From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 42265C47088 for ; Thu, 1 Dec 2022 13:26:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231511AbiLAN00 (ORCPT ); Thu, 1 Dec 2022 08:26:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37694 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231464AbiLAN0X (ORCPT ); Thu, 1 Dec 2022 08:26:23 -0500 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7F142A895F; Thu, 1 Dec 2022 05:26:22 -0800 (PST) Received: from fraeml734-chm.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4NNGwd4xxqz67yhg; Thu, 1 Dec 2022 21:23:13 +0800 (CST) Received: from lhrpeml500005.china.huawei.com (7.191.163.240) by fraeml734-chm.china.huawei.com (10.206.15.215) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Thu, 1 Dec 2022 14:26:20 +0100 Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.34; Thu, 1 Dec 2022 13:26:19 +0000 Date: Thu, 1 Dec 2022 13:26:18 +0000 From: Jonathan Cameron To: CC: Dan Williams , Alison Schofield , Vishal Verma , "Ben Widawsky" , Steven Rostedt , Davidlohr Bueso , Dave Jiang , , Subject: Re: [PATCH V2 03/11] cxl/mem: Implement Clear Event Records command Message-ID: <20221201132618.00006602@Huawei.com> In-Reply-To: <20221201002719.2596558-4-ira.weiny@intel.com> References: <20221201002719.2596558-1-ira.weiny@intel.com> <20221201002719.2596558-4-ira.weiny@intel.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.227.76] X-ClientProxiedBy: lhrpeml500002.china.huawei.com (7.191.160.78) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 30 Nov 2022 16:27:11 -0800 ira.weiny@intel.com wrote: > From: Ira Weiny > > CXL rev 3.0 section 8.2.9.2.3 defines the Clear Event Records mailbox > command. After an event record is read it needs to be cleared from the > event log. > > Implement cxl_clear_event_record() to clear all record retrieved from > the device. > > Each record is cleared explicitly. A clear all bit is specified but > events could arrive between a get and any final clear all operation. > This means events would be missed. > Therefore each event is cleared specifically. > > Signed-off-by: Ira Weiny I think there is a type issue on the min_t() calculation with that addressed this looks good to me. Reviewed-by: Jonathan Cameron > > --- > Changes from V1: > Clear Event Record allows for u8 handles while Get Event Record > allows for u16 records to be returned. Based on Jonathan's > feedback; allow for all event records to be handled in this > clear. Which means a double loop with potentially multiple > Clear Event payloads being sent to clear all events sent. > > Changes from RFC: > Jonathan > Clean up init of payload and use return code. > Also report any error to clear the event. > s/v3.0/rev 3.0 > --- > drivers/cxl/core/mbox.c | 61 +++++++++++++++++++++++++++++++----- > drivers/cxl/cxlmem.h | 14 +++++++++ > include/uapi/linux/cxl_mem.h | 1 + > 3 files changed, 69 insertions(+), 7 deletions(-) > > diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c > index 70b681027a3d..076a3df0ba38 100644 > --- a/drivers/cxl/core/mbox.c > +++ b/drivers/cxl/core/mbox.c > @@ -52,6 +52,7 @@ static struct cxl_mem_command cxl_mem_commands[CXL_MEM_COMMAND_ID_MAX] = { > #endif > CXL_CMD(GET_SUPPORTED_LOGS, 0, CXL_VARIABLE_PAYLOAD, CXL_CMD_FLAG_FORCE_ENABLE), > CXL_CMD(GET_EVENT_RECORD, 1, CXL_VARIABLE_PAYLOAD, 0), > + CXL_CMD(CLEAR_EVENT_RECORD, CXL_VARIABLE_PAYLOAD, 0, 0), > CXL_CMD(GET_FW_INFO, 0, 0x50, 0), > CXL_CMD(GET_PARTITION_INFO, 0, 0x20, 0), > CXL_CMD(GET_LSA, 0x8, CXL_VARIABLE_PAYLOAD, 0), > @@ -708,6 +709,42 @@ int cxl_enumerate_cmds(struct cxl_dev_state *cxlds) > } > EXPORT_SYMBOL_NS_GPL(cxl_enumerate_cmds, CXL); > > +static int cxl_clear_event_record(struct cxl_dev_state *cxlds, > + enum cxl_event_log_type log, > + struct cxl_get_event_payload *get_pl, > + u16 total) > +{ > + struct cxl_mbox_clear_event_payload payload = { > + .event_log = log, > + }; > + int cnt; > + > + /* > + * Clear Event Records uses u8 for the handle cnt while Get Event > + * Record can return up to 0xffff records. > + */ > + for (cnt = 0; cnt < total; /* cnt incremented internally */) { > + u8 nr_recs = min_t(u8, (total - cnt), > + CXL_CLEAR_EVENT_MAX_HANDLES); I might be half asleep but isn't this assuming that (total - cnt) fits in an u8? Shouldn't this be min_t(u16, ..) Also, maybe u16 cnt would be simpler. Hmm. This is safe but only because of how you call it alongside handling of a particular Get event records response (which must have fitted in the mailbox and has a longer header). Looking at this function in isolation, I think the mailbox could be small enough that we might not fit 255 records + the header. Perhaps we need a comment to say that, or at minimum a check and error return if it won't fit? > + int i, rc; > + > + for (i = 0; i < nr_recs; i++, cnt++) { > + payload.handle[i] = get_pl->records[cnt].hdr.handle; > + dev_dbg(cxlds->dev, "Event log '%s': Clearning %u\n", > + cxl_event_log_type_str(log), > + le16_to_cpu(payload.handle[i])); > + } > + payload.nr_recs = nr_recs; > + > + rc = cxl_mbox_send_cmd(cxlds, CXL_MBOX_OP_CLEAR_EVENT_RECORD, > + &payload, sizeof(payload), NULL, 0); > + if (rc) > + return rc; > + } > + > + return 0; > +} > + > static void cxl_mem_get_records_log(struct cxl_dev_state *cxlds, > enum cxl_event_log_type type) > { > @@ -732,13 +769,22 @@ static void cxl_mem_get_records_log(struct cxl_dev_state *cxlds, This feels miss named now but I can't immediately think of better naming so on that basis fine to leave it as is if you don't have a better idea!. > } > > nr_rec = le16_to_cpu(payload->record_count); > - if (trace_cxl_generic_event_enabled()) { > + if (nr_rec > 0) { > int i; > > - for (i = 0; i < nr_rec; i++) > - trace_cxl_generic_event(dev_name(cxlds->dev), > - type, > - &payload->records[i]); > + if (trace_cxl_generic_event_enabled()) { > + for (i = 0; i < nr_rec; i++) > + trace_cxl_generic_event(dev_name(cxlds->dev), > + type, > + &payload->records[i]); > + } > + > + rc = cxl_clear_event_record(cxlds, type, payload, nr_rec); > + if (rc) { > + dev_err(cxlds->dev, "Event log '%s': Failed to clear events : %d", > + cxl_event_log_type_str(type), rc); > + return; > + } > }