From patchwork Fri Dec 17 15:08:09 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Layton X-Patchwork-Id: 416051 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter1.kernel.org (8.14.4/8.14.3) with ESMTP id oBHF8NEO000693 for ; Fri, 17 Dec 2010 15:08:43 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755203Ab0LQPId (ORCPT ); Fri, 17 Dec 2010 10:08:33 -0500 Received: from mail-yx0-f174.google.com ([209.85.213.174]:51929 "EHLO mail-yx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755134Ab0LQPId (ORCPT ); Fri, 17 Dec 2010 10:08:33 -0500 Received: by mail-yx0-f174.google.com with SMTP id 3so351396yxt.19 for ; Fri, 17 Dec 2010 07:08:33 -0800 (PST) Received: by 10.151.101.15 with SMTP id d15mr2783699ybm.399.1292598513011; Fri, 17 Dec 2010 07:08:33 -0800 (PST) Received: from salusa.poochiereds.net (cpe-071-070-153-003.nc.res.rr.com [71.70.153.3]) by mx.google.com with ESMTPS id 2sm4330382anw.38.2010.12.17.07.08.31 (version=SSLv3 cipher=RC4-MD5); Fri, 17 Dec 2010 07:08:32 -0800 (PST) From: Jeff Layton To: smfrench@gmail.com Cc: linux-cifs@vger.kernel.org Subject: [PATCH 10/18] cifs: allow for different handling of received response Date: Fri, 17 Dec 2010 10:08:09 -0500 Message-Id: <1292598497-29796-11-git-send-email-jlayton@redhat.com> X-Mailer: git-send-email 1.7.3.3 In-Reply-To: <1292598497-29796-1-git-send-email-jlayton@redhat.com> References: <1292598497-29796-1-git-send-email-jlayton@redhat.com> Sender: linux-cifs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.3 (demeter1.kernel.org [140.211.167.41]); Fri, 17 Dec 2010 15:08:43 +0000 (UTC) diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c index ac7a38f..30d01bc 100644 --- a/fs/cifs/cifs_debug.c +++ b/fs/cifs/cifs_debug.c @@ -79,11 +79,11 @@ void cifs_dump_mids(struct TCP_Server_Info *server) spin_lock(&GlobalMid_Lock); list_for_each(tmp, &server->pending_mid_q) { mid_entry = list_entry(tmp, struct mid_q_entry, qhead); - cERROR(1, "State: %d Cmd: %d Pid: %d Tsk: %p Mid %d", + cERROR(1, "State: %d Cmd: %d Pid: %d Cbdata: %p Mid %d", mid_entry->midState, (int)mid_entry->command, mid_entry->pid, - mid_entry->tsk, + mid_entry->callback_data, mid_entry->mid); #ifdef CONFIG_CIFS_STATS2 cERROR(1, "IsLarge: %d buf: %p time rcv: %ld now: %ld", @@ -218,11 +218,11 @@ static int cifs_debug_data_proc_show(struct seq_file *m, void *v) mid_entry = list_entry(tmp3, struct mid_q_entry, qhead); seq_printf(m, "\tState: %d com: %d pid:" - " %d tsk: %p mid %d\n", + " %d cbdata: %p mid %d\n", mid_entry->midState, (int)mid_entry->command, mid_entry->pid, - mid_entry->tsk, + mid_entry->callback_data, mid_entry->mid); } spin_unlock(&GlobalMid_Lock); diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h index 8c3c165..db90fe0 100644 --- a/fs/cifs/cifsglob.h +++ b/fs/cifs/cifsglob.h @@ -508,6 +508,18 @@ static inline void cifs_stats_bytes_read(struct cifsTconInfo *tcon, #endif +struct mid_q_entry; + +/* + * This is the prototype for the mid callback function. When creating one, + * take special care to avoid deadlocks. Things to bear in mind: + * + * - it will be called by cifsd + * - the GlobalMid_Lock will be held + * - the mid will be removed from the pending_mid_q list + */ +typedef void (mid_callback_t)(struct mid_q_entry *mid); + /* one of these for every pending CIFS request to the server */ struct mid_q_entry { struct list_head qhead; /* mids waiting on reply from this server */ @@ -519,7 +531,8 @@ struct mid_q_entry { unsigned long when_sent; /* time when smb send finished */ unsigned long when_received; /* when demux complete (taken off wire) */ #endif - struct task_struct *tsk; /* task waiting for response */ + mid_callback_t *callback; /* call completion callback */ + void *callback_data; /* general purpose pointer for callback */ struct smb_hdr *resp_buf; /* response buffer */ int midState; /* wish this were enum but can not pass to wait_event */ __u8 command; /* smb command code */ diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index 515cafa..734fb09 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -152,6 +152,7 @@ cifs_reconnect(struct TCP_Server_Info *server) /* before reconnecting the tcp session, mark the smb session (uid) and the tid bad so they are not used until reconnected */ + cFYI(1, "%s: marking sessions and tcons for reconnect", __func__); spin_lock(&cifs_tcp_ses_lock); list_for_each(tmp, &server->smb_ses_list) { ses = list_entry(tmp, struct cifsSesInfo, smb_ses_list); @@ -163,7 +164,9 @@ cifs_reconnect(struct TCP_Server_Info *server) } } spin_unlock(&cifs_tcp_ses_lock); + /* do not want to be sending data on a socket we are freeing */ + cFYI(1, "%s: tearing down socket", __func__); mutex_lock(&server->srv_mutex); if (server->ssocket) { cFYI(1, "State: 0x%x Flags: 0x%lx", server->ssocket->state, @@ -180,22 +183,22 @@ cifs_reconnect(struct TCP_Server_Info *server) kfree(server->session_key.response); server->session_key.response = NULL; server->session_key.len = 0; + mutex_unlock(&server->srv_mutex); + /* + * move in-progress mids to a private list so that we can walk it later + * without needing a lock. We'll mark them for retry after reconnect. + */ + cFYI(1, "%s: issuing mid callbacks", __func__); spin_lock(&GlobalMid_Lock); - list_for_each(tmp, &server->pending_mid_q) { - mid_entry = list_entry(tmp, struct - mid_q_entry, - qhead); - if (mid_entry->midState == MID_REQUEST_SUBMITTED) { - /* Mark other intransit requests as needing - retry so we do not immediately mark the - session bad again (ie after we reconnect - below) as they timeout too */ + list_for_each_safe(tmp, tmp2, &server->pending_mid_q) { + mid_entry = list_entry(tmp, struct mid_q_entry, qhead); + if (mid_entry->midState == MID_REQUEST_SUBMITTED) mid_entry->midState = MID_RETRY_NEEDED; - } + list_del_init(&mid_entry->qhead); + mid_entry->callback(mid_entry); } spin_unlock(&GlobalMid_Lock); - mutex_unlock(&server->srv_mutex); while ((server->tcpStatus != CifsExiting) && (server->tcpStatus != CifsGood)) { @@ -212,10 +215,9 @@ cifs_reconnect(struct TCP_Server_Info *server) if (server->tcpStatus != CifsExiting) server->tcpStatus = CifsGood; spin_unlock(&GlobalMid_Lock); - /* atomic_set(&server->inFlight,0);*/ - wake_up(&server->response_q); } } + return rc; } @@ -345,7 +347,7 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server) struct msghdr smb_msg; struct kvec iov; struct socket *csocket = server->ssocket; - struct list_head *tmp; + struct list_head *tmp, *tmp2; struct task_struct *task_to_wake = NULL; struct mid_q_entry *mid_entry; char temp; @@ -558,10 +560,9 @@ incomplete_rcv: continue; } - - task_to_wake = NULL; + mid_entry = NULL; spin_lock(&GlobalMid_Lock); - list_for_each(tmp, &server->pending_mid_q) { + list_for_each_safe(tmp, tmp2, &server->pending_mid_q) { mid_entry = list_entry(tmp, struct mid_q_entry, qhead); if ((mid_entry->mid == smb_buffer->Mid) && @@ -602,8 +603,9 @@ incomplete_rcv: mid_entry->resp_buf = smb_buffer; mid_entry->largeBuf = isLargeBuf; multi_t2_fnd: - task_to_wake = mid_entry->tsk; mid_entry->midState = MID_RESPONSE_RECEIVED; + list_del_init(&mid_entry->qhead); + mid_entry->callback(mid_entry); #ifdef CONFIG_CIFS_STATS2 mid_entry->when_received = jiffies; #endif @@ -613,9 +615,11 @@ multi_t2_fnd: server->lstrp = jiffies; break; } + mid_entry = NULL; } spin_unlock(&GlobalMid_Lock); - if (task_to_wake) { + + if (mid_entry != NULL) { /* Was previous buf put in mpx struct for multi-rsp? */ if (!isMultiRsp) { /* smb buffer will be freed by user thread */ @@ -624,7 +628,6 @@ multi_t2_fnd: else smallbuf = NULL; } - wake_up_process(task_to_wake); } else if (!is_valid_oplock_break(smb_buffer, server) && !isMultiRsp) { cERROR(1, "No task to wake, unknown frame received! " @@ -678,15 +681,12 @@ multi_t2_fnd: if (!list_empty(&server->pending_mid_q)) { spin_lock(&GlobalMid_Lock); - list_for_each(tmp, &server->pending_mid_q) { + list_for_each_safe(tmp, tmp2, &server->pending_mid_q) { mid_entry = list_entry(tmp, struct mid_q_entry, qhead); - if (mid_entry->midState == MID_REQUEST_SUBMITTED) { - cFYI(1, "Clearing Mid 0x%x - waking up ", - mid_entry->mid); - task_to_wake = mid_entry->tsk; - if (task_to_wake) - wake_up_process(task_to_wake); - } + cFYI(1, "Clearing Mid 0x%x - issuing callback", + mid_entry->mid); + list_del_init(&mid_entry->qhead); + mid_entry->callback(mid_entry); } spin_unlock(&GlobalMid_Lock); /* 1/8th of sec is more than enough time for them to exit */ diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c index 6abd144..d77b615 100644 --- a/fs/cifs/transport.c +++ b/fs/cifs/transport.c @@ -36,6 +36,12 @@ extern mempool_t *cifs_mid_poolp; +static void +wake_up_task(struct mid_q_entry *mid) +{ + wake_up_process(mid->callback_data); +} + static struct mid_q_entry * AllocMidQEntry(const struct smb_hdr *smb_buffer, struct TCP_Server_Info *server) { @@ -58,7 +64,13 @@ AllocMidQEntry(const struct smb_hdr *smb_buffer, struct TCP_Server_Info *server) /* do_gettimeofday(&temp->when_sent);*/ /* easier to use jiffies */ /* when mid allocated can be before when sent */ temp->when_alloc = jiffies; - temp->tsk = current; + + /* + * The default is for the mid to be synchronous, so the + * default callback just wakes up the current task. + */ + temp->callback = wake_up_task; + temp->callback_data = current; } atomic_inc(&midCount); @@ -367,6 +379,9 @@ sync_mid_result(struct mid_q_entry *mid, struct TCP_Server_Info *server) mid->mid, mid->midState); spin_lock(&GlobalMid_Lock); + /* ensure that it's no longer on the pending_mid_q */ + list_del_init(&mid->qhead); + switch (mid->midState) { case MID_RESPONSE_RECEIVED: spin_unlock(&GlobalMid_Lock); @@ -389,7 +404,7 @@ sync_mid_result(struct mid_q_entry *mid, struct TCP_Server_Info *server) } spin_unlock(&GlobalMid_Lock); - delete_mid(mid); + DeleteMidQEntry(mid); return rc; }