linux/fs/ceph/pagelist.h
Sage Weil 58bb3b374b ceph: support ceph_pagelist for message payload
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>
2009-12-23 12:12:31 -08:00

55 lines
1.3 KiB
C

#ifndef __FS_CEPH_PAGELIST_H
#define __FS_CEPH_PAGELIST_H
#include <linux/list.h>
struct ceph_pagelist {
struct list_head head;
void *mapped_tail;
size_t length;
size_t room;
};
static inline void ceph_pagelist_init(struct ceph_pagelist *pl)
{
INIT_LIST_HEAD(&pl->head);
pl->mapped_tail = NULL;
pl->length = 0;
pl->room = 0;
}
extern int ceph_pagelist_release(struct ceph_pagelist *pl);
extern int ceph_pagelist_append(struct ceph_pagelist *pl, void *d, size_t l);
static inline int ceph_pagelist_encode_64(struct ceph_pagelist *pl, u64 v)
{
__le64 ev = cpu_to_le64(v);
return ceph_pagelist_append(pl, &ev, sizeof(ev));
}
static inline int ceph_pagelist_encode_32(struct ceph_pagelist *pl, u32 v)
{
__le32 ev = cpu_to_le32(v);
return ceph_pagelist_append(pl, &ev, sizeof(ev));
}
static inline int ceph_pagelist_encode_16(struct ceph_pagelist *pl, u16 v)
{
__le16 ev = cpu_to_le16(v);
return ceph_pagelist_append(pl, &ev, sizeof(ev));
}
static inline int ceph_pagelist_encode_8(struct ceph_pagelist *pl, u8 v)
{
return ceph_pagelist_append(pl, &v, 1);
}
static inline int ceph_pagelist_encode_string(struct ceph_pagelist *pl,
char *s, size_t len)
{
int ret = ceph_pagelist_encode_32(pl, len);
if (ret)
return ret;
if (len)
return ceph_pagelist_append(pl, s, len);
return 0;
}
#endif