![Sage Weil](/assets/img/avatar_default.png)
The ceph_pagelist is a simple list of whole pages, strung together via their lru list_head. It facilitates encoding to a "buffer" of unknown size. Allow its use in place of the ceph_msg page vector. This will be used to fix the huge buffer preallocation woes of MDS reconnection. Signed-off-by: Sage Weil <sage@newdream.net>
55 lines
1.1 KiB
C
55 lines
1.1 KiB
C
|
|
#include <linux/pagemap.h>
|
|
#include <linux/highmem.h>
|
|
|
|
#include "pagelist.h"
|
|
|
|
int ceph_pagelist_release(struct ceph_pagelist *pl)
|
|
{
|
|
if (pl->mapped_tail)
|
|
kunmap(pl->mapped_tail);
|
|
while (!list_empty(&pl->head)) {
|
|
struct page *page = list_first_entry(&pl->head, struct page,
|
|
lru);
|
|
list_del(&page->lru);
|
|
__free_page(page);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int ceph_pagelist_addpage(struct ceph_pagelist *pl)
|
|
{
|
|
struct page *page = alloc_page(GFP_NOFS);
|
|
if (!page)
|
|
return -ENOMEM;
|
|
pl->room += PAGE_SIZE;
|
|
list_add_tail(&page->lru, &pl->head);
|
|
if (pl->mapped_tail)
|
|
kunmap(pl->mapped_tail);
|
|
pl->mapped_tail = kmap(page);
|
|
return 0;
|
|
}
|
|
|
|
int ceph_pagelist_append(struct ceph_pagelist *pl, void *buf, size_t len)
|
|
{
|
|
while (pl->room < len) {
|
|
size_t bit = pl->room;
|
|
int ret;
|
|
|
|
memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK),
|
|
buf, bit);
|
|
pl->length += bit;
|
|
pl->room -= bit;
|
|
buf += bit;
|
|
len -= bit;
|
|
ret = ceph_pagelist_addpage(pl);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK), buf, len);
|
|
pl->length += len;
|
|
pl->room -= len;
|
|
return 0;
|
|
}
|