Get whether the two gaps to be overwritten are empty to avoid calling
mas_update_gap() all the time. Also clean up the code and add comments.
Link: https://lkml.kernel.org/r/20230524031247.65949-9-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add comment for mas_wr_append(), move mas_update_gap() into
mas_wr_append(), and other cleanups to make mas_wr_modify() cleaner.
Link: https://lkml.kernel.org/r/20230524031247.65949-8-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The previous new_end calculation is inaccurate, because it assumes that
two new pivots must be added (this is inaccurate), and sometimes it will
miss the fast path and enter the slow path. Add mas_wr_new_end() to
accurately calculate new_end to make the conditions for entering the fast
path more accurate.
Link: https://lkml.kernel.org/r/20230524031247.65949-7-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Just make the code symmetrical to improve readability.
Link: https://lkml.kernel.org/r/20230524031247.65949-6-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Make the code for detecting spanning writes more concise.
Link: https://lkml.kernel.org/r/20230524031247.65949-5-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Fix the arguments to __must_hold() to make sparse work.
Link: https://lkml.kernel.org/r/20230524031247.65949-4-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mas_{rev_}alloc() and mas_fill_gap() are no longer used, delete them.
Link: https://lkml.kernel.org/r/20230524031247.65949-3-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Clean ups for maple tree", v4.
Some clean ups, mainly to make the code of maple tree more concise.
This patchset has passed the self-test.
This patch (of 10):
Use mas_empty_area{_rev}() to refactor mtree_alloc_{range,rrange}()
Link: https://lkml.kernel.org/r/20230524031247.65949-2-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When there is a single entry tree (range of 0-0 pointing to an entry),
then ensure the limit is either 0-0 or 1-oo, depending on where the user
walks. Ensure the correct node setting as well; either MAS_ROOT or
MAS_NONE.
Link: https://lkml.kernel.org/r/20230518145544.1722059-33-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Some users of the maple tree may want to move to the previous range
regardless of the value stored there. Add this interface as well as the
'find' variant to support walking to the first value, then iterating over
the previous ranges.
Link: https://lkml.kernel.org/r/20230518145544.1722059-32-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sometimes the user needs to revert to the previous slot, regardless of if
it is empty or not. Add an interface to go to the previous slot.
Since there can't be two consecutive NULLs in the tree, the mas_prev()
function can be implemented by calling mas_prev_slot() a maximum of 2
times. Change the underlying interface to use mas_prev_slot() to align
the code.
Link: https://lkml.kernel.org/r/20230518145544.1722059-31-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
These functions need to move for future use.
Link: https://lkml.kernel.org/r/20230518145544.1722059-30-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Some users of the maple tree may want to move to the next range in the
tree, even if it stores a NULL. This family of function provides that
functionality by advancing one slot at a time and returning the result,
while mas_contiguous() will iterate over the range and stop on
encountering the first NULL.
Link: https://lkml.kernel.org/r/20230518145544.1722059-29-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sometimes, during a tree walk, the user needs the next slot regardless of
if it is empty or not. Add an interface to get the next slot.
Since there are no consecutive NULLs allowed in the tree, the mas_next()
function can only advance two slots at most. So use the new
mas_next_slot() interface to align both implementations. Use this method
for mas_find() as well.
Link: https://lkml.kernel.org/r/20230518145544.1722059-28-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Since the maple tree is inclusive in range, ensure that a range of 1 (min
= max) works for searching for a gap in either direction, and make sure
the size is at least 1 but not larger than the delta between min and max.
This commit also updates the testing. Unfortunately there isn't a way to
safely update the tests and code without a test failure.
Link: https://lkml.kernel.org/r/20230518145544.1722059-26-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Suggested-by: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Keep a reference to the node when possible with mas_prev(). This will
avoid re-walking the tree. In keeping a reference to the node, keep the
last/index accurate to the range being referenced. This means the limit
may be within the range, but the range may extend outside of the limit.
Also fix the single entry tree to respect the range (of 0), or set the
node to MAS_NONE in the case of shifting beyond 0.
Link: https://lkml.kernel.org/r/20230518145544.1722059-25-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Clean up the mas_next() call to try and keep a node reference when
possible. This will avoid re-walking the tree in most cases.
Also clean up the single entry tree handling to ensure index/last are
consistent with what one would expect. (returning NULL with limit of
1-oo).
Link: https://lkml.kernel.org/r/20230518145544.1722059-24-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When a dead node is detected, the depth has already been set to 1 so reset
it to 0.
Link: https://lkml.kernel.org/r/20230518145544.1722059-22-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mas_destroy currently checks if mas->node is MAS_START prior to calling
mas_start(), but this is unnecessary as mas_start() will do nothing if the
node is anything but MAS_START.
Link: https://lkml.kernel.org/r/20230518145544.1722059-21-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Rename mte_pivots() to mas_pivots() and pass through the ma_state to set
the error code to -EIO when the offset is out of range for the node type.
Change the WARN_ON() to MAS_WARN_ON() to log the maple state.
Link: https://lkml.kernel.org/r/20230518145544.1722059-16-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Replace the call to BUG_ON() in mas_meta_gap() with calls before the
function call MAS_BUG_ON() to get more information on error condition.
Link: https://lkml.kernel.org/r/20230518145544.1722059-15-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mas_store_prealloc() should never fail, but if it does due to internal
tree issues then get as much debug information as possible prior to
crashing the kernel.
Link: https://lkml.kernel.org/r/20230518145544.1722059-14-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In the even of trying to remove data from a leaf node by use of
mas_topiary_range(), log the maple state.
Link: https://lkml.kernel.org/r/20230518145544.1722059-13-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use MAS_BUG_ON() instead of MT_BUG_ON() to get the maple state
information. In the unlikely event of a tree height of > 31, try to
increase the probability of useful information being logged.
Link: https://lkml.kernel.org/r/20230518145544.1722059-12-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use MAS_BUG_ON() to dump the maple state and tree in the unlikely event of
an issue.
Link: https://lkml.kernel.org/r/20230518145544.1722059-11-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Using MT_WARN_ON() allows for the removal of if statements before logging.
Using MAS_WARN_ON() will provide more information when issues are
encountered.
Link: https://lkml.kernel.org/r/20230518145544.1722059-10-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use MT_BUG_ON() to get more information when running with MAPLE_TREE_DEBUG
enabled.
Link: https://lkml.kernel.org/r/20230518145544.1722059-8-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add debug macros to dump the maple state and/or the tree for both warning
and bug_on calls.
Link: https://lkml.kernel.org/r/20230518145544.1722059-7-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Allow different formatting strings to be used when dumping the tree.
Currently supports hex and decimal.
Link: https://lkml.kernel.org/r/20230518145544.1722059-6-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Convert loop type to ensure all variables are set to make the compiler
happy, and use the mas_is_none() function instead of explicitly checking
the node in the maple state.
Link: https://lkml.kernel.org/r/20230518145544.1722059-5-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The maple tree node limits are implied by the parent. When walking up the
tree, the limit may not be known until a slot that does not have implied
limits are encountered. However, if the node is the left-most or
right-most node, the walking up to find that limit can be skipped.
This commit also fixes the debug/testing code that was not setting the
limit on walking down the tree as that optimization is not compatible with
this change.
Link: https://lkml.kernel.org/r/20230518145544.1722059-4-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mas_parent_enum() is a simple wrapper for mte_parent_enum() which is only
called from that wrapper. Remove the wrapper and inline mte_parent_enum()
into mas_parent_enum().
At the same time, clean up the bit masking of the root pointer since it
cannot be set by the time the bit masking occurs. Change the check on the
root bit to a WARN_ON(), and fix the verification code to not trigger the
WARN_ON() before checking if the node is root.
Align the name to mas_parent_type() since mas_node_type() exists already.
Link: https://lkml.kernel.org/r/20230518145544.1722059-3-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Maple tree mas_{next,prev}_range() and cleanup", v4.
This patchset contains a number of clean ups to the code to make it more
usable (next/prev range), the addition of debug output formatting, the
addition of printing the maple state information in the WARN_ON/BUG_ON
code.
There is also work done here to keep nodes active during iterations to
reduce the necessity of re-walking the tree.
Finally, there is a new interface added to move to the next or previous
range in the tree, even if it is empty.
The organisation of the patches is as follows:
0001-0004 - Small clean ups
0005-0018 - Additional debug options and WARN_ON/BUG_ON changes
0019 - Test module __init and __exit addition
0020-0021 - More functional clean ups
0022-0026 - Changes to keep nodes active
0027-0034 - Add new mas_{prev,next}_range()
0035 - Use new mas_{prev,next}_range() in mmap_region()
This patch (of 35):
Static analyser of the maple tree code noticed that the split variable is
being used to dereference into an array prior to checking the variable
itself. Fix this issue by changing the order of the statement to check
the variable first.
Link: https://lkml.kernel.org/r/20230518145544.1722059-1-Liam.Howlett@oracle.com
Link: https://lkml.kernel.org/r/20230518145544.1722059-2-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: David Binderman <dcb314@hotmail.com>
Reviewed-by: Peng Zhang<zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Check the write offset end bounds before using it as the offset into the
pivot array. This avoids a possible out-of-bounds access on the pivot
array if the write extends to the last slot in the node, in which case the
node maximum should be used as the end pivot.
akpm: this doesn't affect any current callers, but new users of mapletree
may encounter this problem if backported into earlier kernels, so let's
fix it in -stable kernels in case of this.
Link: https://lkml.kernel.org/r/20230506024752.2550-1-zhangpeng.00@bytedance.com
Fixes: 54a611b605 ("Maple Tree: add new data structure")
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Make mas->min and mas->max point to a node range instead of a leaf entry
range. This allows mas to still be usable after mas_empty_area() returns.
Users would get unexpected results from other operations on the maple
state after calling the affected function.
For example, x86 MAP_32BIT mmap() acts as if there is no suitable gap when
there should be one.
Link: https://lkml.kernel.org/r/20230505145829.74574-1-zhangpeng.00@bytedance.com
Fixes: 54a611b605 ("Maple Tree: add new data structure")
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reported-by: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
Reported-by: Tad <support@spotco.us>
Reported-by: Michael Keyes <mgkeyes@vigovproductions.net>
Link: https://lore.kernel.org/linux-mm/32f156ba80010fd97dbaf0a0cdfc84366608624d.camel@intel.com/
Link: https://lore.kernel.org/linux-mm/e6108286ac025c268964a7ead3aab9899f9bc6e9.camel@spotco.us/
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Tested-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In the case of reverse allocation, mas->index and mas->last do not point
to the correct allocation range, which will cause users to get incorrect
allocation results, so fix it. If the user does not use it in a specific
way, this bug will not be triggered.
This is a bug, but only VMA uses it now, the way VMA is used now will
not trigger it. There is a possibility that a user will trigger it in
the future.
Also re-check whether the size is still satisfied after the lower bound
was increased, which is a corner case and is incorrect in previous
versions.
Link: https://lkml.kernel.org/r/20230419093625.99201-1-zhangpeng.00@bytedance.com
Fixes: 54a611b605 ("Maple Tree: add new data structure")
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The type of variable pointed to by pivs is unsigned long, but the type
used in sizeof is a pointer type. Change it to unsigned long.
This change has no runtime effect, as sizeof(ul) == sizeof(ul *).
Link: https://lkml.kernel.org/r/20230411023513.15227-1-zhangpeng.00@bytedance.com
Fixes: 54a611b605 ("Maple Tree: add new data structure")
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reported-by: David Binderman <dcb314@hotmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Simplify code of mas_wr_node_walk() without changing functionality, and
improve readability. Remove some special judgments. Instead of
dynamically recording the min and max in the loop, get the final min and
max directly at the end.
Link: https://lkml.kernel.org/r/20230314124203.91572-3-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The internal function of mas_awalk() was incorrectly skipping the last
entry in a node, which could potentially be NULL. This is only a problem
for the left-most node in the tree - otherwise that NULL would not exist.
Fix mas_awalk() by using the metadata to obtain the end of the node for
the loop and the logical pivot as apposed to the raw pivot value.
Link: https://lkml.kernel.org/r/20230414145728.4067069-2-Liam.Howlett@oracle.com
Fixes: 54a611b605 ("Maple Tree: add new data structure")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stop using maple state min/max for the range by passing through pointers
for those values. This will allow the maple state to be reused without
resetting.
Also add some logic to fail out early on searching with invalid
arguments.
Link: https://lkml.kernel.org/r/20230414145728.4067069-1-Liam.Howlett@oracle.com
Fixes: 54a611b605 ("Maple Tree: add new data structure")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In mas_alloc_nodes(), "node->node_count = 0" means to initialize the
node_count field of the new node, but the node may not be a new node. It
may be a node that existed before and node_count has a value, setting it
to 0 will cause a memory leak. At this time, mas->alloc->total will be
greater than the actual number of nodes in the linked list, which may
cause many other errors. For example, out-of-bounds access in
mas_pop_node(), and mas_pop_node() may return addresses that should not be
used. Fix it by initializing node_count only for new nodes.
Also, by the way, an if-else statement was removed to simplify the code.
Link: https://lkml.kernel.org/r/20230411041005.26205-1-zhangpeng.00@bytedance.com
Fixes: 54a611b605 ("Maple Tree: add new data structure")
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There is a concurrency bug that may cause the wrong value to be loaded
when a CPU is modifying the maple tree.
CPU1:
mtree_insert_range()
mas_insert()
mas_store_root()
...
mas_root_expand()
...
rcu_assign_pointer(mas->tree->ma_root, mte_mk_root(mas->node));
ma_set_meta(node, maple_leaf_64, 0, slot); <---IP
CPU2:
mtree_load()
mtree_lookup_walk()
ma_data_end();
When CPU1 is about to execute the instruction pointed to by IP, the
ma_data_end() executed by CPU2 may return the wrong end position, which
will cause the value loaded by mtree_load() to be wrong.
An example of triggering the bug:
Add mdelay(100) between rcu_assign_pointer() and ma_set_meta() in
mas_root_expand().
static DEFINE_MTREE(tree);
int work(void *p) {
unsigned long val;
for (int i = 0 ; i< 30; ++i) {
val = (unsigned long)mtree_load(&tree, 8);
mdelay(5);
pr_info("%lu",val);
}
return 0;
}
mt_init_flags(&tree, MT_FLAGS_USE_RCU);
mtree_insert(&tree, 0, (void*)12345, GFP_KERNEL);
run_thread(work)
mtree_insert(&tree, 1, (void*)56789, GFP_KERNEL);
In RCU mode, mtree_load() should always return the value before or after
the data structure is modified, and in this example mtree_load(&tree, 8)
may return 56789 which is not expected, it should always return NULL. Fix
it by put ma_set_meta() before rcu_assign_pointer().
Link: https://lkml.kernel.org/r/20230314124203.91572-4-zhangpeng.00@bytedance.com
Fixes: 54a611b605 ("Maple Tree: add new data structure")
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
if (likely(offset > end))
max = pivots[offset];
The above code should be changed to if (likely(offset < end)), which is
correct. This affects the correctness of ma_data_end(). Now it seems
that the final result will not be wrong, but it is best to change it.
This patch does not change the code as above, because it simplifies the
code by the way.
Link: https://lkml.kernel.org/r/20230314124203.91572-1-zhangpeng.00@bytedance.com
Link: https://lkml.kernel.org/r/20230314124203.91572-2-zhangpeng.00@bytedance.com
Fixes: 54a611b605 ("Maple Tree: add new data structure")
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Dereferencing RCU objects within the RCU callback without the RCU check
has caused lockdep to complain. Fix the RCU dereferencing by using the
RCU callback lock to ensure the operation is safe.
Also stop creating a new lock to use for dereferencing during destruction
of the tree or subtree. Instead, pass through a pointer to the tree that
has the lock that is held for RCU dereferencing checking. It also does
not make sense to use the maple state in the freeing scenario as the tree
walk is a special case where the tree no longer has the normal encodings
and parent pointers.
Link: https://lkml.kernel.org/r/20230227173632.3292573-8-surenb@google.com
Fixes: 54a611b605 ("Maple Tree: add new data structure")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: Suren Baghdasaryan <surenb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add an smp_rmb() before reading the parent pointer to ensure that anything
read from the node prior to the parent pointer hasn't been reordered ahead
of this check.
The is necessary for RCU mode.
Link: https://lkml.kernel.org/r/20230227173632.3292573-7-surenb@google.com
Fixes: 54a611b605 ("Maple Tree: add new data structure")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
During the development of the maple tree, the strategy of freeing multiple
nodes changed and, in the process, the pivots were reused to store
pointers to dead nodes. To ensure the readers see accurate pivots, the
writers need to mark the nodes as dead and call smp_wmb() to ensure any
readers can identify the node as dead before using the pivot values.
There were two places where the old method of marking the node as dead
without smp_wmb() were being used, which resulted in RCU readers seeing
the wrong pivot value before seeing the node was dead. Fix this race
condition by using mte_set_node_dead() which has the smp_wmb() call to
ensure the race is closed.
Add a WARN_ON() to the ma_free_rcu() call to ensure all nodes being freed
are marked as dead to ensure there are no other call paths besides the two
updated paths.
This is necessary for the RCU mode of the maple tree.
Link: https://lkml.kernel.org/r/20230227173632.3292573-6-surenb@google.com
Fixes: 54a611b605 ("Maple Tree: add new data structure")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The call to mte_set_dead_node() before the smp_wmb() already calls
smp_wmb() so this is not needed. This is an optimization for the RCU mode
of the maple tree.
Link: https://lkml.kernel.org/r/20230227173632.3292573-5-surenb@google.com
Fixes: 54a611b605 ("Maple Tree: add new data structure")
Signed-off-by: Liam Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
