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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C83F1C77B7D for ; Wed, 17 May 2023 15:23:51 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A422010E44C; Wed, 17 May 2023 15:23:51 +0000 (UTC) Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by gabe.freedesktop.org (Postfix) with ESMTPS id 7779810E442 for ; Wed, 17 May 2023 15:23:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1684337027; x=1715873027; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=p9CsLEvbqkWlqRU3X0dbwGhR5hBs2hMcdyaSn9ApQAQ=; b=XayyxgdVqW45/EpyLcitscw7FXrHBhB4kET3r0S/ALpJRM1GC7DodqJf hgFQLt5yUT7tIwjAq2UnpfPe62Ywvpa004Otp6KaGiwXEAMZhSftz5XwE ky/Fip4S5fkNEU/O9dBCauond7CnrdFJzyfXZmxFNt4YWoompeVjaZcbY x18bDudcKVcxmPY17lGbpvmb0QYha9FZ2dcowF6rOxhRqQr+6qIWsBL5P +2VbLWHlOpFuJNti+jgjHJakdc0G9arRByZ+meDV4/eOS/Kvr0fO/SNYM Bv9bKQp3/Vw7e4bNdEDo9GdvT78YV6qoE+nznd6M/szDV/rpdYeKOB6Uj Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10713"; a="438132163" X-IronPort-AV: E=Sophos;i="5.99,282,1677571200"; d="scan'208";a="438132163" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 May 2023 08:23:47 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10713"; a="846129318" X-IronPort-AV: E=Sophos;i="5.99,282,1677571200"; d="scan'208";a="846129318" Received: from fskirtun-mobl-g8.ger.corp.intel.com (HELO mwauld-desk1.intel.com) ([10.252.15.194]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 May 2023 08:23:45 -0700 From: Matthew Auld To: intel-xe@lists.freedesktop.org Date: Wed, 17 May 2023 16:22:44 +0100 Message-Id: <20230517152244.348171-7-matthew.auld@intel.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230517152244.348171-1-matthew.auld@intel.com> References: <20230517152244.348171-1-matthew.auld@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: [Intel-xe] [PATCH v5 7/7] drm/xe: Use atomic for mem_access.ref X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Rodrigo Vivi Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" From: Maarten Lankhorst xe_guc_ct_fast_path() is called from an irq context, and cannot lock the mutex used by xe_device_mem_access_ongoing(). Fortunately it is easy to fix if we switch the ref over to an atomic. Signed-off-by: Maarten Lankhorst Signed-off-by: Matthew Auld Cc: Rodrigo Vivi Cc: Thomas Hellström Cc: Matthew Brost Reviewed-by: Rodrigo Vivi --- drivers/gpu/drm/xe/xe_device.c | 34 ++++++++++++---------------- drivers/gpu/drm/xe/xe_device_types.h | 4 ++-- 2 files changed, 17 insertions(+), 21 deletions(-) diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c index 55f974b1ee78..01ef88bf099d 100644 --- a/drivers/gpu/drm/xe/xe_device.c +++ b/drivers/gpu/drm/xe/xe_device.c @@ -403,30 +403,23 @@ u32 xe_device_ccs_bytes(struct xe_device *xe, u64 size) DIV_ROUND_UP(size, NUM_BYTES_PER_CCS_BYTE) : 0; } -void xe_device_assert_mem_access(struct xe_device *xe) -{ - if (xe_pm_read_callback_task(xe) == current) - return; - - XE_WARN_ON(!xe->mem_access.ref); -} - bool xe_device_mem_access_ongoing(struct xe_device *xe) { - bool ret; - if (xe_pm_read_callback_task(xe) == current) return true; - mutex_lock(&xe->mem_access.lock); - ret = xe->mem_access.ref; - mutex_unlock(&xe->mem_access.lock); + return atomic_read(&xe->mem_access.ref); +} - return ret; +void xe_device_assert_mem_access(struct xe_device *xe) +{ + XE_WARN_ON(!xe_device_mem_access_ongoing(xe)); } void xe_device_mem_access_get(struct xe_device *xe) { + int ref; + /* * This looks racy, but should be fine since the pm_callback_task only * transitions from NULL -> current (and back to NULL again), during the @@ -446,23 +439,26 @@ void xe_device_mem_access_get(struct xe_device *xe) * for example just on the 0 -> 1. */ mutex_lock(&xe->mem_access.lock); - if (xe->mem_access.ref == 0) + if (atomic_read(&xe->mem_access.ref) == 0) xe->mem_access.hold_rpm = xe_pm_runtime_resume_and_get(xe); - xe->mem_access.ref++; + ref = atomic_inc_return(&xe->mem_access.ref); mutex_unlock(&xe->mem_access.lock); - XE_WARN_ON(xe->mem_access.ref == S32_MAX); + XE_WARN_ON(ref == S32_MAX); } void xe_device_mem_access_put(struct xe_device *xe) { + int ref; + if (xe_pm_read_callback_task(xe) == current) return; mutex_lock(&xe->mem_access.lock); - if (--xe->mem_access.ref == 0 && xe->mem_access.hold_rpm) + ref = atomic_dec_return(&xe->mem_access.ref); + if (ref == 0 && xe->mem_access.hold_rpm) xe_pm_runtime_put(xe); mutex_unlock(&xe->mem_access.lock); - XE_WARN_ON(xe->mem_access.ref < 0); + XE_WARN_ON(ref < 0); } diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h index b0c69fcb4065..b3e96e48064a 100644 --- a/drivers/gpu/drm/xe/xe_device_types.h +++ b/drivers/gpu/drm/xe/xe_device_types.h @@ -258,11 +258,11 @@ struct xe_device { struct { /** * @lock: Serialize xe_device_mem_access users, - * and protect the below internal state, like @ref. + * and protect the below internal state. */ struct mutex lock; /** @ref: ref count of memory accesses */ - s32 ref; + atomic_t ref; /** @hold_rpm: need to put rpm ref back at the end */ bool hold_rpm; } mem_access; -- 2.40.1