v4.19.13 snapshot.
diff --git a/net/ceph/pagevec.c b/net/ceph/pagevec.c
new file mode 100644
index 0000000..d3736f5
--- /dev/null
+++ b/net/ceph/pagevec.c
@@ -0,0 +1,199 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/ceph/ceph_debug.h>
+
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/file.h>
+#include <linux/namei.h>
+#include <linux/writeback.h>
+
+#include <linux/ceph/libceph.h>
+
+/*
+ * build a vector of user pages
+ */
+struct page **ceph_get_direct_page_vector(const void __user *data,
+ int num_pages, bool write_page)
+{
+ struct page **pages;
+ int got = 0;
+ int rc = 0;
+
+ pages = kmalloc_array(num_pages, sizeof(*pages), GFP_NOFS);
+ if (!pages)
+ return ERR_PTR(-ENOMEM);
+
+ while (got < num_pages) {
+ rc = get_user_pages_fast(
+ (unsigned long)data + ((unsigned long)got * PAGE_SIZE),
+ num_pages - got, write_page, pages + got);
+ if (rc < 0)
+ break;
+ BUG_ON(rc == 0);
+ got += rc;
+ }
+ if (rc < 0)
+ goto fail;
+ return pages;
+
+fail:
+ ceph_put_page_vector(pages, got, false);
+ return ERR_PTR(rc);
+}
+EXPORT_SYMBOL(ceph_get_direct_page_vector);
+
+void ceph_put_page_vector(struct page **pages, int num_pages, bool dirty)
+{
+ int i;
+
+ for (i = 0; i < num_pages; i++) {
+ if (dirty)
+ set_page_dirty_lock(pages[i]);
+ put_page(pages[i]);
+ }
+ kvfree(pages);
+}
+EXPORT_SYMBOL(ceph_put_page_vector);
+
+void ceph_release_page_vector(struct page **pages, int num_pages)
+{
+ int i;
+
+ for (i = 0; i < num_pages; i++)
+ __free_pages(pages[i], 0);
+ kfree(pages);
+}
+EXPORT_SYMBOL(ceph_release_page_vector);
+
+/*
+ * allocate a vector new pages
+ */
+struct page **ceph_alloc_page_vector(int num_pages, gfp_t flags)
+{
+ struct page **pages;
+ int i;
+
+ pages = kmalloc_array(num_pages, sizeof(*pages), flags);
+ if (!pages)
+ return ERR_PTR(-ENOMEM);
+ for (i = 0; i < num_pages; i++) {
+ pages[i] = __page_cache_alloc(flags);
+ if (pages[i] == NULL) {
+ ceph_release_page_vector(pages, i);
+ return ERR_PTR(-ENOMEM);
+ }
+ }
+ return pages;
+}
+EXPORT_SYMBOL(ceph_alloc_page_vector);
+
+/*
+ * copy user data into a page vector
+ */
+int ceph_copy_user_to_page_vector(struct page **pages,
+ const void __user *data,
+ loff_t off, size_t len)
+{
+ int i = 0;
+ int po = off & ~PAGE_MASK;
+ int left = len;
+ int l, bad;
+
+ while (left > 0) {
+ l = min_t(int, PAGE_SIZE-po, left);
+ bad = copy_from_user(page_address(pages[i]) + po, data, l);
+ if (bad == l)
+ return -EFAULT;
+ data += l - bad;
+ left -= l - bad;
+ po += l - bad;
+ if (po == PAGE_SIZE) {
+ po = 0;
+ i++;
+ }
+ }
+ return len;
+}
+EXPORT_SYMBOL(ceph_copy_user_to_page_vector);
+
+void ceph_copy_to_page_vector(struct page **pages,
+ const void *data,
+ loff_t off, size_t len)
+{
+ int i = 0;
+ size_t po = off & ~PAGE_MASK;
+ size_t left = len;
+
+ while (left > 0) {
+ size_t l = min_t(size_t, PAGE_SIZE-po, left);
+
+ memcpy(page_address(pages[i]) + po, data, l);
+ data += l;
+ left -= l;
+ po += l;
+ if (po == PAGE_SIZE) {
+ po = 0;
+ i++;
+ }
+ }
+}
+EXPORT_SYMBOL(ceph_copy_to_page_vector);
+
+void ceph_copy_from_page_vector(struct page **pages,
+ void *data,
+ loff_t off, size_t len)
+{
+ int i = 0;
+ size_t po = off & ~PAGE_MASK;
+ size_t left = len;
+
+ while (left > 0) {
+ size_t l = min_t(size_t, PAGE_SIZE-po, left);
+
+ memcpy(data, page_address(pages[i]) + po, l);
+ data += l;
+ left -= l;
+ po += l;
+ if (po == PAGE_SIZE) {
+ po = 0;
+ i++;
+ }
+ }
+}
+EXPORT_SYMBOL(ceph_copy_from_page_vector);
+
+/*
+ * Zero an extent within a page vector. Offset is relative to the
+ * start of the first page.
+ */
+void ceph_zero_page_vector_range(int off, int len, struct page **pages)
+{
+ int i = off >> PAGE_SHIFT;
+
+ off &= ~PAGE_MASK;
+
+ dout("zero_page_vector_page %u~%u\n", off, len);
+
+ /* leading partial page? */
+ if (off) {
+ int end = min((int)PAGE_SIZE, off + len);
+ dout("zeroing %d %p head from %d\n", i, pages[i],
+ (int)off);
+ zero_user_segment(pages[i], off, end);
+ len -= (end - off);
+ i++;
+ }
+ while (len >= PAGE_SIZE) {
+ dout("zeroing %d %p len=%d\n", i, pages[i], len);
+ zero_user_segment(pages[i], 0, PAGE_SIZE);
+ len -= PAGE_SIZE;
+ i++;
+ }
+ /* trailing partial page? */
+ if (len) {
+ dout("zeroing %d %p tail to %d\n", i, pages[i], (int)len);
+ zero_user_segment(pages[i], 0, len);
+ }
+}
+EXPORT_SYMBOL(ceph_zero_page_vector_range);