In _badblocks_check(), there are lines of code like this,
1246 sectors -= len;
[snipped]
1251 WARN_ON(sectors < 0);
The WARN_ON() at line 1257 doesn't make sense because sectors is
unsigned long long type and never to be <0.
Fix it by checking directly checking whether sectors is less than len.
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Coly Li <colyli@kernel.org>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20250309160556.42854-1-colyli@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There is a truncation of badblocks length issue when set badblocks as
follow:
echo "2055 4294967299" > bad_blocks
cat bad_blocks
2055 3
Change 'sectors' argument type from 'int' to 'sector_t'.
This change avoids truncation of badblocks length for large sectors by
replacing 'int' with 'sector_t' (u64), enabling proper handling of larger
disk sizes and ensuring compatibility with 64-bit sector addressing.
Fixes: 9e0e252a048b ("badblocks: Add core badblock management code")
Signed-off-by: Zheng Qixing <zhengqixing@huawei.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Coly Li <colyli@kernel.org>
Link: https://lore.kernel.org/r/20250227075507.151331-13-zhengqixing@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Change the return type of badblocks_set() and badblocks_clear()
from int to bool, indicating success or failure. Specifically:
- _badblocks_set() and _badblocks_clear() functions now return
true for success and false for failure.
- All calls to these functions are updated to handle the new
boolean return type.
- This change improves code clarity and ensures a more consistent
handling of success and failure states.
Signed-off-by: Zheng Qixing <zhengqixing@huawei.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Coly Li <colyli@kernel.org>
Acked-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20250227075507.151331-11-zhengqixing@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The bad blocks check would miss bad blocks when retrying under contention,
as checking parameters are not reset. These stale values from the previous
attempt could lead to incorrect scanning in the subsequent retry.
Move seqlock to outer function and reinitialize checking state for each
retry. This ensures a clean state for each check attempt, preventing any
missed bad blocks.
Fixes: 3ea3354cb9f0 ("badblocks: improve badblocks_check() for multiple ranges handling")
Signed-off-by: Zheng Qixing <zhengqixing@huawei.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Coly Li <colyli@kernel.org>
Link: https://lore.kernel.org/r/20250227075507.151331-10-zhengqixing@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There is a merge issue when adding badblocks as follow:
echo 0 10 > bad_blocks
echo 30 10 > bad_blocks
echo 20 10 > bad_blocks
cat bad_blocks
0 10
20 10 //should be merged with (30 10)
30 10
In this case, if new badblocks does not intersect with prev, it is added
by insert_at(). If there is an intersection with prev+1, the merge will
be processed in the next re_insert loop.
However, when the end of the new badblocks is exactly equal to the offset
of prev+1, no further re_insert loop occurs, and the two badblocks are not
merge.
Fix it by inc prev, badblocks can be merged during the subsequent code.
Fixes: aa511ff8218b ("badblocks: switch to the improved badblock handling code")
Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20250227075507.151331-9-zhengqixing@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Regardless of whether overlap_front() returns true or false,
can_merge_front() will be executed first. Therefore, move
can_merge_front() in front of can_merge_front() to simplify code.
Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20250227075507.151331-8-zhengqixing@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The number of badblocks cannot exceed MAX_BADBLOCKS, but it should be
allowed to equal MAX_BADBLOCKS.
Fixes: aa511ff8218b ("badblocks: switch to the improved badblock handling code")
Fixes: c3c6a86e9efc ("badblocks: add helper routines for badblock ranges handling")
Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Zhu Yanjun <yanjun.zhu@linux.dev>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Coly Li <colyli@kernel.org>
Link: https://lore.kernel.org/r/20250227075507.151331-7-zhengqixing@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
_badblocks_set() returns success if at least one badblock is set
successfully, even if others fail. This can lead to data inconsistencies
in raid, where a failed badblock set should trigger the disk to be kicked
out to prevent future reads from failed write areas.
_badblocks_set() should return error if any badblock set fails. Instead
of relying on 'rv', directly returning 'sectors' for clearer logic. If all
badblocks are successfully set, 'sectors' will be 0, otherwise it
indicates the number of badblocks that have not been set yet, thus
signaling failure.
By the way, it can also fix an issue: when a newly set unack badblock is
included in an existing ack badblock, the setting will return an error.
···
echo "0 100" /sys/block/md0/md/dev-loop1/bad_blocks
echo "0 100" /sys/block/md0/md/dev-loop1/unacknowledged_bad_blocks
-bash: echo: write error: No space left on device
```
After fix, it will return success.
Fixes: aa511ff8218b ("badblocks: switch to the improved badblock handling code")
Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Coly Li <colyli@kernel.org>
Link: https://lore.kernel.org/r/20250227075507.151331-6-zhengqixing@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In the current handling of badblocks settings, a lot of processing has
been done for scenarios where the number of badblocks exceeds 512.
This makes the code look quite complex and also introduces some issues,
For example, if there is 512 badblocks already:
for((i=0; i<510; i++)); do ((sector=i*2)); echo "$sector 1" > bad_blocks; done
echo 2100 10 > bad_blocks
echo 2200 10 > bad_blocks
Set new one, exceed 512:
echo 2000 500 > bad_blocks
Expected:
2000 500
Actual:
2100 400
In fact, a disk shouldn't have too many badblocks, and for disks with
512 badblocks, attempting to set more bad blocks doesn't make much sense.
At that point, the more appropriate action would be to replace the disk.
Therefore, to resolve these issues and simplify the code somewhat, return
error directly when setting badblocks exceeds 512.
Fixes: aa511ff8218b ("badblocks: switch to the improved badblock handling code")
Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20250227075507.151331-5-zhengqixing@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If ack and unack badblocks are adjacent, they will not be merged and will
remain as two separate badblocks. Even after the bad blocks are written
to disk and both become ack, they will still remain as two independent
bad blocks. This is not ideal as it wastes the limited space for
badblocks. Therefore, during ack_all_badblocks(), attempt to merge
badblocks if they are adjacent.
Fixes: aa511ff8218b ("badblocks: switch to the improved badblock handling code")
Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Coly Li <colyli@kernel.org>
Link: https://lore.kernel.org/r/20250227075507.151331-4-zhengqixing@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
'bb->shift' is used directly in badblocks. It is wrong, fix it.
Fixes: 3ea3354cb9f0 ("badblocks: improve badblocks_check() for multiple ranges handling")
Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Coly Li <colyli@kernel.org>
Link: https://lore.kernel.org/r/20250227075507.151331-2-zhengqixing@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If prev_badblocks() returns '-1', it means no valid badblocks record
before the checking range. It doesn't make sense to check whether
the input checking range is overlapped with the non-existed invalid
front range.
This patch checkes whether 'prev >= 0' is true before calling
overlap_front(), to void such invalid operations.
Fixes: 3ea3354cb9f0 ("badblocks: improve badblocks_check() for multiple ranges handling")
Reported-and-tested-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/nvdimm/3035e75a-9be0-4bc3-8d4a-6e52c207f277@leemhuis.info/
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Geliang Tang <geliang.tang@suse.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: NeilBrown <neilb@suse.de>
Cc: Vishal L Verma <vishal.l.verma@intel.com>
Cc: Xiao Ni <xni@redhat.com>
Link: https://lore.kernel.org/r/20231224002820.20234-1-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This patch removes old code of badblocks_set(), badblocks_clear() and
badblocks_check(), and make them as wrappers to call _badblocks_set(),
_badblocks_clear() and _badblocks_check().
By this change now the badblock handing switch to the improved algorithm
in _badblocks_set(), _badblocks_clear() and _badblocks_check().
This patch only contains the changes of old code deletion, new added
code for the improved algorithms are in previous patches.
Signed-off-by: Coly Li <colyli@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Geliang Tang <geliang.tang@suse.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: NeilBrown <neilb@suse.de>
Cc: Vishal L Verma <vishal.l.verma@intel.com>
Cc: Xiao Ni <xni@redhat.com>
Reviewed-by: Xiao Ni <xni@redhat.com>
Acked-by: Geliang Tang <geliang.tang@suse.com>
Link: https://lore.kernel.org/r/20230811170513.2300-7-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This patch rewrites badblocks_check() with similar coding style as
_badblocks_set() and _badblocks_clear(). The only difference is bad
blocks checking may handle multiple ranges in bad tables now.
If a checking range covers multiple bad blocks range in bad block table,
like the following condition (C is the checking range, E1, E2, E3 are
three bad block ranges in bad block table),
+------------------------------------+
| C |
+------------------------------------+
+----+ +----+ +----+
| E1 | | E2 | | E3 |
+----+ +----+ +----+
The improved badblocks_check() algorithm will divide checking range C
into multiple parts, and handle them in 7 runs of a while-loop,
+--+ +----+ +----+ +----+ +----+ +----+ +----+
|C1| | C2 | | C3 | | C4 | | C5 | | C6 | | C7 |
+--+ +----+ +----+ +----+ +----+ +----+ +----+
+----+ +----+ +----+
| E1 | | E2 | | E3 |
+----+ +----+ +----+
And the start LBA and length of range E1 will be set as first_bad and
bad_sectors for the caller.
The return value rule is consistent for multiple ranges. For example if
there are following bad block ranges in bad block table,
Index No. Start Len Ack
0 400 20 1
1 500 50 1
2 650 20 0
the return value, first_bad, bad_sectors by calling badblocks_set() with
different checking range can be the following values,
Checking Start, Len Return Value first_bad bad_sectors
100, 100 0 N/A N/A
100, 310 1 400 10
100, 440 1 400 10
100, 540 1 400 10
100, 600 -1 400 10
100, 800 -1 400 10
In order to make code review easier, this patch names the improved bad
block range checking routine as _badblocks_check() and does not change
existing badblock_check() code yet. Later patch will delete old code of
badblocks_check() and make it as a wrapper to call _badblocks_check().
Then the new added code won't mess up with the old deleted code, it will
be more clear and easier for code review.
Signed-off-by: Coly Li <colyli@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Geliang Tang <geliang.tang@suse.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: NeilBrown <neilb@suse.de>
Cc: Vishal L Verma <vishal.l.verma@intel.com>
Cc: Xiao Ni <xni@redhat.com>
Reviewed-by: Xiao Ni <xni@redhat.com>
Acked-by: Geliang Tang <geliang.tang@suse.com>
Link: https://lore.kernel.org/r/20230811170513.2300-6-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
With the fundamental ideas and helper routines from badblocks_set()
improvement, clearing bad block for multiple ranges is much simpler.
With a similar idea from badblocks_set() improvement, this patch
simplifies bad block range clearing into 5 situations. No matter how
complicated the clearing condition is, we just look at the head part
of clearing range with relative already set bad block range from the
bad block table. The rested part will be handled in next run of the
while-loop.
Based on existing helpers added from badblocks_set(), this patch adds
two more helpers,
- front_clear()
Clear the bad block range from bad block table which is front
overlapped with the clearing range.
- front_splitting_clear()
Handle the condition that the clearing range hits middle of an
already set bad block range from bad block table.
Similar as badblocks_set(), the first part of clearing range is handled
with relative bad block range which is find by prev_badblocks(). In most
cases a valid hint is provided to prev_badblocks() to avoid unnecessary
bad block table iteration.
This patch also explains the detail algorithm code comments at beginning
of badblocks.c, including which five simplified situations are
categrized and how all the bad block range clearing conditions are
handled by these five situations.
Again, in order to make the code review easier and avoid the code
changes mixed together, this patch does not modify badblock_clear() and
implement another routine called _badblock_clear() for the improvement.
Later patch will delete current code of badblock_clear() and make it as
a wrapper to _badblock_clear(), so the code change can be much clear for
review.
Signed-off-by: Coly Li <colyli@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Geliang Tang <geliang.tang@suse.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: NeilBrown <neilb@suse.de>
Cc: Vishal L Verma <vishal.l.verma@intel.com>
Cc: Xiao Ni <xni@redhat.com>
Reviewed-by: Xiao Ni <xni@redhat.com>
Acked-by: Geliang Tang <geliang.tang@suse.com>
Link: https://lore.kernel.org/r/20230811170513.2300-5-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Recently I received a bug report that current badblocks code does not
properly handle multiple ranges. For example,
badblocks_set(bb, 32, 1, true);
badblocks_set(bb, 34, 1, true);
badblocks_set(bb, 36, 1, true);
badblocks_set(bb, 32, 12, true);
Then indeed badblocks_show() reports,
32 3
36 1
But the expected bad blocks table should be,
32 12
Obviously only the first 2 ranges are merged and badblocks_set() returns
and ignores the rest setting range.
This behavior is improper, if the caller of badblocks_set() wants to set
a range of blocks into bad blocks table, all of the blocks in the range
should be handled even the previous part encountering failure.
The desired way to set bad blocks range by badblocks_set() is,
- Set as many as blocks in the setting range into bad blocks table.
- Merge the bad blocks ranges and occupy as less as slots in the bad
blocks table.
- Fast.
Indeed the above proposal is complicated, especially with the following
restrictions,
- The setting bad blocks range can be acknowledged or not acknowledged.
- The bad blocks table size is limited.
- Memory allocation should be avoided.
The basic idea of the patch is to categorize all possible bad blocks
range setting combinations into much less simplified and more less
special conditions. Inside badblocks_set() there is an implicit loop
composed by jumping between labels 're_insert' and 'update_sectors'. No
matter how large the setting bad blocks range is, in every loop just a
minimized range from the head is handled by a pre-defined behavior from
one of the categorized conditions. The logic is simple and code flow is
manageable.
The different relative layout between the setting range and existing bad
block range are checked and handled (merge, combine, overwrite, insert)
by the helpers in previous patch. This patch is to make all the helpers
work together with the above idea.
This patch only has the algorithm improvement for badblocks_set(). There
are following patches contain improvement for badblocks_clear() and
badblocks_check(). But the algorithm in badblocks_set() is fundamental
and typical, other improvement in clear and check routines are based on
all the helpers and ideas in this patch.
In order to make the change to be more clear for code review, this patch
does not directly modify existing badblocks_set(), and just add a new
one named _badblocks_set(). Later patch will remove current existing
badblocks_set() code and make it as a wrapper of _badblocks_set(). So
the new added change won't be mixed with deleted code, the code review
can be easier.
Signed-off-by: Coly Li <colyli@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Geliang Tang <geliang.tang@suse.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: NeilBrown <neilb@suse.de>
Cc: Vishal L Verma <vishal.l.verma@intel.com>
Cc: Wols Lists <antlists@youngman.org.uk>
Cc: Xiao Ni <xni@redhat.com>
Reviewed-by: Xiao Ni <xni@redhat.com>
Acked-by: Geliang Tang <geliang.tang@suse.com>
Link: https://lore.kernel.org/r/20230811170513.2300-4-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This patch adds several helper routines to improve badblock ranges
handling. These helper routines will be used later in the improved
version of badblocks_set()/badblocks_clear()/badblocks_check().
- Helpers prev_by_hint() and prev_badblocks() are used to find the bad
range from bad table which the searching range starts at or after.
- The following helpers are to decide the relative layout between the
manipulating range and existing bad block range from bad table.
- can_merge_behind()
Return 'true' if the manipulating range can backward merge with the
bad block range.
- can_merge_front()
Return 'true' if the manipulating range can forward merge with the
bad block range.
- can_combine_front()
Return 'true' if two adjacent bad block ranges before the
manipulating range can be merged.
- overlap_front()
Return 'true' if the manipulating range exactly overlaps with the
bad block range in front of its range.
- overlap_behind()
Return 'true' if the manipulating range exactly overlaps with the
bad block range behind its range.
- can_front_overwrite()
Return 'true' if the manipulating range can forward overwrite the
bad block range in front of its range.
- The following helpers are to add the manipulating range into the bad
block table. Different routine is called with the specific relative
layout between the manipulating range and other bad block range in the
bad block table.
- behind_merge()
Merge the manipulating range with the bad block range behind its
range, and return the number of merged length in unit of sector.
- front_merge()
Merge the manipulating range with the bad block range in front of
its range, and return the number of merged length in unit of sector.
- front_combine()
Combine the two adjacent bad block ranges before the manipulating
range into a larger one.
- front_overwrite()
Overwrite partial of whole bad block range which is in front of the
manipulating range. The overwrite may split existing bad block range
and generate more bad block ranges into the bad block table.
- insert_at()
Insert the manipulating range at a specific location in the bad
block table.
All the above helpers are used in later patches to improve the bad block
ranges handling for badblocks_set()/badblocks_clear()/badblocks_check().
Signed-off-by: Coly Li <colyli@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Geliang Tang <geliang.tang@suse.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: NeilBrown <neilb@suse.de>
Cc: Vishal L Verma <vishal.l.verma@intel.com>
Cc: Xiao Ni <xni@redhat.com>
Reviewed-by: Xiao Ni <xni@redhat.com>
Acked-by: Geliang Tang <geliang.tang@suse.com>
Link: https://lore.kernel.org/r/20230811170513.2300-3-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Get rid of redundant assignments to a variable sectors from functions
badblocks_check and badblocks_clear. This variable, that is a function
parameter, is being assigned a value that is never read until the end of
function.
Reported by clang-tidy [deadcode.DeadStores]
Signed-off-by: Michal Orzel <michalorzel.eng@gmail.com>
Link: https://lore.kernel.org/r/20220423113811.13335-1-michalorzel.eng@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
All these files have some form of the usual GPLv2 boilerplate. Switch
them to use SPDX tags instead.
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
MD's rdev_set_badblocks() expects that badblocks_set() returns 1 if
badblocks are disabled, otherwise, rdev_set_badblocks() will record
superblock changes and return success in that case and md will fail to
report an IO error which it should.
This bug has existed since badblocks were introduced in commit
9e0e252a048b ("badblocks: Add core badblock management code").
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Acked-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
This patch suppresses gcc 7 warnings about falling through in switch
statements when building with W=1. From the gcc documentation: The
-Wimplicit-fallthrough=3 warning is enabled by -Wextra. See also
https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gcc/Warning-Options.html.
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When bandblocks_set acknowledges a range or badblocks_clear a range,
it's possible all badblocks are acknowledged. We should update
unacked_exist if this occurs.
Signed-off-by: Shaohua Li <shli@fb.com>
Reviewed-by: Tomasz Majchrzak <tomasz.majchrzak@intel.com>
Tested-by: Tomasz Majchrzak <tomasz.majchrzak@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Current bad block clear implementation assumes the range to clear
overlaps with at least one bad block already stored. If given range to
clear precedes first bad block in a list, the first entry is incorrectly
updated.
Check not only if stored block end is past clear block end but also if
stored block start is before clear block end.
Signed-off-by: Tomasz Majchrzak <tomasz.majchrzak@intel.com>
Acked-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Provide a devres interface for initializing a badblocks instance. The
pmem driver has several scenarios where it will be beneficial to have
this structure automatically freed when the device is disabled / fails
probe.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
The badblocks list attached to a gendisk is allocated by the driver
which equates to the driver owning the lifetime of the object. Do not
automatically free it in del_gendisk(). This is in preparation for
expanding the use of badblocks in libnvdimm drivers and introducing
devm_init_badblocks().
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
For symmetry with badblocks_init() make it clear that this path only
destroys incremental allocations of a badblocks instance, and does not
free the badblocks instance itself.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Take the core badblocks implementation from md, and make it generally
available. This follows the same style as kernel implementations of
linked lists, rb-trees etc, where you can have a structure that can be
embedded anywhere, and accessor functions to manipulate the data.
The only changes in this copy of the code are ones to generalize
function/variable names from md-specific ones. Also add init and free
functions.
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
