// 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> 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_objs(*pages, num_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); 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);