mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-11-01 17:08:10 +00:00
4546548789
This is a new generic kernel FIFO implementation.
The current kernel fifo API is not very widely used, because it has to
many constrains. Only 17 files in the current 2.6.31-rc5 used it.
FIFO's are like list's a very basic thing and a kfifo API which handles
the most use case would save a lot of development time and memory
resources.
I think this are the reasons why kfifo is not in use:
- The API is to simple, important functions are missing
- A fifo can be only allocated dynamically
- There is a requirement of a spinlock whether you need it or not
- There is no support for data records inside a fifo
So I decided to extend the kfifo in a more generic way without blowing up
the API to much. The new API has the following benefits:
- Generic usage: For kernel internal use and/or device driver.
- Provide an API for the most use case.
- Slim API: The whole API provides 25 functions.
- Linux style habit.
- DECLARE_KFIFO, DEFINE_KFIFO and INIT_KFIFO Macros
- Direct copy_to_user from the fifo and copy_from_user into the fifo.
- The kfifo itself is an in place member of the using data structure, this save an
indirection access and does not waste the kernel allocator.
- Lockless access: if only one reader and one writer is active on the fifo,
which is the common use case, no additional locking is necessary.
- Remove spinlock - give the user the freedom of choice what kind of locking to use if
one is required.
- Ability to handle records. Three type of records are supported:
- Variable length records between 0-255 bytes, with a record size
field of 1 bytes.
- Variable length records between 0-65535 bytes, with a record size
field of 2 bytes.
- Fixed size records, which no record size field.
- Preserve memory resource.
- Performance!
- Easy to use!
This patch:
Since most users want to have the kfifo as part of another object,
reorganize the code to allow including struct kfifo in another data
structure. This requires changing the kfifo_alloc and kfifo_init
prototypes so that we pass an existing kfifo pointer into them. This
patch changes the implementation and all existing users.
[akpm@linux-foundation.org: fix warning]
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
133 lines
4.2 KiB
C
133 lines
4.2 KiB
C
/*
|
|
* iSCSI over TCP/IP Data-Path lib
|
|
*
|
|
* Copyright (C) 2008 Mike Christie
|
|
* Copyright (C) 2008 Red Hat, Inc. All rights reserved.
|
|
* maintained by open-iscsi@googlegroups.com
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published
|
|
* by the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful, but
|
|
* WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* General Public License for more details.
|
|
*
|
|
* See the file COPYING included with this distribution for more details.
|
|
*/
|
|
|
|
#ifndef LIBISCSI_TCP_H
|
|
#define LIBISCSI_TCP_H
|
|
|
|
#include <scsi/libiscsi.h>
|
|
|
|
struct iscsi_tcp_conn;
|
|
struct iscsi_segment;
|
|
struct sk_buff;
|
|
struct hash_desc;
|
|
|
|
typedef int iscsi_segment_done_fn_t(struct iscsi_tcp_conn *,
|
|
struct iscsi_segment *);
|
|
|
|
struct iscsi_segment {
|
|
unsigned char *data;
|
|
unsigned int size;
|
|
unsigned int copied;
|
|
unsigned int total_size;
|
|
unsigned int total_copied;
|
|
|
|
struct hash_desc *hash;
|
|
unsigned char padbuf[ISCSI_PAD_LEN];
|
|
unsigned char recv_digest[ISCSI_DIGEST_SIZE];
|
|
unsigned char digest[ISCSI_DIGEST_SIZE];
|
|
unsigned int digest_len;
|
|
|
|
struct scatterlist *sg;
|
|
void *sg_mapped;
|
|
unsigned int sg_offset;
|
|
|
|
iscsi_segment_done_fn_t *done;
|
|
};
|
|
|
|
/* Socket connection recieve helper */
|
|
struct iscsi_tcp_recv {
|
|
struct iscsi_hdr *hdr;
|
|
struct iscsi_segment segment;
|
|
|
|
/* Allocate buffer for BHS + AHS */
|
|
uint32_t hdr_buf[64];
|
|
|
|
/* copied and flipped values */
|
|
int datalen;
|
|
};
|
|
|
|
struct iscsi_tcp_conn {
|
|
struct iscsi_conn *iscsi_conn;
|
|
void *dd_data;
|
|
int stop_stage; /* conn_stop() flag: *
|
|
* stop to recover, *
|
|
* stop to terminate */
|
|
/* control data */
|
|
struct iscsi_tcp_recv in; /* TCP receive context */
|
|
/* CRC32C (Rx) LLD should set this is they do not offload */
|
|
struct hash_desc *rx_hash;
|
|
};
|
|
|
|
struct iscsi_tcp_task {
|
|
uint32_t exp_datasn; /* expected target's R2TSN/DataSN */
|
|
int data_offset;
|
|
struct iscsi_r2t_info *r2t; /* in progress solict R2T */
|
|
struct iscsi_pool r2tpool;
|
|
struct kfifo r2tqueue;
|
|
void *dd_data;
|
|
};
|
|
|
|
enum {
|
|
ISCSI_TCP_SEGMENT_DONE, /* curr seg has been processed */
|
|
ISCSI_TCP_SKB_DONE, /* skb is out of data */
|
|
ISCSI_TCP_CONN_ERR, /* iscsi layer has fired a conn err */
|
|
ISCSI_TCP_SUSPENDED, /* conn is suspended */
|
|
};
|
|
|
|
extern void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn);
|
|
extern int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
|
|
unsigned int offset, bool offloaded, int *status);
|
|
extern void iscsi_tcp_cleanup_task(struct iscsi_task *task);
|
|
extern int iscsi_tcp_task_init(struct iscsi_task *task);
|
|
extern int iscsi_tcp_task_xmit(struct iscsi_task *task);
|
|
|
|
/* segment helpers */
|
|
extern int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn);
|
|
extern int iscsi_tcp_segment_done(struct iscsi_tcp_conn *tcp_conn,
|
|
struct iscsi_segment *segment, int recv,
|
|
unsigned copied);
|
|
extern void iscsi_tcp_segment_unmap(struct iscsi_segment *segment);
|
|
|
|
extern void iscsi_segment_init_linear(struct iscsi_segment *segment,
|
|
void *data, size_t size,
|
|
iscsi_segment_done_fn_t *done,
|
|
struct hash_desc *hash);
|
|
extern int
|
|
iscsi_segment_seek_sg(struct iscsi_segment *segment,
|
|
struct scatterlist *sg_list, unsigned int sg_count,
|
|
unsigned int offset, size_t size,
|
|
iscsi_segment_done_fn_t *done, struct hash_desc *hash);
|
|
|
|
/* digest helpers */
|
|
extern void iscsi_tcp_dgst_header(struct hash_desc *hash, const void *hdr,
|
|
size_t hdrlen,
|
|
unsigned char digest[ISCSI_DIGEST_SIZE]);
|
|
extern struct iscsi_cls_conn *
|
|
iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
|
|
uint32_t conn_idx);
|
|
extern void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn);
|
|
|
|
/* misc helpers */
|
|
extern int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session);
|
|
extern void iscsi_tcp_r2tpool_free(struct iscsi_session *session);
|
|
|
|
extern void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
|
|
struct iscsi_stats *stats);
|
|
#endif /* LIBISCSI_TCP_H */
|