = 0;
 
 #define DEV_READONLY(TGT)      (0)
-#define DEV_REMOVEABLE(TGT)    (0)
 
 static unsigned int sdebug_store_sectors;
 static sector_t sdebug_capacity;	/* in sectors */
@@ -919,7 +920,7 @@ static int resp_inquiry(struct scsi_cmnd * scp, int target,
 		return ret;
 	}
 	/* drops through here for a standard inquiry */
-	arr[1] = DEV_REMOVEABLE(target) ? 0x80 : 0;	/* Removable disk */
+	arr[1] = scsi_debug_removable ? 0x80 : 0;	/* Removable disk */
 	arr[2] = scsi_debug_scsi_level;
 	arr[3] = 2;    /* response_data_format==2 */
 	arr[4] = SDEBUG_LONG_INQ_SZ - 5;
@@ -1211,7 +1212,7 @@ static int resp_format_pg(unsigned char * p, int pcontrol, int target)
 	p[11] = sdebug_sectors_per & 0xff;
 	p[12] = (scsi_debug_sector_size >> 8) & 0xff;
 	p[13] = scsi_debug_sector_size & 0xff;
-	if (DEV_REMOVEABLE(target))
+	if (scsi_debug_removable)
 		p[20] |= 0x20; /* should agree with INQUIRY */
 	if (1 == pcontrol)
 		memset(p + 2, 0, sizeof(format_pg) - 2);
@@ -2754,6 +2755,7 @@ module_param_named(opt_blks, scsi_debug_opt_blks, int, S_IRUGO);
 module_param_named(opts, scsi_debug_opts, int, S_IRUGO | S_IWUSR);
 module_param_named(physblk_exp, scsi_debug_physblk_exp, int, S_IRUGO);
 module_param_named(ptype, scsi_debug_ptype, int, S_IRUGO | S_IWUSR);
+module_param_named(removable, scsi_debug_removable, bool, S_IRUGO | S_IWUSR);
 module_param_named(scsi_level, scsi_debug_scsi_level, int, S_IRUGO);
 module_param_named(sector_size, scsi_debug_sector_size, int, S_IRUGO);
 module_param_named(unmap_alignment, scsi_debug_unmap_alignment, int, S_IRUGO);
@@ -2796,6 +2798,7 @@ MODULE_PARM_DESC(opt_blks, "optimal transfer length in block (def=64)");
 MODULE_PARM_DESC(opts, "1->noise, 2->medium_err, 4->timeout, 8->recovered_err... (def=0)");
 MODULE_PARM_DESC(physblk_exp, "physical block exponent (def=0)");
 MODULE_PARM_DESC(ptype, "SCSI peripheral type(def=0[disk])");
+MODULE_PARM_DESC(removable, "claim to have removable media (def=0)");
 MODULE_PARM_DESC(scsi_level, "SCSI level to simulate(def=5[SPC-3])");
 MODULE_PARM_DESC(sector_size, "logical block size in bytes (def=512)");
 MODULE_PARM_DESC(unmap_alignment, "lowest aligned thin provisioning lba (def=0)");
@@ -3205,6 +3208,25 @@ static ssize_t sdebug_map_show(struct device_driver *ddp, char *buf)
 }
 DRIVER_ATTR(map, S_IRUGO, sdebug_map_show, NULL);
 
+static ssize_t sdebug_removable_show(struct device_driver *ddp,
+				     char *buf)
+{
+	return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_removable ? 1 : 0);
+}
+static ssize_t sdebug_removable_store(struct device_driver *ddp,
+				      const char *buf, size_t count)
+{
+	int n;
+
+	if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
+		scsi_debug_removable = (n > 0);
+		return count;
+	}
+	return -EINVAL;
+}
+DRIVER_ATTR(removable, S_IRUGO | S_IWUSR, sdebug_removable_show,
+	    sdebug_removable_store);
+
 
 /* Note: The following function creates attribute files in the
    /sys/bus/pseudo/drivers/scsi_debug directory. The advantage of these
@@ -3230,6 +3252,7 @@ static int do_create_driverfs_files(void)
 	ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_num_tgts);
 	ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_ptype);
 	ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_opts);
+	ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_removable);
 	ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_scsi_level);
 	ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_virtual_gb);
 	ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_vpd_use_hostno);
@@ -3255,6 +3278,7 @@ static void do_remove_driverfs_files(void)
 	driver_remove_file(&sdebug_driverfs_driver, &driver_attr_scsi_level);
 	driver_remove_file(&sdebug_driverfs_driver, &driver_attr_opts);
 	driver_remove_file(&sdebug_driverfs_driver, &driver_attr_ptype);
+	driver_remove_file(&sdebug_driverfs_driver, &driver_attr_removable);
 	driver_remove_file(&sdebug_driverfs_driver, &driver_attr_num_tgts);
 	driver_remove_file(&sdebug_driverfs_driver, &driver_attr_num_parts);
 	driver_remove_file(&sdebug_driverfs_driver, &driver_attr_no_uld);