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Commit ab45e763 authored by Vishal Verma's avatar Vishal Verma Committed by Dan Williams
Browse files

libnvdimm, btt: consolidate arena validation 



Use arena_is_valid as a common routine for checking the validity of an
info block from both discover_arenas, and nd_btt_probe.

As a result, don't check for validity of the BTT's UUID, and lbasize.
The checksum in the BTT info block guarantees self-consistency, and when
we're called from nd_btt_probe, we don't have a valid uuid or lbasize
available to check against.

Also cleanup to return a bool instead of an int.

Signed-off-by: default avatarVishal Verma <vishal.l.verma@intel.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent fbde1414

drivers/nvdimm/btt.c

+1 −27
Original line number Diff line number Diff line
@@ -582,32 +582,6 @@ static void free_arenas(struct btt *btt) 
	}

}



/*

 * This function checks if the metadata layout is valid and error free

 */

static int arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super)

{

	u64 checksum;



	if (memcmp(super->uuid, nd_btt->uuid, 16))

		return 0;



	checksum = le64_to_cpu(super->checksum);

	super->checksum = 0;

	if (checksum != nd_btt_sb_checksum(super))

		return 0;

	super->checksum = cpu_to_le64(checksum);



	if (nd_btt->lbasize != le32_to_cpu(super->external_lbasize))

		return 0;



	/* TODO: figure out action for this */

	if ((le32_to_cpu(super->flags) & IB_FLAG_ERROR_MASK) != 0)

		dev_info(&nd_btt->dev, "Found arena with an error flag\n");



	return 1;

}



/*

 * This function reads an existing valid btt superblock and

 * populates the corresponding arena_info struct
@@ -665,7 +639,7 @@ static int discover_arenas(struct btt *btt) 
		if (ret)

			goto out;



		if (!arena_is_valid(btt->nd_btt, super)) {

		if (!nd_btt_arena_is_valid(btt->nd_btt, super)) {

			if (remaining == btt->rawsize) {

				btt->init_state = INIT_NOTFOUND;

				dev_info(to_dev(arena), "No existing arenas\n");

drivers/nvdimm/btt.h

+3 −0
Original line number Diff line number Diff line
@@ -182,4 +182,7 @@ struct btt { 
	int init_state;

	int num_arenas;

};



bool nd_btt_arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super);



#endif

drivers/nvdimm/btt_devs.c

+33 −9
Original line number Diff line number Diff line
@@ -342,6 +342,38 @@ struct device *nd_btt_create(struct nd_region *nd_region) 
	return dev;

}



/**

 * nd_btt_arena_is_valid - check if the metadata layout is valid

 * @nd_btt:	device with BTT geometry and backing device info

 * @super:	pointer to the arena's info block being tested

 *

 * Check consistency of the btt info block with itself by validating

 * the checksum.

 *

 * Returns:

 * false for an invalid info block, true for a valid one

 */

bool nd_btt_arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super)

{

	u64 checksum;



	if (memcmp(super->signature, BTT_SIG, BTT_SIG_LEN) != 0)

		return false;



	checksum = le64_to_cpu(super->checksum);

	super->checksum = 0;

	if (checksum != nd_btt_sb_checksum(super))

		return false;

	super->checksum = cpu_to_le64(checksum);



	/* TODO: figure out action for this */

	if ((le32_to_cpu(super->flags) & IB_FLAG_ERROR_MASK) != 0)

		dev_info(&nd_btt->dev, "Found arena with an error flag\n");



	return true;

}

EXPORT_SYMBOL(nd_btt_arena_is_valid);



/*

 * nd_btt_sb_checksum: compute checksum for btt info block

 *
@@ -364,8 +396,6 @@ EXPORT_SYMBOL(nd_btt_sb_checksum); 
static int __nd_btt_probe(struct nd_btt *nd_btt,

		struct nd_namespace_common *ndns, struct btt_sb *btt_sb)

{

	u64 checksum;



	if (!btt_sb || !ndns || !nd_btt)

		return -ENODEV;
@@ -375,14 +405,8 @@ static int __nd_btt_probe(struct nd_btt *nd_btt, 
	if (nvdimm_namespace_capacity(ndns) < SZ_16M)

		return -ENXIO;



	if (memcmp(btt_sb->signature, BTT_SIG, BTT_SIG_LEN) != 0)

		return -ENODEV;



	checksum = le64_to_cpu(btt_sb->checksum);

	btt_sb->checksum = 0;

	if (checksum != nd_btt_sb_checksum(btt_sb))

	if (!nd_btt_arena_is_valid(nd_btt, btt_sb))

		return -ENODEV;

	btt_sb->checksum = cpu_to_le64(checksum);



	nd_btt->lbasize = le32_to_cpu(btt_sb->external_lbasize);

	nd_btt->uuid = kmemdup(btt_sb->uuid, 16, GFP_KERNEL);