maple_tree: add gap support, slot and pivot sizes for maple copy

Add plumbing work for using maple copy as a normal node for a source of
copy operations.  This is needed later.

Link: https://lkml.kernel.org/r/20260130205935.2559335-17-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Andrew Ballance <andrewjballance@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christian Kujau <lists@nerdbynature.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/maple_tree.h b/include/linux/maple_tree.h
index e99e16ac1c6da993e770175f52a590b27dea3482..db6a02788902aa485e6270240fc5b7c912364bad 100644 (file)
--- a/include/linux/maple_tree.h
+++ b/include/linux/maple_tree.h
@@ -165,6 +165,7 @@ struct maple_copy {
        } src[4];
        /* Simulated node */
        void __rcu *slot[3];
+       unsigned long gap[3];
        unsigned long min;
        union {
                unsigned long pivot[3];

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 499cae720251f3ebe0fc60878a3dc30c213bde05..9c701ee7412ca7bf0e3158b17dde055a3cc4ecc4 100644 (file)
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -101,6 +101,7 @@ static const unsigned long mt_max[] = {
        [maple_leaf_64]         = ULONG_MAX,
        [maple_range_64]        = ULONG_MAX,
        [maple_arange_64]       = ULONG_MAX,
+       [maple_copy]            = ULONG_MAX,
 };
 #define mt_node_max(x) mt_max[mte_node_type(x)]
 #endif
@@ -110,6 +111,7 @@ static const unsigned char mt_slots[] = {
        [maple_leaf_64]         = MAPLE_RANGE64_SLOTS,
        [maple_range_64]        = MAPLE_RANGE64_SLOTS,
        [maple_arange_64]       = MAPLE_ARANGE64_SLOTS,
+       [maple_copy]            = 3,
 };
 #define mt_slot_count(x) mt_slots[mte_node_type(x)]
 
@@ -118,6 +120,7 @@ static const unsigned char mt_pivots[] = {
        [maple_leaf_64]         = MAPLE_RANGE64_SLOTS - 1,
        [maple_range_64]        = MAPLE_RANGE64_SLOTS - 1,
        [maple_arange_64]       = MAPLE_ARANGE64_SLOTS - 1,
+       [maple_copy]            = 3,
 };
 #define mt_pivot_count(x) mt_pivots[mte_node_type(x)]
 
@@ -126,6 +129,7 @@ static const unsigned char mt_min_slots[] = {
        [maple_leaf_64]         = (MAPLE_RANGE64_SLOTS / 2) - 2,
        [maple_range_64]        = (MAPLE_RANGE64_SLOTS / 2) - 2,
        [maple_arange_64]       = (MAPLE_ARANGE64_SLOTS / 2) - 1,
+       [maple_copy]            = 1, /* Should never be used */
 };
 #define mt_min_slot_count(x) mt_min_slots[mte_node_type(x)]
 
@@ -627,6 +631,7 @@ static inline unsigned long *ma_gaps(struct maple_node *node,
        case maple_arange_64:
                return node->ma64.gap;
        case maple_copy:
+               return node->cp.gap;
        case maple_range_64:
        case maple_leaf_64:
        case maple_dense: