e5eddaae1a
Update to the head of the upstream staging branch Rename redhat patches * Previous patches 0001-0012 are now patches 0041-0052 Add 0053-RH-Add-mpathcleanup.patch * add mpathcleanup program
123 lines
3.8 KiB
Diff
123 lines
3.8 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Martin Wilck <mwilck@suse.com>
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Date: Fri, 8 Sep 2023 19:50:51 +0200
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Subject: [PATCH] libmultipath: simplify get_free_id() assuming total ordering
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If we can assume that the bindings array is totally ordered for every
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prefix, which the previous patch guarantees, the search for a free ID can be
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simplified.
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Signed-off-by: Martin Wilck <mwilck@suse.com>
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Reviewed-by: Benjamin Marzinski <bmarzins@redhat.com>
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Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
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---
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libmultipath/alias.c | 85 ++++++++++----------------------------------
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1 file changed, 18 insertions(+), 67 deletions(-)
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diff --git a/libmultipath/alias.c b/libmultipath/alias.c
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index af6565b1..66e34e31 100644
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--- a/libmultipath/alias.c
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+++ b/libmultipath/alias.c
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@@ -356,83 +356,34 @@ int get_free_id(const Bindings *bindings, const char *prefix, const char *map_ww
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{
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const struct binding *bdg;
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int i, id = 1;
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- int biggest_id = 1;
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- int smallest_bigger_id = INT_MAX;
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vector_foreach_slot(bindings, bdg, i) {
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int curr_id = scan_devname(bdg->alias, prefix);
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- /*
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- * Find an unused index - explanation of the algorithm
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- *
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- * ID: 1 = mpatha, 2 = mpathb, ...
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- *
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- * We assume the bindings are unsorted. The only constraint
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- * is that no ID occurs more than once. IDs that occur in the
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- * bindings are called "used".
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- *
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- * We call the list 1,2,3,..., exactly in this order, the list
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- * of "expected" IDs. The variable "id" always holds the next
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- * "expected" ID, IOW the last "expected" ID encountered plus 1.
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- * Thus all IDs below "id" are known to be used. However, at the
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- * end of the loop, the value of "id" isn't necessarily unused.
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- *
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- * "smallest_bigger_id" is the smallest used ID that was
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- * encountered while it was larger than the next "expected" ID
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- * at that iteration. Let X be some used ID. If all IDs below X
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- * are used and encountered in the right sequence before X, "id"
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- * will be > X when the loop ends. Otherwise, X was encountered
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- * "out of order", the condition (X > id) holds when X is
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- * encountered, and "smallest_bigger_id" will be set to X; i.e.
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- * it will be less or equal than X when the loop ends.
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- *
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- * At the end of the loop, (id < smallest_bigger_id) means that
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- * the value of "id" had been encountered neither in order nor
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- * out of order, and is thus unused. (id >= smallest_bigger_id)
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- * means that "id"'s value is in use. In this case, we play safe
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- * and use "biggest_id + 1" as the next value to try.
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- *
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- * biggest_id is always > smallest_bigger_id, except in the
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- * "perfectly ordered" case.
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- */
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- if (curr_id == id) {
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- if (id < INT_MAX)
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- id++;
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- else {
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- id = -1;
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- break;
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- }
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+ if (curr_id == -1)
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+ continue;
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+ if (id > curr_id) {
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+ condlog(0, "%s: ERROR: bindings are not sorted", __func__);
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+ return -1;
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}
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- if (curr_id > biggest_id)
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- biggest_id = curr_id;
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-
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- if (curr_id > id && curr_id < smallest_bigger_id)
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- smallest_bigger_id = curr_id;
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+ while (id < curr_id && id_already_taken(id, prefix, map_wwid))
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+ id++;
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+ if (id < curr_id)
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+ return id;
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+ id++;
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+ if (id <= 0)
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+ break;
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}
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- if (id >= smallest_bigger_id)
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- id = biggest_id < INT_MAX ? biggest_id + 1 : -1;
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-
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- if (id > 0) {
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- while(id_already_taken(id, prefix, map_wwid)) {
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- if (id == INT_MAX) {
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- id = -1;
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- break;
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- }
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- id++;
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- if (id == smallest_bigger_id) {
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- if (biggest_id == INT_MAX) {
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- id = -1;
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- break;
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- }
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- if (biggest_id >= smallest_bigger_id)
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- id = biggest_id + 1;
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- }
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- }
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+ for (; id > 0; id++) {
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+ if (!id_already_taken(id, prefix, map_wwid))
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+ break;
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}
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- if (id < 0)
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+ if (id <= 0) {
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+ id = -1;
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condlog(0, "no more available user_friendly_names");
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+ }
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return id;
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}
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