From 2d86dbc97094ea4cfc2204fdefd7d07685496189 Mon Sep 17 00:00:00 2001 From: Pavel Shilovsky Date: Mon, 6 Feb 2012 15:59:18 +0400 Subject: [PATCH] CIFS: Introduce credit-based flow control and send no more than credits value requests at once. For SMB/CIFS it's trivial: increment this value by receiving any message and decrement by sending one. Reviewed-by: Jeff Layton Signed-off-by: Pavel Shilovsky Signed-off-by: Steve French --- fs/cifs/cifsglob.h | 11 +++++++---- fs/cifs/cifsproto.h | 3 +++ fs/cifs/cifssmb.c | 13 +++++-------- fs/cifs/connect.c | 14 ++++++-------- fs/cifs/misc.c | 19 +++++++++++++++++++ fs/cifs/transport.c | 44 ++++++++++++++++++++------------------------ 6 files changed, 60 insertions(+), 44 deletions(-) diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h index fb78bc9..d55de96 100644 --- a/fs/cifs/cifsglob.h +++ b/fs/cifs/cifsglob.h @@ -250,8 +250,9 @@ struct TCP_Server_Info { bool noblocksnd; /* use blocking sendmsg */ bool noautotune; /* do not autotune send buf sizes */ bool tcp_nodelay; + int credits; /* send no more requests at once */ unsigned int in_flight; /* number of requests on the wire to server */ - spinlock_t req_lock; /* protect the value above */ + spinlock_t req_lock; /* protect the two values above */ struct mutex srv_mutex; struct task_struct *tsk; char server_GUID[16]; @@ -314,12 +315,14 @@ in_flight(struct TCP_Server_Info *server) return num; } -static inline void -dec_in_flight(struct TCP_Server_Info *server) +static inline bool +has_credits(struct TCP_Server_Info *server) { + int num; spin_lock(&server->req_lock); - server->in_flight--; + num = server->credits; spin_unlock(&server->req_lock); + return num > 0; } /* diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h index 6f4e243..47a769e 100644 --- a/fs/cifs/cifsproto.h +++ b/fs/cifs/cifsproto.h @@ -88,6 +88,9 @@ extern int SendReceiveBlockingLock(const unsigned int xid, struct smb_hdr *in_buf , struct smb_hdr *out_buf, int *bytes_returned); +extern void cifs_add_credits(struct TCP_Server_Info *server, + const unsigned int add); +extern void cifs_set_credits(struct TCP_Server_Info *server, const int val); extern int checkSMB(struct smb_hdr *smb, __u16 mid, unsigned int length); extern bool is_valid_oplock_break(struct smb_hdr *smb, struct TCP_Server_Info *); diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c index d7cbcfa..70aac35c 100644 --- a/fs/cifs/cifssmb.c +++ b/fs/cifs/cifssmb.c @@ -461,7 +461,7 @@ CIFSSMBNegotiate(unsigned int xid, struct cifs_ses *ses) server->maxReq = min_t(unsigned int, le16_to_cpu(rsp->MaxMpxCount), cifs_max_pending); - server->oplocks = server->maxReq > 1 ? enable_oplocks : false; + cifs_set_credits(server, server->maxReq); server->maxBuf = le16_to_cpu(rsp->MaxBufSize); server->max_vcs = le16_to_cpu(rsp->MaxNumberVcs); /* even though we do not use raw we might as well set this @@ -569,7 +569,7 @@ CIFSSMBNegotiate(unsigned int xid, struct cifs_ses *ses) little endian */ server->maxReq = min_t(unsigned int, le16_to_cpu(pSMBr->MaxMpxCount), cifs_max_pending); - server->oplocks = server->maxReq > 1 ? enable_oplocks : false; + cifs_set_credits(server, server->maxReq); /* probably no need to store and check maxvcs */ server->maxBuf = le32_to_cpu(pSMBr->MaxBufferSize); server->max_rw = le32_to_cpu(pSMBr->MaxRawSize); @@ -721,8 +721,7 @@ cifs_echo_callback(struct mid_q_entry *mid) struct TCP_Server_Info *server = mid->callback_data; DeleteMidQEntry(mid); - dec_in_flight(server); - wake_up(&server->request_q); + cifs_add_credits(server, 1); } int @@ -1674,8 +1673,7 @@ cifs_readv_callback(struct mid_q_entry *mid) queue_work(system_nrt_wq, &rdata->work); DeleteMidQEntry(mid); - dec_in_flight(server); - wake_up(&server->request_q); + cifs_add_credits(server, 1); } /* cifs_async_readv - send an async write, and set up mid to handle result */ @@ -2115,8 +2113,7 @@ cifs_writev_callback(struct mid_q_entry *mid) queue_work(system_nrt_wq, &wdata->work); DeleteMidQEntry(mid); - dec_in_flight(tcon->ses->server); - wake_up(&tcon->ses->server->request_q); + cifs_add_credits(tcon->ses->server, 1); } /* cifs_async_writev - send an async write, and set up mid to handle result */ diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index ed91abc..1d48901 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -642,14 +642,10 @@ static void clean_demultiplex_info(struct TCP_Server_Info *server) spin_unlock(&GlobalMid_Lock); wake_up_all(&server->response_q); - /* Check if we have blocked requests that need to free. */ + /* check if we have blocked requests that need to free */ spin_lock(&server->req_lock); - if (server->in_flight >= server->maxReq) - server->in_flight = server->maxReq - 1; - /* - * We do not want to set the max_pending too low or we could end up - * with the counter going negative. - */ + if (server->credits <= 0) + server->credits = 1; spin_unlock(&server->req_lock); /* * Although there should not be any requests blocked on this queue it @@ -1906,7 +1902,7 @@ cifs_get_tcp_session(struct smb_vol *volume_info) tcp_ses->noautotune = volume_info->noautotune; tcp_ses->tcp_nodelay = volume_info->sockopt_tcp_nodelay; tcp_ses->in_flight = 0; - tcp_ses->maxReq = 1; /* enough to send negotiate request */ + tcp_ses->credits = 1; init_waitqueue_head(&tcp_ses->response_q); init_waitqueue_head(&tcp_ses->request_q); INIT_LIST_HEAD(&tcp_ses->pending_mid_q); @@ -3757,9 +3753,11 @@ int cifs_negotiate_protocol(unsigned int xid, struct cifs_ses *ses) if (server->maxBuf != 0) return 0; + cifs_set_credits(server, 1); rc = CIFSSMBNegotiate(xid, ses); if (rc == -EAGAIN) { /* retry only once on 1st time connection */ + cifs_set_credits(server, 1); rc = CIFSSMBNegotiate(xid, ses); if (rc == -EAGAIN) rc = -EHOSTDOWN; diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c index 703ef5c..c273c12 100644 --- a/fs/cifs/misc.c +++ b/fs/cifs/misc.c @@ -690,3 +690,22 @@ backup_cred(struct cifs_sb_info *cifs_sb) return false; } + +void +cifs_add_credits(struct TCP_Server_Info *server, const unsigned int add) +{ + spin_lock(&server->req_lock); + server->credits += add; + server->in_flight--; + spin_unlock(&server->req_lock); + wake_up(&server->request_q); +} + +void +cifs_set_credits(struct TCP_Server_Info *server, const int val) +{ + spin_lock(&server->req_lock); + server->credits = val; + server->oplocks = val > 1 ? enable_oplocks : false; + spin_unlock(&server->req_lock); +} diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c index e2673aa..e5202dd 100644 --- a/fs/cifs/transport.c +++ b/fs/cifs/transport.c @@ -262,16 +262,16 @@ wait_for_free_request(struct TCP_Server_Info *server, const int long_op) if (long_op == CIFS_ASYNC_OP) { /* oplock breaks must not be held up */ server->in_flight++; + server->credits--; spin_unlock(&server->req_lock); return 0; } while (1) { - if (server->in_flight >= server->maxReq) { + if (server->credits <= 0) { spin_unlock(&server->req_lock); cifs_num_waiters_inc(server); - wait_event(server->request_q, - in_flight(server) < server->maxReq); + wait_event(server->request_q, has_credits(server)); cifs_num_waiters_dec(server); spin_lock(&server->req_lock); } else { @@ -280,12 +280,16 @@ wait_for_free_request(struct TCP_Server_Info *server, const int long_op) return -ENOENT; } - /* can not count locking commands against total - as they are allowed to block on server */ + /* + * Can not count locking commands against total + * as they are allowed to block on server. + */ /* update # of requests on the wire to server */ - if (long_op != CIFS_BLOCKING_OP) + if (long_op != CIFS_BLOCKING_OP) { + server->credits--; server->in_flight++; + } spin_unlock(&server->req_lock); break; } @@ -360,7 +364,7 @@ cifs_call_async(struct TCP_Server_Info *server, struct kvec *iov, mid = AllocMidQEntry(hdr, server); if (mid == NULL) { mutex_unlock(&server->srv_mutex); - dec_in_flight(server); + cifs_add_credits(server, 1); wake_up(&server->request_q); return -ENOMEM; } @@ -393,7 +397,7 @@ cifs_call_async(struct TCP_Server_Info *server, struct kvec *iov, return rc; out_err: delete_mid(mid); - dec_in_flight(server); + cifs_add_credits(server, 1); wake_up(&server->request_q); return rc; } @@ -565,8 +569,7 @@ SendReceive2(const unsigned int xid, struct cifs_ses *ses, mutex_unlock(&ses->server->srv_mutex); cifs_small_buf_release(in_buf); /* Update # of requests on wire to server */ - dec_in_flight(ses->server); - wake_up(&ses->server->request_q); + cifs_add_credits(ses->server, 1); return rc; } rc = cifs_sign_smb2(iov, n_vec, ses->server, &midQ->sequence_number); @@ -602,8 +605,7 @@ SendReceive2(const unsigned int xid, struct cifs_ses *ses, midQ->callback = DeleteMidQEntry; spin_unlock(&GlobalMid_Lock); cifs_small_buf_release(in_buf); - dec_in_flight(ses->server); - wake_up(&ses->server->request_q); + cifs_add_credits(ses->server, 1); return rc; } spin_unlock(&GlobalMid_Lock); @@ -613,8 +615,7 @@ SendReceive2(const unsigned int xid, struct cifs_ses *ses, rc = cifs_sync_mid_result(midQ, ses->server); if (rc != 0) { - dec_in_flight(ses->server); - wake_up(&ses->server->request_q); + cifs_add_credits(ses->server, 1); return rc; } @@ -638,8 +639,7 @@ SendReceive2(const unsigned int xid, struct cifs_ses *ses, midQ->resp_buf = NULL; out: delete_mid(midQ); - dec_in_flight(ses->server); - wake_up(&ses->server->request_q); + cifs_add_credits(ses->server, 1); return rc; } @@ -689,8 +689,7 @@ SendReceive(const unsigned int xid, struct cifs_ses *ses, if (rc) { mutex_unlock(&ses->server->srv_mutex); /* Update # of requests on wire to server */ - dec_in_flight(ses->server); - wake_up(&ses->server->request_q); + cifs_add_credits(ses->server, 1); return rc; } @@ -722,8 +721,7 @@ SendReceive(const unsigned int xid, struct cifs_ses *ses, /* no longer considered to be "in-flight" */ midQ->callback = DeleteMidQEntry; spin_unlock(&GlobalMid_Lock); - dec_in_flight(ses->server); - wake_up(&ses->server->request_q); + cifs_add_credits(ses->server, 1); return rc; } spin_unlock(&GlobalMid_Lock); @@ -731,8 +729,7 @@ SendReceive(const unsigned int xid, struct cifs_ses *ses, rc = cifs_sync_mid_result(midQ, ses->server); if (rc != 0) { - dec_in_flight(ses->server); - wake_up(&ses->server->request_q); + cifs_add_credits(ses->server, 1); return rc; } @@ -748,8 +745,7 @@ SendReceive(const unsigned int xid, struct cifs_ses *ses, rc = cifs_check_receive(midQ, ses->server, 0); out: delete_mid(midQ); - dec_in_flight(ses->server); - wake_up(&ses->server->request_q); + cifs_add_credits(ses->server, 1); return rc; } -- 2.7.4