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#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 rc;
pages = kmalloc(sizeof(*pages) * num_pages, GFP_NOFS);
if (!pages)
return ERR_PTR(-ENOMEM);
down_read(¤t->mm->mmap_sem);
rc = get_user_pages(current, current->mm, (unsigned long)data,
num_pages, write_page, 0, pages, NULL);
up_read(¤t->mm->mmap_sem);
if (rc < num_pages)
goto fail;
return pages;
fail:
ceph_put_page_vector(pages, rc > 0 ? rc : 0, 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);
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