v4.19.13 snapshot.
diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c
new file mode 100644
index 0000000..d8078de
--- /dev/null
+++ b/mm/percpu-vm.c
@@ -0,0 +1,379 @@
+/*
+ * mm/percpu-vm.c - vmalloc area based chunk allocation
+ *
+ * Copyright (C) 2010 SUSE Linux Products GmbH
+ * Copyright (C) 2010 Tejun Heo <tj@kernel.org>
+ *
+ * This file is released under the GPLv2.
+ *
+ * Chunks are mapped into vmalloc areas and populated page by page.
+ * This is the default chunk allocator.
+ */
+
+static struct page *pcpu_chunk_page(struct pcpu_chunk *chunk,
+ unsigned int cpu, int page_idx)
+{
+ /* must not be used on pre-mapped chunk */
+ WARN_ON(chunk->immutable);
+
+ return vmalloc_to_page((void *)pcpu_chunk_addr(chunk, cpu, page_idx));
+}
+
+/**
+ * pcpu_get_pages - get temp pages array
+ *
+ * Returns pointer to array of pointers to struct page which can be indexed
+ * with pcpu_page_idx(). Note that there is only one array and accesses
+ * should be serialized by pcpu_alloc_mutex.
+ *
+ * RETURNS:
+ * Pointer to temp pages array on success.
+ */
+static struct page **pcpu_get_pages(void)
+{
+ static struct page **pages;
+ size_t pages_size = pcpu_nr_units * pcpu_unit_pages * sizeof(pages[0]);
+
+ lockdep_assert_held(&pcpu_alloc_mutex);
+
+ if (!pages)
+ pages = pcpu_mem_zalloc(pages_size, GFP_KERNEL);
+ return pages;
+}
+
+/**
+ * pcpu_free_pages - free pages which were allocated for @chunk
+ * @chunk: chunk pages were allocated for
+ * @pages: array of pages to be freed, indexed by pcpu_page_idx()
+ * @page_start: page index of the first page to be freed
+ * @page_end: page index of the last page to be freed + 1
+ *
+ * Free pages [@page_start and @page_end) in @pages for all units.
+ * The pages were allocated for @chunk.
+ */
+static void pcpu_free_pages(struct pcpu_chunk *chunk,
+ struct page **pages, int page_start, int page_end)
+{
+ unsigned int cpu;
+ int i;
+
+ for_each_possible_cpu(cpu) {
+ for (i = page_start; i < page_end; i++) {
+ struct page *page = pages[pcpu_page_idx(cpu, i)];
+
+ if (page)
+ __free_page(page);
+ }
+ }
+}
+
+/**
+ * pcpu_alloc_pages - allocates pages for @chunk
+ * @chunk: target chunk
+ * @pages: array to put the allocated pages into, indexed by pcpu_page_idx()
+ * @page_start: page index of the first page to be allocated
+ * @page_end: page index of the last page to be allocated + 1
+ * @gfp: allocation flags passed to the underlying allocator
+ *
+ * Allocate pages [@page_start,@page_end) into @pages for all units.
+ * The allocation is for @chunk. Percpu core doesn't care about the
+ * content of @pages and will pass it verbatim to pcpu_map_pages().
+ */
+static int pcpu_alloc_pages(struct pcpu_chunk *chunk,
+ struct page **pages, int page_start, int page_end,
+ gfp_t gfp)
+{
+ unsigned int cpu, tcpu;
+ int i;
+
+ gfp |= __GFP_HIGHMEM;
+
+ for_each_possible_cpu(cpu) {
+ for (i = page_start; i < page_end; i++) {
+ struct page **pagep = &pages[pcpu_page_idx(cpu, i)];
+
+ *pagep = alloc_pages_node(cpu_to_node(cpu), gfp, 0);
+ if (!*pagep)
+ goto err;
+ }
+ }
+ return 0;
+
+err:
+ while (--i >= page_start)
+ __free_page(pages[pcpu_page_idx(cpu, i)]);
+
+ for_each_possible_cpu(tcpu) {
+ if (tcpu == cpu)
+ break;
+ for (i = page_start; i < page_end; i++)
+ __free_page(pages[pcpu_page_idx(tcpu, i)]);
+ }
+ return -ENOMEM;
+}
+
+/**
+ * pcpu_pre_unmap_flush - flush cache prior to unmapping
+ * @chunk: chunk the regions to be flushed belongs to
+ * @page_start: page index of the first page to be flushed
+ * @page_end: page index of the last page to be flushed + 1
+ *
+ * Pages in [@page_start,@page_end) of @chunk are about to be
+ * unmapped. Flush cache. As each flushing trial can be very
+ * expensive, issue flush on the whole region at once rather than
+ * doing it for each cpu. This could be an overkill but is more
+ * scalable.
+ */
+static void pcpu_pre_unmap_flush(struct pcpu_chunk *chunk,
+ int page_start, int page_end)
+{
+ flush_cache_vunmap(
+ pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
+ pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
+}
+
+static void __pcpu_unmap_pages(unsigned long addr, int nr_pages)
+{
+ unmap_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT);
+}
+
+/**
+ * pcpu_unmap_pages - unmap pages out of a pcpu_chunk
+ * @chunk: chunk of interest
+ * @pages: pages array which can be used to pass information to free
+ * @page_start: page index of the first page to unmap
+ * @page_end: page index of the last page to unmap + 1
+ *
+ * For each cpu, unmap pages [@page_start,@page_end) out of @chunk.
+ * Corresponding elements in @pages were cleared by the caller and can
+ * be used to carry information to pcpu_free_pages() which will be
+ * called after all unmaps are finished. The caller should call
+ * proper pre/post flush functions.
+ */
+static void pcpu_unmap_pages(struct pcpu_chunk *chunk,
+ struct page **pages, int page_start, int page_end)
+{
+ unsigned int cpu;
+ int i;
+
+ for_each_possible_cpu(cpu) {
+ for (i = page_start; i < page_end; i++) {
+ struct page *page;
+
+ page = pcpu_chunk_page(chunk, cpu, i);
+ WARN_ON(!page);
+ pages[pcpu_page_idx(cpu, i)] = page;
+ }
+ __pcpu_unmap_pages(pcpu_chunk_addr(chunk, cpu, page_start),
+ page_end - page_start);
+ }
+}
+
+/**
+ * pcpu_post_unmap_tlb_flush - flush TLB after unmapping
+ * @chunk: pcpu_chunk the regions to be flushed belong to
+ * @page_start: page index of the first page to be flushed
+ * @page_end: page index of the last page to be flushed + 1
+ *
+ * Pages [@page_start,@page_end) of @chunk have been unmapped. Flush
+ * TLB for the regions. This can be skipped if the area is to be
+ * returned to vmalloc as vmalloc will handle TLB flushing lazily.
+ *
+ * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
+ * for the whole region.
+ */
+static void pcpu_post_unmap_tlb_flush(struct pcpu_chunk *chunk,
+ int page_start, int page_end)
+{
+ flush_tlb_kernel_range(
+ pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
+ pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
+}
+
+static int __pcpu_map_pages(unsigned long addr, struct page **pages,
+ int nr_pages)
+{
+ return map_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT,
+ PAGE_KERNEL, pages);
+}
+
+/**
+ * pcpu_map_pages - map pages into a pcpu_chunk
+ * @chunk: chunk of interest
+ * @pages: pages array containing pages to be mapped
+ * @page_start: page index of the first page to map
+ * @page_end: page index of the last page to map + 1
+ *
+ * For each cpu, map pages [@page_start,@page_end) into @chunk. The
+ * caller is responsible for calling pcpu_post_map_flush() after all
+ * mappings are complete.
+ *
+ * This function is responsible for setting up whatever is necessary for
+ * reverse lookup (addr -> chunk).
+ */
+static int pcpu_map_pages(struct pcpu_chunk *chunk,
+ struct page **pages, int page_start, int page_end)
+{
+ unsigned int cpu, tcpu;
+ int i, err;
+
+ for_each_possible_cpu(cpu) {
+ err = __pcpu_map_pages(pcpu_chunk_addr(chunk, cpu, page_start),
+ &pages[pcpu_page_idx(cpu, page_start)],
+ page_end - page_start);
+ if (err < 0)
+ goto err;
+
+ for (i = page_start; i < page_end; i++)
+ pcpu_set_page_chunk(pages[pcpu_page_idx(cpu, i)],
+ chunk);
+ }
+ return 0;
+err:
+ for_each_possible_cpu(tcpu) {
+ if (tcpu == cpu)
+ break;
+ __pcpu_unmap_pages(pcpu_chunk_addr(chunk, tcpu, page_start),
+ page_end - page_start);
+ }
+ pcpu_post_unmap_tlb_flush(chunk, page_start, page_end);
+ return err;
+}
+
+/**
+ * pcpu_post_map_flush - flush cache after mapping
+ * @chunk: pcpu_chunk the regions to be flushed belong to
+ * @page_start: page index of the first page to be flushed
+ * @page_end: page index of the last page to be flushed + 1
+ *
+ * Pages [@page_start,@page_end) of @chunk have been mapped. Flush
+ * cache.
+ *
+ * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
+ * for the whole region.
+ */
+static void pcpu_post_map_flush(struct pcpu_chunk *chunk,
+ int page_start, int page_end)
+{
+ flush_cache_vmap(
+ pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
+ pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
+}
+
+/**
+ * pcpu_populate_chunk - populate and map an area of a pcpu_chunk
+ * @chunk: chunk of interest
+ * @page_start: the start page
+ * @page_end: the end page
+ * @gfp: allocation flags passed to the underlying memory allocator
+ *
+ * For each cpu, populate and map pages [@page_start,@page_end) into
+ * @chunk.
+ *
+ * CONTEXT:
+ * pcpu_alloc_mutex, does GFP_KERNEL allocation.
+ */
+static int pcpu_populate_chunk(struct pcpu_chunk *chunk,
+ int page_start, int page_end, gfp_t gfp)
+{
+ struct page **pages;
+
+ pages = pcpu_get_pages();
+ if (!pages)
+ return -ENOMEM;
+
+ if (pcpu_alloc_pages(chunk, pages, page_start, page_end, gfp))
+ return -ENOMEM;
+
+ if (pcpu_map_pages(chunk, pages, page_start, page_end)) {
+ pcpu_free_pages(chunk, pages, page_start, page_end);
+ return -ENOMEM;
+ }
+ pcpu_post_map_flush(chunk, page_start, page_end);
+
+ return 0;
+}
+
+/**
+ * pcpu_depopulate_chunk - depopulate and unmap an area of a pcpu_chunk
+ * @chunk: chunk to depopulate
+ * @page_start: the start page
+ * @page_end: the end page
+ *
+ * For each cpu, depopulate and unmap pages [@page_start,@page_end)
+ * from @chunk.
+ *
+ * CONTEXT:
+ * pcpu_alloc_mutex.
+ */
+static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk,
+ int page_start, int page_end)
+{
+ struct page **pages;
+
+ /*
+ * If control reaches here, there must have been at least one
+ * successful population attempt so the temp pages array must
+ * be available now.
+ */
+ pages = pcpu_get_pages();
+ BUG_ON(!pages);
+
+ /* unmap and free */
+ pcpu_pre_unmap_flush(chunk, page_start, page_end);
+
+ pcpu_unmap_pages(chunk, pages, page_start, page_end);
+
+ /* no need to flush tlb, vmalloc will handle it lazily */
+
+ pcpu_free_pages(chunk, pages, page_start, page_end);
+}
+
+static struct pcpu_chunk *pcpu_create_chunk(gfp_t gfp)
+{
+ struct pcpu_chunk *chunk;
+ struct vm_struct **vms;
+
+ chunk = pcpu_alloc_chunk(gfp);
+ if (!chunk)
+ return NULL;
+
+ vms = pcpu_get_vm_areas(pcpu_group_offsets, pcpu_group_sizes,
+ pcpu_nr_groups, pcpu_atom_size);
+ if (!vms) {
+ pcpu_free_chunk(chunk);
+ return NULL;
+ }
+
+ chunk->data = vms;
+ chunk->base_addr = vms[0]->addr - pcpu_group_offsets[0];
+
+ pcpu_stats_chunk_alloc();
+ trace_percpu_create_chunk(chunk->base_addr);
+
+ return chunk;
+}
+
+static void pcpu_destroy_chunk(struct pcpu_chunk *chunk)
+{
+ if (!chunk)
+ return;
+
+ pcpu_stats_chunk_dealloc();
+ trace_percpu_destroy_chunk(chunk->base_addr);
+
+ if (chunk->data)
+ pcpu_free_vm_areas(chunk->data, pcpu_nr_groups);
+ pcpu_free_chunk(chunk);
+}
+
+static struct page *pcpu_addr_to_page(void *addr)
+{
+ return vmalloc_to_page(addr);
+}
+
+static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai)
+{
+ /* no extra restriction */
+ return 0;
+}