| Message ID | 20221112234308.23823-1-richard.weiyang@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | maple_tree: should get pivots boundary by type | expand |
May I ask who would pick this? On Sat, Nov 12, 2022 at 11:43:08PM +0000, Wei Yang wrote: >We should get pivots boundary by type. > >Fixes: 54a611b60590 (Maple Tree: add new data structure) >Signed-off-by: Wei Yang <richard.weiyang@gmail.com> >CC: Liam R. Howlett <Liam.Howlett@Oracle.com> >Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> > >--- >* kernel build looks good >--- > lib/maple_tree.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > >diff --git a/lib/maple_tree.c b/lib/maple_tree.c >index 73e2e6434e2f..2123d1930a9b 100644 >--- a/lib/maple_tree.c >+++ b/lib/maple_tree.c >@@ -669,12 +669,13 @@ static inline unsigned long mte_pivot(const struct maple_enode *mn, > unsigned char piv) > { > struct maple_node *node = mte_to_node(mn); >+ enum maple_type type = mte_node_type(mn); > >- if (piv >= mt_pivots[piv]) { >+ if (piv >= mt_pivots[type]) { > WARN_ON(1); > return 0; > } >- switch (mte_node_type(mn)) { >+ switch (type) { > case maple_arange_64: > return node->ma64.pivot[piv]; > case maple_range_64: >-- >2.33.1
On Sat, 12 Nov 2022 23:43:08 +0000 Wei Yang <richard.weiyang@gmail.com> wrote: > We should get pivots boundary by type. > When fixing a bug, please always fully describe the runtime effects of that bug. I see from earlier review that the bug could result in overindexing mt_pivots[], but Liam says this code isn't presently used, but mas_alloc() calls mte_pivot(), so I'm all confused. > --- a/lib/maple_tree.c > +++ b/lib/maple_tree.c > @@ -669,12 +669,13 @@ static inline unsigned long mte_pivot(const struct maple_enode *mn, > unsigned char piv) > { > struct maple_node *node = mte_to_node(mn); > + enum maple_type type = mte_node_type(mn); > > - if (piv >= mt_pivots[piv]) { > + if (piv >= mt_pivots[type]) { > WARN_ON(1); > return 0; > } > - switch (mte_node_type(mn)) { > + switch (type) { > case maple_arange_64: > return node->ma64.pivot[piv]; > case maple_range_64: > -- > 2.33.1 >
* Andrew Morton <akpm@linux-foundation.org> [230123 16:43]: > On Sat, 12 Nov 2022 23:43:08 +0000 Wei Yang <richard.weiyang@gmail.com> wrote: > > > We should get pivots boundary by type. > > > > When fixing a bug, please always fully describe the runtime effects of > that bug. > > I see from earlier review that the bug could result in overindexing > mt_pivots[], but Liam says this code isn't presently used, but > mas_alloc() calls mte_pivot(), so I'm all confused. Correct. The function mas_alloc() is... very much not well named. It is called from mtree_alloc_range() which will put a temporary value into the tree so that you may store over that value later without allocating memory later. It's about allocating a range, not memory. Perhaps mas_reserve() would have been better, in retrospect. Anyways, it's not used by the mm code right now, but it's certainly a bug. > > > > --- a/lib/maple_tree.c > > +++ b/lib/maple_tree.c > > @@ -669,12 +669,13 @@ static inline unsigned long mte_pivot(const struct maple_enode *mn, > > unsigned char piv) > > { > > struct maple_node *node = mte_to_node(mn); > > + enum maple_type type = mte_node_type(mn); > > > > - if (piv >= mt_pivots[piv]) { > > + if (piv >= mt_pivots[type]) { > > WARN_ON(1); > > return 0; > > } > > - switch (mte_node_type(mn)) { > > + switch (type) { > > case maple_arange_64: > > return node->ma64.pivot[piv]; > > case maple_range_64: > > -- > > 2.33.1 > >
diff --git a/lib/maple_tree.c b/lib/maple_tree.c index 73e2e6434e2f..2123d1930a9b 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -669,12 +669,13 @@ static inline unsigned long mte_pivot(const struct maple_enode *mn, unsigned char piv) { struct maple_node *node = mte_to_node(mn); + enum maple_type type = mte_node_type(mn); - if (piv >= mt_pivots[piv]) { + if (piv >= mt_pivots[type]) { WARN_ON(1); return 0; } - switch (mte_node_type(mn)) { + switch (type) { case maple_arange_64: return node->ma64.pivot[piv]; case maple_range_64: