84 lines
2.1 KiB
Diff
84 lines
2.1 KiB
Diff
From f1740455253d0b7ccbcff3d81c8bfe96e2233762 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Christian=20G=C3=B6ttsche?= <cgzones@googlemail.com>
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Date: Tue, 19 Jul 2022 17:30:43 +0200
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Subject: [PATCH] libsepol: optimize ebitmap_xor
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Content-type: text/plain
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Iterate on nodes instead of single bits to save node resolution for each
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single bit.
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Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
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Acked-by: James Carter <jwcart2@gmail.com>
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---
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libsepol/src/ebitmap.c | 49 ++++++++++++++++++++++++++++++++++++------
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1 file changed, 43 insertions(+), 6 deletions(-)
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diff --git a/libsepol/src/ebitmap.c b/libsepol/src/ebitmap.c
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index 6dbbddfdb467..7d26f9493120 100644
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--- a/libsepol/src/ebitmap.c
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+++ b/libsepol/src/ebitmap.c
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@@ -117,14 +117,51 @@ int ebitmap_and(ebitmap_t *dst, const ebitmap_t *e1, const ebitmap_t *e2)
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int ebitmap_xor(ebitmap_t *dst, const ebitmap_t *e1, const ebitmap_t *e2)
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{
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- unsigned int i, length = max(ebitmap_length(e1), ebitmap_length(e2));
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+ const ebitmap_node_t *n1, *n2;
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+ ebitmap_node_t *new, *prev = NULL;
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+ uint32_t startbit;
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+ MAPTYPE map;
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+
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ebitmap_init(dst);
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- for (i=0; i < length; i++) {
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- int val = ebitmap_get_bit(e1, i) ^ ebitmap_get_bit(e2, i);
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- int rc = ebitmap_set_bit(dst, i, val);
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- if (rc < 0)
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- return rc;
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+
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+ n1 = e1->node;
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+ n2 = e2->node;
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+ while (n1 || n2) {
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+ if (n1 && n2 && n1->startbit == n2->startbit) {
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+ startbit = n1->startbit;
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+ map = n1->map ^ n2->map;
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+ n1 = n1->next;
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+ n2 = n2->next;
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+ } else if (!n2 || (n1 && n1->startbit < n2->startbit)) {
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+ startbit = n1->startbit;
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+ map = n1->map;
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+ n1 = n1->next;
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+ } else {
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+ startbit = n2->startbit;
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+ map = n2->map;
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+ n2 = n2->next;
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+ }
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+
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+ if (map != 0) {
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+ new = malloc(sizeof(ebitmap_node_t));
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+ if (!new) {
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+ ebitmap_destroy(dst);
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+ return -ENOMEM;
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+ }
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+ new->startbit = startbit;
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+ new->map = map;
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+ new->next = NULL;
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+ if (prev)
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+ prev->next = new;
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+ else
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+ dst->node = new;
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+ prev = new;
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+ }
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}
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+
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+ if (prev)
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+ dst->highbit = prev->startbit + MAPSIZE;
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+
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return 0;
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}
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--
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2.38.1
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