lib: remove prio_heap

The prio_heap code is unused since commit 889ed9ceaa97 ("cgroup: remove
css_scan_tasks()").  It should be compiled out to shrink the binary
kernel size which can be done via introducing CONFIG_PRIO_HEAD or by
removing the code.

We can simply recover the code from git when needed, so it would be
better to remove it IMO.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Francesco Fusco <ffusco@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: George Spelvin <linux@horizon.com>
Cc: Mark Salter <msalter@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 1 insertions, 71 deletions

diff --git a/lib/Makefile b/lib/Makefile
index d6b4bc496408..eb95e0fdcca5 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -11,7 +11,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \
          rbtree.o radix-tree.o dump_stack.o timerqueue.o\
          idr.o int_sqrt.o extable.o \
          sha1.o md5.o irq_regs.o reciprocal_div.o argv_split.o \
-         proportions.o flex_proportions.o prio_heap.o ratelimit.o show_mem.o \
+         proportions.o flex_proportions.o ratelimit.o show_mem.o \
          is_single_threaded.o plist.o decompress.o kobject_uevent.o \
          earlycpio.o
 
diff --git a/lib/prio_heap.c b/lib/prio_heap.c
deleted file mode 100644
index a7af6f85eca8..000000000000
--- a/lib/prio_heap.c
+++ /dev/null
@@ -1,70 +0,0 @@
-/*
- * Simple insertion-only static-sized priority heap containing
- * pointers, based on CLR, chapter 7
- */
-
-#include <linux/slab.h>
-#include <linux/prio_heap.h>
-
-int heap_init(struct ptr_heap *heap, size_t size, gfp_t gfp_mask,
-              int (*gt)(void *, void *))
-{
-        heap->ptrs = kmalloc(size, gfp_mask);
-        if (!heap->ptrs)
-                return -ENOMEM;
-        heap->size = 0;
-        heap->max = size / sizeof(void *);
-        heap->gt = gt;
-        return 0;
-}
-
-void heap_free(struct ptr_heap *heap)
-{
-        kfree(heap->ptrs);
-}
-
-void *heap_insert(struct ptr_heap *heap, void *p)
-{
-        void *res;
-        void **ptrs = heap->ptrs;
-        int pos;
-
-        if (heap->size < heap->max) {
-                /* Heap insertion */
-                pos = heap->size++;
-                while (pos > 0 && heap->gt(p, ptrs[(pos-1)/2])) {
-                        ptrs[pos] = ptrs[(pos-1)/2];
-                        pos = (pos-1)/2;
-                }
-                ptrs[pos] = p;
-                return NULL;
-        }
-
-        /* The heap is full, so something will have to be dropped */
-
-        /* If the new pointer is greater than the current max, drop it */
-        if (heap->gt(p, ptrs[0]))
-                return p;
-
-        /* Replace the current max and heapify */
-        res = ptrs[0];
-        ptrs[0] = p;
-        pos = 0;
-
-        while (1) {
-                int left = 2 * pos + 1;
-                int right = 2 * pos + 2;
-                int largest = pos;
-                if (left < heap->size && heap->gt(ptrs[left], p))
-                        largest = left;
-                if (right < heap->size && heap->gt(ptrs[right], ptrs[largest]))
-                        largest = right;
-                if (largest == pos)
-                        break;
-                /* Push p down the heap one level and bump one up */
-                ptrs[pos] = ptrs[largest];
-                ptrs[largest] = p;
-                pos = largest;
-        }
-        return res;
-}