From patchwork Fri May 15 05:34:58 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Saravana Kannan X-Patchwork-Id: 194193 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.4 required=3.0 tests=DKIMWL_WL_MED, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 43246C433E2 for ; Fri, 15 May 2020 05:35:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 18CB4206F1 for ; Fri, 15 May 2020 05:35:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="NNmMCJFs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726613AbgEOFfM (ORCPT ); Fri, 15 May 2020 01:35:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35716 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726314AbgEOFfL (ORCPT ); Fri, 15 May 2020 01:35:11 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 40CF6C05BD0B for ; Thu, 14 May 2020 22:35:10 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id h129so1416781ybc.3 for ; Thu, 14 May 2020 22:35:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=RUCHt3IUTaAuIZ5RcDy4DbI7lEInPDSWSCSV1x0aJWU=; b=NNmMCJFsnc8QFuD5OYt292G7roqEzHRNUYulBcoESHwmzCM16suaXcwxL7JDzWuXay Dz81ANTMnpkXBwhmnbiMvHbNioUQM/0Jpu3HXydj063az53GvyNz/ybUZi60vtEftqsX 5y3CuDlXPN0VWTHOizdO8em6WneEBZOh05j/7gzZ+EyL4MN+N+nBFKGcWK9B06gY26KJ EGI22WFBwOcvhbXCvYFfJ+BLuzRTTJq8pGhTf0uMvGUdpHIb43ZqlK9z+ik7oP4ePFz0 M6M70Lurbci12BP0XFdJqAvYdNFGYV/6XA+xhipiiPq+tnAWLrAKkNFkoATNHlcwVIG2 kS+w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=RUCHt3IUTaAuIZ5RcDy4DbI7lEInPDSWSCSV1x0aJWU=; b=tZtQqwdJL5SDIk3yZGGauDgTrPrVJLN/CGTb/Ox0UPNsibJCgKypIc/27RXTVaLdCV q+4QPBWahKV6seNW2EjqvHD85WDO3/M7JJhFN6yhiT5pRj8tZ/+bvASViPfNVjPARjrP Q72SzKyhAdmWuA7F+tLExniX5j+uqs9FcntITXqYVRwyoEvx0LeyYeaLV15Aoy6Xf3vi RStG3igqE3pPshe4NAHXBTaYko6Lenc+ielJuxyIWCJU+gjgECR3BSfaUB0WaAysbd6D 3ty//qZTlfsVdROidNvRHvyFGEuWTrooZ6JUM0aQW0+8cUKjaITm9J38KGWekyqnL/sn NDOw== X-Gm-Message-State: AOAM530KY1iIA4jLbQgy1in8LDYiNpK/Ta9Yhc82u1zuiGQoy46Banha Jvd5JjA3sBju7brTtMPHizo2i1ARdWhMUnc= X-Google-Smtp-Source: ABdhPJz5Il4KBtVez3mKTqB6IUL3C6pYb+iGjAt2GhlZ7PEp1DIpmYHxcPfv+5v4AeIr7I9PrnjCEiAD3DCPmSY= X-Received: by 2002:a25:ba8b:: with SMTP id s11mr2591447ybg.310.1589520908664; Thu, 14 May 2020 22:35:08 -0700 (PDT) Date: Thu, 14 May 2020 22:34:58 -0700 In-Reply-To: <20200515053500.215929-1-saravanak@google.com> Message-Id: <20200515053500.215929-3-saravanak@google.com> Mime-Version: 1.0 References: <20200515053500.215929-1-saravanak@google.com> X-Mailer: git-send-email 2.26.2.761.g0e0b3e54be-goog Subject: [PATCH v1 2/4] driver core: Look for waiting consumers only for a fwnode's primary device From: Saravana Kannan To: Greg Kroah-Hartman , "Rafael J. Wysocki" , Rob Herring , Frank Rowand , Len Brown Cc: Saravana Kannan , kernel-team@android.com, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-acpi@vger.kernel.org, Ji Luo Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Commit 4dbe191c046e ("driver core: Add device links from fwnode only for the primary device") skipped linking a fwnode's secondary device to the suppliers listed in its fwnode. However, a fwnode's secondary device can't be found using get_dev_from_fwnode(). So, there's no point in trying to see if devices waiting for suppliers might want to link to a fwnode's secondary device. This commit removes that unnecessary step for devices that aren't a fwnode's primary device and also moves the code to a more appropriate part of the file. Signed-off-by: Saravana Kannan --- drivers/base/core.c | 29 ++++++++++++++++++----------- 1 file changed, 18 insertions(+), 11 deletions(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index 2b454aae64b5..f585d92e09d0 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -1173,6 +1173,21 @@ static bool fw_devlink_is_permissive(void) return fw_devlink_flags == DL_FLAG_SYNC_STATE_ONLY; } +static void fw_devlink_link_device(struct device *dev) +{ + int fw_ret; + + device_link_add_missing_supplier_links(); + + if (fw_devlink_flags && fwnode_has_op(dev->fwnode, add_links)) { + fw_ret = fwnode_call_int_op(dev->fwnode, add_links, dev); + if (fw_ret == -ENODEV && !fw_devlink_is_permissive()) + device_link_wait_for_mandatory_supplier(dev); + else if (fw_ret) + device_link_wait_for_optional_supplier(dev); + } +} + /* Device links support end. */ int (*platform_notify)(struct device *dev) = NULL; @@ -2407,7 +2422,7 @@ int device_add(struct device *dev) struct device *parent; struct kobject *kobj; struct class_interface *class_intf; - int error = -EINVAL, fw_ret; + int error = -EINVAL; struct kobject *glue_dir = NULL; bool is_fwnode_dev = false; @@ -2524,16 +2539,8 @@ int device_add(struct device *dev) * waiting consumers can link to it before the driver is bound to the * device and the driver sync_state callback is called for this device. */ - device_link_add_missing_supplier_links(); - - if (fw_devlink_flags && is_fwnode_dev && - fwnode_has_op(dev->fwnode, add_links)) { - fw_ret = fwnode_call_int_op(dev->fwnode, add_links, dev); - if (fw_ret == -ENODEV && !fw_devlink_is_permissive()) - device_link_wait_for_mandatory_supplier(dev); - else if (fw_ret) - device_link_wait_for_optional_supplier(dev); - } + if (is_fwnode_dev) + fw_devlink_link_device(dev); bus_probe_device(dev); if (parent) From patchwork Fri May 15 05:34:59 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Saravana Kannan X-Patchwork-Id: 194192 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.4 required=3.0 tests=DKIMWL_WL_MED, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 12526C433E1 for ; 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Thu, 14 May 2020 22:35:11 -0700 (PDT) Date: Thu, 14 May 2020 22:34:59 -0700 In-Reply-To: <20200515053500.215929-1-saravanak@google.com> Message-Id: <20200515053500.215929-4-saravanak@google.com> Mime-Version: 1.0 References: <20200515053500.215929-1-saravanak@google.com> X-Mailer: git-send-email 2.26.2.761.g0e0b3e54be-goog Subject: [PATCH v1 3/4] driver core: fw_devlink: Add support for batching fwnode parsing From: Saravana Kannan To: Greg Kroah-Hartman , "Rafael J. Wysocki" , Rob Herring , Frank Rowand , Len Brown Cc: Saravana Kannan , kernel-team@android.com, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-acpi@vger.kernel.org, Ji Luo Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org The amount of time spent parsing fwnodes of devices can become really high if the devices are added in an non-ideal order. Worst case can be O(N^2) when N devices are added. But this can be optimized to O(N) by adding all the devices and then parsing all their fwnodes in one batch. This commit adds fw_devlink_pause() and fw_devlink_resume() to allow doing this. Signed-off-by: Saravana Kannan --- drivers/base/base.h | 1 + drivers/base/core.c | 116 ++++++++++++++++++++++++++++++++++++++--- drivers/base/dd.c | 8 +++ include/linux/fwnode.h | 2 + 4 files changed, 120 insertions(+), 7 deletions(-) diff --git a/drivers/base/base.h b/drivers/base/base.h index 40fb069a8a7e..95c22c0f9036 100644 --- a/drivers/base/base.h +++ b/drivers/base/base.h @@ -153,6 +153,7 @@ extern char *make_class_name(const char *name, struct kobject *kobj); extern int devres_release_all(struct device *dev); extern void device_block_probing(void); extern void device_unblock_probing(void); +extern void driver_deferred_probe_force_trigger(void); /* /sys/devices directory */ extern struct kset *devices_kset; diff --git a/drivers/base/core.c b/drivers/base/core.c index f585d92e09d0..84c569726d75 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -49,6 +49,9 @@ static LIST_HEAD(wait_for_suppliers); static DEFINE_MUTEX(wfs_lock); static LIST_HEAD(deferred_sync); static unsigned int defer_sync_state_count = 1; +static unsigned int defer_fw_devlink_count; +static DEFINE_MUTEX(defer_fw_devlink_lock); +static bool fw_devlink_is_permissive(void); #ifdef CONFIG_SRCU static DEFINE_MUTEX(device_links_lock); @@ -527,7 +530,7 @@ static void device_link_add_missing_supplier_links(void) int ret = fwnode_call_int_op(dev->fwnode, add_links, dev); if (!ret) list_del_init(&dev->links.needs_suppliers); - else if (ret != -ENODEV) + else if (ret != -ENODEV || fw_devlink_is_permissive()) dev->links.need_for_probe = false; } mutex_unlock(&wfs_lock); @@ -1177,17 +1180,116 @@ static void fw_devlink_link_device(struct device *dev) { int fw_ret; - device_link_add_missing_supplier_links(); + if (!fw_devlink_flags) + return; + + mutex_lock(&defer_fw_devlink_lock); + if (!defer_fw_devlink_count) + device_link_add_missing_supplier_links(); + + /* + * The device's fwnode not having add_links() doesn't affect if other + * consumers can find this device as a supplier. So, this check is + * intentionally placed after device_link_add_missing_supplier_links(). + */ + if (!fwnode_has_op(dev->fwnode, add_links)) + goto out; - if (fw_devlink_flags && fwnode_has_op(dev->fwnode, add_links)) { + /* + * If fw_devlink is being deferred, assume all devices have mandatory + * suppliers they need to link to later. Then, when the fw_devlink is + * resumed, all these devices will get a chance to try and link to any + * suppliers they have. + */ + if (!defer_fw_devlink_count) { fw_ret = fwnode_call_int_op(dev->fwnode, add_links, dev); - if (fw_ret == -ENODEV && !fw_devlink_is_permissive()) - device_link_wait_for_mandatory_supplier(dev); - else if (fw_ret) - device_link_wait_for_optional_supplier(dev); + if (fw_ret == -ENODEV && fw_devlink_is_permissive()) + fw_ret = -EAGAIN; + } else { + fw_ret = -ENODEV; } + + if (fw_ret == -ENODEV) + device_link_wait_for_mandatory_supplier(dev); + else if (fw_ret) + device_link_wait_for_optional_supplier(dev); + +out: + mutex_unlock(&defer_fw_devlink_lock); } +/** + * fw_devlink_pause - Pause parsing of fwnode to create device links + * + * Calling this function defers any fwnode parsing to create device links until + * fw_devlink_resume() is called. Both these functions are ref counted and the + * caller needs to match the calls. + * + * While fw_devlink is paused: + * - Any device that is added won't have its fwnode parsed to create device + * links. + * - The probe of the device will also be deferred during this period. + * - Any devices that were already added, but waiting for suppliers won't be + * able to link to newly added devices. + * + * Once fw_devlink_resume(): + * - All the fwnodes that was not parsed will be parsed. + * - All the devices that were deferred probing will be reattempted if they + * aren't waiting for any more suppliers. + * + * This pair of functions, is mainly meant to optimize the parsing of fwnodes + * when a lot of devices that need to link to each other are added in a short + * interval of time. For example, adding all the top level devices in a system. + * + * For example, if N devices are added and: + * - All the consumers are added before their suppliers + * - All the suppliers of the N devices are part of the N devices + * + * Then: + * + * - With the use of fw_devlink_pause() and fw_devlink_resume(), each device + * will only need one parsing of its fwnode because it is guaranteed to find + * all the supplier devices already registered and ready to link to. It won't + * have to do another pass later to find one or more suppliers it couldn't + * find in the first parse of the fwnode. So, we'll only need O(N) fwnode + * parses. + * + * - Without the use of fw_devlink_pause() and fw_devlink_resume(), we would + * end up doing O(N^2) parses of fwnodes because every device that's added is + * guaranteed to trigger a parse of the fwnode of every device added before + * it. This O(N^2) parse is made worse by the fact that when a fwnode of a + * device is parsed, all it descendant devices might need to have their + * fwnodes parsed too (even if the devices themselves aren't added). + */ +void fw_devlink_pause(void) +{ + mutex_lock(&defer_fw_devlink_lock); + defer_fw_devlink_count++; + mutex_unlock(&defer_fw_devlink_lock); +} + +/** fw_devlink_resume - Resume parsing of fwnode to create device links + * + * This function is used in conjunction with fw_devlink_pause() and is ref + * counted. See documentation for fw_devlink_pause() for more details. + */ +void fw_devlink_resume(void) +{ + mutex_lock(&defer_fw_devlink_lock); + if (!defer_fw_devlink_count) { + WARN(true, "Unmatched fw_devlink pause/resume!"); + goto out; + } + + defer_fw_devlink_count--; + if (defer_fw_devlink_count) + goto out; + + device_link_add_missing_supplier_links(); + driver_deferred_probe_force_trigger(); +out: + mutex_unlock(&defer_fw_devlink_lock); +} /* Device links support end. */ int (*platform_notify)(struct device *dev) = NULL; diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 48ca81cb8ebc..63991d97adcc 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -160,6 +160,14 @@ static bool driver_deferred_probe_enable = false; * again. */ static void driver_deferred_probe_trigger(void) +{ + if (!driver_deferred_probe_enable) + return; + + driver_deferred_probe_force_trigger(); +} + +void driver_deferred_probe_force_trigger(void) { if (!driver_deferred_probe_enable) return; diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h index e0abafbb17f8..9506f8ec0974 100644 --- a/include/linux/fwnode.h +++ b/include/linux/fwnode.h @@ -171,5 +171,7 @@ struct fwnode_operations { #define get_dev_from_fwnode(fwnode) get_device((fwnode)->dev) extern u32 fw_devlink_get_flags(void); +void fw_devlink_pause(void); +void fw_devlink_resume(void); #endif