0006-block-add-no_part_scan-module-parameter.patch

From a4b4ac197ecfb96377e06dc8a0fbb9d5c3867e77 Mon Sep 17 00:00:00 2001
From: Rusty Bird <rustybird@openmailbox.org>
Date: Mon, 11 Jul 2016 13:05:38 +0000
Subject: [PATCH] block: add no_part_scan module parameter

Define a boolean module parameter named "no_part_scan" defaulting to N,
which, if set to Y, always causes the GENHD_FL_NO_PART_SCAN flag to be
added to subsequently created block devices, thereby disabling the
kernel's various partition table parsers for them.

The parameter's current value can be changed at any time by writing to
the /sys/module/block/parameters/no_part_scan file.
---
 block/genhd.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/block/genhd.c b/block/genhd.c
index 8171a6bc3210f..755652ad806a9 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -424,6 +424,14 @@ static void add_disk_final(struct gendisk *disk)
 	set_bit(GD_ADDED, &disk->state);
 }
 
+#undef MODULE_PARAM_PREFIX
+#define MODULE_PARAM_PREFIX     "block."
+
+/* partition scanning policy */
+static bool disk_no_part_scan = 0;
+module_param_named(no_part_scan, disk_no_part_scan, bool, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(no_part_scan, "When adding block devices, always mark them as not to be scanned for partitions");
+
 static int __add_disk(struct device *parent, struct gendisk *disk,
 		      const struct attribute_group **groups,
 		      struct fwnode_handle *fwnode)
@@ -447,6 +455,9 @@ static int __add_disk(struct device *parent, struct gendisk *disk,
 		bdev_set_flag(disk->part0, BD_HAS_SUBMIT_BIO);
 	}
 
+	if (disk_no_part_scan)
+		disk->flags |= GENHD_FL_NO_PART;
+
 	/*
 	 * If the driver provides an explicit major number it also must provide
 	 * the number of minors numbers supported, and those will be used to
-- 
2.49.0