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-rw-r--r--kernel/pid.c36
1 files changed, 36 insertions, 0 deletions
diff --git a/kernel/pid.c b/kernel/pid.c
index 8387e8c68193..ed89a732432c 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -145,6 +145,23 @@ static int alloc_pidmap(void)
return -1;
}
+static int next_pidmap(int last)
+{
+ int offset;
+ pidmap_t *map;
+
+ offset = (last + 1) & BITS_PER_PAGE_MASK;
+ map = &pidmap_array[(last + 1)/BITS_PER_PAGE];
+ for (; map < &pidmap_array[PIDMAP_ENTRIES]; map++, offset = 0) {
+ if (unlikely(!map->page))
+ continue;
+ offset = find_next_bit((map)->page, BITS_PER_PAGE, offset);
+ if (offset < BITS_PER_PAGE)
+ return mk_pid(map, offset);
+ }
+ return -1;
+}
+
fastcall void put_pid(struct pid *pid)
{
if (!pid)
@@ -303,6 +320,25 @@ struct pid *find_get_pid(pid_t nr)
}
/*
+ * Used by proc to find the first pid that is greater then or equal to nr.
+ *
+ * If there is a pid at nr this function is exactly the same as find_pid.
+ */
+struct pid *find_ge_pid(int nr)
+{
+ struct pid *pid;
+
+ do {
+ pid = find_pid(nr);
+ if (pid)
+ break;
+ nr = next_pidmap(nr);
+ } while (nr > 0);
+
+ return pid;
+}
+
+/*
* The pid hash table is scaled according to the amount of memory in the
* machine. From a minimum of 16 slots up to 4096 slots at one gigabyte or
* more.