linux/fs/cifs/smbdirect.h
David Howells 3d78fe73fa cifs: Build the RDMA SGE list directly from an iterator
In the depths of the cifs RDMA code, extract part of an iov iterator
directly into an SGE list without going through an intermediate
scatterlist.

Note that this doesn't support extraction from an IOBUF- or UBUF-type
iterator (ie. user-supplied buffer).  The assumption is that the higher
layers will extract those to a BVEC-type iterator first and do whatever is
required to stop the pages from going away.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Rohith Surabattula <rohiths.msft@gmail.com>
cc: Tom Talpey <tom@talpey.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: linux-rdma@vger.kernel.org

Link: https://lore.kernel.org/r/166697260361.61150.5064013393408112197.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/166732032518.3186319.1859601819981624629.stgit@warthog.procyon.org.uk/ # rfc
Signed-off-by: Steve French <stfrench@microsoft.com>
2023-02-20 18:36:02 -06:00

320 lines
8.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Copyright (C) 2017, Microsoft Corporation.
*
* Author(s): Long Li <longli@microsoft.com>
*/
#ifndef _SMBDIRECT_H
#define _SMBDIRECT_H
#ifdef CONFIG_CIFS_SMB_DIRECT
#define cifs_rdma_enabled(server) ((server)->rdma)
#include "cifsglob.h"
#include <rdma/ib_verbs.h>
#include <rdma/rdma_cm.h>
#include <linux/mempool.h>
extern int rdma_readwrite_threshold;
extern int smbd_max_frmr_depth;
extern int smbd_keep_alive_interval;
extern int smbd_max_receive_size;
extern int smbd_max_fragmented_recv_size;
extern int smbd_max_send_size;
extern int smbd_send_credit_target;
extern int smbd_receive_credit_max;
enum keep_alive_status {
KEEP_ALIVE_NONE,
KEEP_ALIVE_PENDING,
KEEP_ALIVE_SENT,
};
enum smbd_connection_status {
SMBD_CREATED,
SMBD_CONNECTING,
SMBD_CONNECTED,
SMBD_NEGOTIATE_FAILED,
SMBD_DISCONNECTING,
SMBD_DISCONNECTED,
SMBD_DESTROYED
};
/*
* The context for the SMBDirect transport
* Everything related to the transport is here. It has several logical parts
* 1. RDMA related structures
* 2. SMBDirect connection parameters
* 3. Memory registrations
* 4. Receive and reassembly queues for data receive path
* 5. mempools for allocating packets
*/
struct smbd_connection {
enum smbd_connection_status transport_status;
/* RDMA related */
struct rdma_cm_id *id;
struct ib_qp_init_attr qp_attr;
struct ib_pd *pd;
struct ib_cq *send_cq, *recv_cq;
struct ib_device_attr dev_attr;
int ri_rc;
struct completion ri_done;
wait_queue_head_t conn_wait;
wait_queue_head_t disconn_wait;
struct completion negotiate_completion;
bool negotiate_done;
struct work_struct disconnect_work;
struct work_struct post_send_credits_work;
spinlock_t lock_new_credits_offered;
int new_credits_offered;
/* Connection parameters defined in [MS-SMBD] 3.1.1.1 */
int receive_credit_max;
int send_credit_target;
int max_send_size;
int max_fragmented_recv_size;
int max_fragmented_send_size;
int max_receive_size;
int keep_alive_interval;
int max_readwrite_size;
enum keep_alive_status keep_alive_requested;
int protocol;
atomic_t send_credits;
atomic_t receive_credits;
int receive_credit_target;
int fragment_reassembly_remaining;
/* Memory registrations */
/* Maximum number of RDMA read/write outstanding on this connection */
int responder_resources;
/* Maximum number of pages in a single RDMA write/read on this connection */
int max_frmr_depth;
/*
* If payload is less than or equal to the threshold,
* use RDMA send/recv to send upper layer I/O.
* If payload is more than the threshold,
* use RDMA read/write through memory registration for I/O.
*/
int rdma_readwrite_threshold;
enum ib_mr_type mr_type;
struct list_head mr_list;
spinlock_t mr_list_lock;
/* The number of available MRs ready for memory registration */
atomic_t mr_ready_count;
atomic_t mr_used_count;
wait_queue_head_t wait_mr;
struct work_struct mr_recovery_work;
/* Used by transport to wait until all MRs are returned */
wait_queue_head_t wait_for_mr_cleanup;
/* Activity accoutning */
atomic_t send_pending;
wait_queue_head_t wait_send_pending;
wait_queue_head_t wait_post_send;
/* Receive queue */
struct list_head receive_queue;
int count_receive_queue;
spinlock_t receive_queue_lock;
struct list_head empty_packet_queue;
int count_empty_packet_queue;
spinlock_t empty_packet_queue_lock;
wait_queue_head_t wait_receive_queues;
/* Reassembly queue */
struct list_head reassembly_queue;
spinlock_t reassembly_queue_lock;
wait_queue_head_t wait_reassembly_queue;
/* total data length of reassembly queue */
int reassembly_data_length;
int reassembly_queue_length;
/* the offset to first buffer in reassembly queue */
int first_entry_offset;
bool send_immediate;
wait_queue_head_t wait_send_queue;
/*
* Indicate if we have received a full packet on the connection
* This is used to identify the first SMBD packet of a assembled
* payload (SMB packet) in reassembly queue so we can return a
* RFC1002 length to upper layer to indicate the length of the SMB
* packet received
*/
bool full_packet_received;
struct workqueue_struct *workqueue;
struct delayed_work idle_timer_work;
/* Memory pool for preallocating buffers */
/* request pool for RDMA send */
struct kmem_cache *request_cache;
mempool_t *request_mempool;
/* response pool for RDMA receive */
struct kmem_cache *response_cache;
mempool_t *response_mempool;
/* for debug purposes */
unsigned int count_get_receive_buffer;
unsigned int count_put_receive_buffer;
unsigned int count_reassembly_queue;
unsigned int count_enqueue_reassembly_queue;
unsigned int count_dequeue_reassembly_queue;
unsigned int count_send_empty;
};
enum smbd_message_type {
SMBD_NEGOTIATE_RESP,
SMBD_TRANSFER_DATA,
};
#define SMB_DIRECT_RESPONSE_REQUESTED 0x0001
/* SMBD negotiation request packet [MS-SMBD] 2.2.1 */
struct smbd_negotiate_req {
__le16 min_version;
__le16 max_version;
__le16 reserved;
__le16 credits_requested;
__le32 preferred_send_size;
__le32 max_receive_size;
__le32 max_fragmented_size;
} __packed;
/* SMBD negotiation response packet [MS-SMBD] 2.2.2 */
struct smbd_negotiate_resp {
__le16 min_version;
__le16 max_version;
__le16 negotiated_version;
__le16 reserved;
__le16 credits_requested;
__le16 credits_granted;
__le32 status;
__le32 max_readwrite_size;
__le32 preferred_send_size;
__le32 max_receive_size;
__le32 max_fragmented_size;
} __packed;
/* SMBD data transfer packet with payload [MS-SMBD] 2.2.3 */
struct smbd_data_transfer {
__le16 credits_requested;
__le16 credits_granted;
__le16 flags;
__le16 reserved;
__le32 remaining_data_length;
__le32 data_offset;
__le32 data_length;
__le32 padding;
__u8 buffer[];
} __packed;
/* The packet fields for a registered RDMA buffer */
struct smbd_buffer_descriptor_v1 {
__le64 offset;
__le32 token;
__le32 length;
} __packed;
/* Maximum number of SGEs used by smbdirect.c in any send work request */
#define SMBDIRECT_MAX_SEND_SGE 6
/* The context for a SMBD request */
struct smbd_request {
struct smbd_connection *info;
struct ib_cqe cqe;
/* the SGE entries for this work request */
struct ib_sge sge[SMBDIRECT_MAX_SEND_SGE];
int num_sge;
/* SMBD packet header follows this structure */
u8 packet[];
};
/* Maximum number of SGEs used by smbdirect.c in any receive work request */
#define SMBDIRECT_MAX_RECV_SGE 1
/* The context for a SMBD response */
struct smbd_response {
struct smbd_connection *info;
struct ib_cqe cqe;
struct ib_sge sge;
enum smbd_message_type type;
/* Link to receive queue or reassembly queue */
struct list_head list;
/* Indicate if this is the 1st packet of a payload */
bool first_segment;
/* SMBD packet header and payload follows this structure */
u8 packet[];
};
/* Create a SMBDirect session */
struct smbd_connection *smbd_get_connection(
struct TCP_Server_Info *server, struct sockaddr *dstaddr);
/* Reconnect SMBDirect session */
int smbd_reconnect(struct TCP_Server_Info *server);
/* Destroy SMBDirect session */
void smbd_destroy(struct TCP_Server_Info *server);
/* Interface for carrying upper layer I/O through send/recv */
int smbd_recv(struct smbd_connection *info, struct msghdr *msg);
int smbd_send(struct TCP_Server_Info *server,
int num_rqst, struct smb_rqst *rqst);
enum mr_state {
MR_READY,
MR_REGISTERED,
MR_INVALIDATED,
MR_ERROR
};
struct smbd_mr {
struct smbd_connection *conn;
struct list_head list;
enum mr_state state;
struct ib_mr *mr;
struct sg_table sgt;
enum dma_data_direction dir;
union {
struct ib_reg_wr wr;
struct ib_send_wr inv_wr;
};
struct ib_cqe cqe;
bool need_invalidate;
struct completion invalidate_done;
};
/* Interfaces to register and deregister MR for RDMA read/write */
struct smbd_mr *smbd_register_mr(
struct smbd_connection *info, struct iov_iter *iter,
bool writing, bool need_invalidate);
int smbd_deregister_mr(struct smbd_mr *mr);
#else
#define cifs_rdma_enabled(server) 0
struct smbd_connection {};
static inline void *smbd_get_connection(
struct TCP_Server_Info *server, struct sockaddr *dstaddr) {return NULL;}
static inline int smbd_reconnect(struct TCP_Server_Info *server) {return -1; }
static inline void smbd_destroy(struct TCP_Server_Info *server) {}
static inline int smbd_recv(struct smbd_connection *info, struct msghdr *msg) {return -1; }
static inline int smbd_send(struct TCP_Server_Info *server, int num_rqst, struct smb_rqst *rqst) {return -1; }
#endif
#endif