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Commit 3833aeaf authored by Sami Tolvanen's avatar Sami Tolvanen Committed by Gerrit - the friendly Code Review server
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ANDROID: dm verity fec: add sysfs attribute fec/corrected 



Add a sysfs entry that allows user space to determine whether dm-verity
has come across correctable errors on the underlying block device.

Bug: 22655252
Bug: 27928374
Signed-off-by: default avatarSami Tolvanen <samitolvanen@google.com>
(cherry picked from commit 7911fad5f0a2cf5afc2215657219a21e6630e001)

Change-Id: I02d36bed1d54eaf1f1750a919fa91f66a7e9b96c
Git-commit: 9cd83628
Git-repo: https://git.linaro.org/kernel/linux-linaro-stable.git


Signed-off-by: default avatarImran Khan <kimran@codeaurora.org>
parent 1a6b1e3e

drivers/md/dm-verity-fec.c

+44 −1
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 


#include "dm-verity-fec.h"

#include <linux/math64.h>

#include <linux/sysfs.h>



#define DM_MSG_PREFIX	"verity-fec"
@@ -175,9 +176,11 @@ error: 
	if (r < 0 && neras)

		DMERR_LIMIT("%s: FEC %llu: failed to correct: %d",

			    v->data_dev->name, (unsigned long long)rsb, r);

	else if (r > 0)

	else if (r > 0) {

		DMWARN_LIMIT("%s: FEC %llu: corrected %d errors",

			     v->data_dev->name, (unsigned long long)rsb, r);

		atomic_add_unless(&v->fec->corrected, 1, INT_MAX);

	}



	return r;

}
@@ -548,6 +551,7 @@ unsigned verity_fec_status_table(struct dm_verity *v, unsigned sz, 
void verity_fec_dtr(struct dm_verity *v)

{

	struct dm_verity_fec *f = v->fec;

	struct kobject *kobj = &f->kobj_holder.kobj;



	if (!verity_fec_is_enabled(v))

		goto out;
@@ -564,6 +568,12 @@ void verity_fec_dtr(struct dm_verity *v) 


	if (f->dev)

		dm_put_device(v->ti, f->dev);



	if (kobj->state_initialized) {

		kobject_put(kobj);

		wait_for_completion(dm_get_completion_from_kobject(kobj));

	}



out:

	kfree(f);

	v->fec = NULL;
@@ -652,6 +662,27 @@ int verity_fec_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v, 
	return 0;

}



static ssize_t corrected_show(struct kobject *kobj, struct kobj_attribute *attr,

			      char *buf)

{

	struct dm_verity_fec *f = container_of(kobj, struct dm_verity_fec,

					       kobj_holder.kobj);



	return sprintf(buf, "%d\n", atomic_read(&f->corrected));

}



static struct kobj_attribute attr_corrected = __ATTR_RO(corrected);



static struct attribute *fec_attrs[] = {

	&attr_corrected.attr,

	NULL

};



static struct kobj_type fec_ktype = {

	.sysfs_ops = &kobj_sysfs_ops,

	.default_attrs = fec_attrs

};



/*

 * Allocate dm_verity_fec for v->fec. Must be called before verity_fec_ctr.

 */
@@ -675,8 +706,10 @@ int verity_fec_ctr_alloc(struct dm_verity *v) 
 */

int verity_fec_ctr(struct dm_verity *v)

{

	int r;

	struct dm_verity_fec *f = v->fec;

	struct dm_target *ti = v->ti;

	struct mapped_device *md = dm_table_get_md(ti->table);

	u64 hash_blocks;



	if (!verity_fec_is_enabled(v)) {
@@ -684,6 +717,16 @@ int verity_fec_ctr(struct dm_verity *v) 
		return 0;

	}



	/* Create a kobject and sysfs attributes */

	init_completion(&f->kobj_holder.completion);



	r = kobject_init_and_add(&f->kobj_holder.kobj, &fec_ktype,

				 &disk_to_dev(dm_disk(md))->kobj, "%s", "fec");

	if (r) {

		ti->error = "Cannot create kobject";

		return r;

	}



	/*

	 * FEC is computed over data blocks, possible metadata, and

	 * hash blocks. In other words, FEC covers total of fec_blocks

drivers/md/dm-verity-fec.h

+3 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#ifndef DM_VERITY_FEC_H

#define DM_VERITY_FEC_H



#include "dm.h"

#include "dm-verity.h"

#include <linux/rslib.h>
@@ -48,6 +49,8 @@ struct dm_verity_fec { 
	mempool_t *extra_pool;	/* mempool for extra buffers */

	mempool_t *output_pool;	/* mempool for output */

	struct kmem_cache *cache;	/* cache for buffers */

	atomic_t corrected;		/* corrected errors */

	struct dm_kobject_holder kobj_holder;	/* for sysfs attributes */

};



/* per-bio data */