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| author | Wei Yang <richard.weiyang@gmail.com> | 2024-09-08 16:05:54 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-11-06 01:56:24 +0100 |
| commit | 5059aa6334fcf4b7ddd672255aec5835aecd32b6 (patch) | |
| tree | b7faa9d6059ec223855cbd063cea5e0ef15aec26 | |
| parent | maple_tree: remove maple_big_node.parent (diff) | |
| download | linux-5059aa6334fcf4b7ddd672255aec5835aecd32b6.tar.xz linux-5059aa6334fcf4b7ddd672255aec5835aecd32b6.zip | |
maple_tree: memset maple_big_node as a whole
In mast_fill_bnode(), we first clear some fields of maple_big_node and set
the 'type' unconditionally before return. This means we won't leverage
any information in maple_big_node and it is safe to clear the whole
structure.
In maple_big_node, we define slot and padding/gap in a union. And based
on current definition of MAPLE_BIG_NODE_SLOTS/GAPS, padding is always less
than slot and part of the gap is overlapped by slot.
For example on 64bit system:
MAPLE_BIG_NODE_SLOT is 34
MAPLE_BIG_NODE_GAP is 21
With this knowledge, current code may clear some space by twice. And
this could be avoid by clearing the structure as a whole.
Link: https://lkml.kernel.org/r/20240908140554.20378-3-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | lib/maple_tree.c | 5 |
1 files changed, 1 insertions, 4 deletions
diff --git a/lib/maple_tree.c b/lib/maple_tree.c index 04cd5ce2a33c..c5987244ff63 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -3157,10 +3157,7 @@ static inline void mast_fill_bnode(struct maple_subtree_state *mast, bool cp = true; unsigned char split; - memset(mast->bn->gap, 0, sizeof(unsigned long) * ARRAY_SIZE(mast->bn->gap)); - memset(mast->bn->slot, 0, sizeof(unsigned long) * ARRAY_SIZE(mast->bn->slot)); - memset(mast->bn->pivot, 0, sizeof(unsigned long) * ARRAY_SIZE(mast->bn->pivot)); - mast->bn->b_end = 0; + memset(mast->bn, 0, sizeof(struct maple_big_node)); if (mte_is_root(mas->node)) { cp = false; |