#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 char __user *data,					  int num_pages, bool write_page){	struct page **pages;	int got = 0;	int rc = 0; 	pages = kmalloc(sizeof(*pages) * num_pages, GFP_NOFS);	if (!pages)		return ERR_PTR(-ENOMEM); 	down_read(&current->mm->mmap_sem);	while (got < num_pages) {		rc = get_user_pages(current, current->mm,		    (unsigned long)data + ((unsigned long)got * PAGE_SIZE),		    num_pages - got, write_page, 0, pages + got, NULL);		if (rc < 0)			break;		BUG_ON(rc == 0);		got += rc;	}	up_read(&current->mm->mmap_sem);	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]);	}	kfree(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(sizeof(*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); /* * copy user data into a page vector */int ceph_copy_user_to_page_vector(struct page **pages,					 const char __user *data,					 loff_t off, size_t len){	int i = 0;	int po = off & ~PAGE_CACHE_MASK;	int left = len;	int l, bad; 	while (left > 0) {		l = min_t(int, PAGE_CACHE_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_CACHE_SIZE) {			po = 0;			i++;		}	}	return len;}EXPORT_SYMBOL(ceph_copy_user_to_page_vector); int ceph_copy_to_page_vector(struct page **pages,				    const char *data,				    loff_t off, size_t len){	int i = 0;	size_t po = off & ~PAGE_CACHE_MASK;	size_t left = len;	size_t l; 	while (left > 0) {		l = min_t(size_t, PAGE_CACHE_SIZE-po, left);		memcpy(page_address(pages[i]) + po, data, l);		data += l;		left -= l;		po += l;		if (po == PAGE_CACHE_SIZE) {			po = 0;			i++;		}	}	return len;}EXPORT_SYMBOL(ceph_copy_to_page_vector); int ceph_copy_from_page_vector(struct page **pages,				    char *data,				    loff_t off, size_t len){	int i = 0;	size_t po = off & ~PAGE_CACHE_MASK;	size_t left = len;	size_t l; 	while (left > 0) {		l = min_t(size_t, PAGE_CACHE_SIZE-po, left);		memcpy(data, page_address(pages[i]) + po, l);		data += l;		left -= l;		po += l;		if (po == PAGE_CACHE_SIZE) {			po = 0;			i++;		}	}	return len;}EXPORT_SYMBOL(ceph_copy_from_page_vector); /* * copy user data from a page vector into a user pointer */int ceph_copy_page_vector_to_user(struct page **pages,					 char __user *data,					 loff_t off, size_t len){	int i = 0;	int po = off & ~PAGE_CACHE_MASK;	int left = len;	int l, bad; 	while (left > 0) {		l = min_t(int, left, PAGE_CACHE_SIZE-po);		bad = copy_to_user(data, page_address(pages[i]) + po, l);		if (bad == l)			return -EFAULT;		data += l - bad;		left -= l - bad;		if (po) {			po += l - bad;			if (po == PAGE_CACHE_SIZE)				po = 0;		}		i++;	}	return len;}EXPORT_SYMBOL(ceph_copy_page_vector_to_user); /* * 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_CACHE_SHIFT; 	off &= ~PAGE_CACHE_MASK; 	dout("zero_page_vector_page %u~%u\n", off, len); 	/* leading partial page? */	if (off) {		int end = min((int)PAGE_CACHE_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_CACHE_SIZE) {		dout("zeroing %d %p len=%d\n", i, pages[i], len);		zero_user_segment(pages[i], 0, PAGE_CACHE_SIZE);		len -= PAGE_CACHE_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);