From patchwork Wed Jun 16 10:36:47 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Wiklander X-Patchwork-Id: 461564 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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT 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 D19AAC49EA6 for ; Wed, 16 Jun 2021 10:37:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BB71361164 for ; Wed, 16 Jun 2021 10:37:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232430AbhFPKjb (ORCPT ); Wed, 16 Jun 2021 06:39:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57022 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232462AbhFPKjZ (ORCPT ); Wed, 16 Jun 2021 06:39:25 -0400 Received: from mail-lf1-x129.google.com (mail-lf1-x129.google.com [IPv6:2a00:1450:4864:20::129]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0A458C061226 for ; Wed, 16 Jun 2021 03:37:15 -0700 (PDT) Received: by mail-lf1-x129.google.com with SMTP id f30so3557956lfj.1 for ; Wed, 16 Jun 2021 03:37:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=nE0O5cQU8hO3PBDLKhrY8XOB0KUsBuVPprzerF6bl2k=; b=k16li5nOZGgYY0nec0s+jmVsg38V+i0m8AtY6nYedCt27GjPhEsBpnVbd9cbUDHXcX RgX6oEC4IuT9Rgr3PuKZNLnxbGM6FxMxao0YZ/fUkR21YsElDbdQat2DKYAH3abWsIuM aDM26qrvxIYFyR24WBmg7RMTl6CtQY/aIGnViMFbjYPK6Q7vlfInTOg2AZ0MtSzSHPYB s7rQvHakK/3luLxJshDNc+SP7AlT1iFj14HqUoszeAWZJEgGE06H7NDjNuuH/9oXomTA mCxYwXXCGq/q/ZlU5zG9OKEK/oQpUpvGcKaJrdu5T6T+b2kyqAZu+W6zdkkCdMHCr/v2 iDyg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=nE0O5cQU8hO3PBDLKhrY8XOB0KUsBuVPprzerF6bl2k=; b=roYBHP8IB7k3sYi0f7XqhRfzRKyTRxcuQBTWGH6rBnhSACEgS8njZQABUbLKyaGNJB bfESIScnQBgeqj1G1qxbLHM+/pORrEDBiINp0+L0eprTxUzDNzU6vf66lGAVRLdySstx cJcZwJ3ev5xi+AugGC2T0qGcM/7RhXEoYLVaxMX1QPVLqqu2OOtHKbJWnO5lik0HYdiU Qb3+jZ7gK16goxQj5ZZWONpxTaaesRxUR1hpV5wEMkvk00noPXW9UQSG6fNdz2D+yUbW yacDRE+HMx6ibP/M3sfQ0BOvwTlmi4emGC1TcwfBmJWNAULGsok1d1rUePWU+xhoZQwh HTBQ== X-Gm-Message-State: AOAM533MI/UGDJRf4ZwoZ7B4D+XO4KxjkyDUke395o4bdARJslZRkp/h b4PVt7ukLXMzpw4XV6V2nMBycA== X-Google-Smtp-Source: ABdhPJxlGQxPkzYmAgnMySBW3P/4sn8vf4auEa0rSVlvSI7dwnCv9fks3Osl+2ntItuO2whQVGbO5g== X-Received: by 2002:a19:7711:: with SMTP id s17mr3308348lfc.430.1623839833963; Wed, 16 Jun 2021 03:37:13 -0700 (PDT) Received: from jade.urgonet (h-79-136-85-3.A175.priv.bahnhof.se. [79.136.85.3]) by smtp.gmail.com with ESMTPSA id m17sm205621lfh.288.2021.06.16.03.37.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Jun 2021 03:37:13 -0700 (PDT) From: Jens Wiklander To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, op-tee@lists.trustedfirmware.org, devicetree@vger.kernel.org, linux-doc@vger.kernel.org Cc: Jerome Forissier , Etienne Carriere , Sumit Garg , Vincent Guittot , Rob Herring , Jonathan Corbet , Ard Biesheuvel , Marc Zyngier , Jens Wiklander Subject: [PATCH v2 5/7] tee: add tee_dev_open_helper() primitive Date: Wed, 16 Jun 2021 12:36:47 +0200 Message-Id: <20210616103649.2662395-6-jens.wiklander@linaro.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210616103649.2662395-1-jens.wiklander@linaro.org> References: <20210616103649.2662395-1-jens.wiklander@linaro.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Adds tee_dev_open_helper() and tee_dev_ctx_put() to make it easier to create a driver internal struct tee_context without the usual tee_device_get() on the struct tee_device as that adds a circular reference counter dependency and would prevent the struct tee_device from ever being released again. Signed-off-by: Jens Wiklander --- drivers/tee/tee_core.c | 33 ++++++++++++++++++++++++--------- include/linux/tee_drv.h | 27 +++++++++++++++++++++++++++ 2 files changed, 51 insertions(+), 9 deletions(-) diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c index f97d95b50773..6d81f6268b99 100644 --- a/drivers/tee/tee_core.c +++ b/drivers/tee/tee_core.c @@ -43,14 +43,11 @@ static DEFINE_SPINLOCK(driver_lock); static struct class *tee_class; static dev_t tee_devt; -static struct tee_context *teedev_open(struct tee_device *teedev) +struct tee_context *tee_dev_open_helper(struct tee_device *teedev) { int rc; struct tee_context *ctx; - if (!tee_device_get(teedev)) - return ERR_PTR(-EINVAL); - ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); if (!ctx) { rc = -ENOMEM; @@ -66,10 +63,30 @@ static struct tee_context *teedev_open(struct tee_device *teedev) return ctx; err: kfree(ctx); - tee_device_put(teedev); return ERR_PTR(rc); } +EXPORT_SYMBOL_GPL(tee_dev_open_helper); + +void tee_dev_ctx_put(struct tee_context *ctx) +{ + teedev_ctx_put(ctx); +} +EXPORT_SYMBOL_GPL(tee_dev_ctx_put); + +static struct tee_context *teedev_open(struct tee_device *teedev) +{ + struct tee_context *ctx; + + if (!tee_device_get(teedev)) + return ERR_PTR(-EINVAL); + + ctx = tee_dev_open_helper(teedev); + if (IS_ERR(ctx)) + tee_device_put(teedev); + + return ctx; +} void teedev_ctx_get(struct tee_context *ctx) { @@ -90,10 +107,8 @@ static void teedev_ctx_release(struct kref *ref) void teedev_ctx_put(struct tee_context *ctx) { - if (ctx->releasing) - return; - - kref_put(&ctx->refcount, teedev_ctx_release); + if (ctx && !ctx->releasing) + kref_put(&ctx->refcount, teedev_ctx_release); } static void teedev_close_context(struct tee_context *ctx) diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h index 54269e47ac9a..f592ba4e9561 100644 --- a/include/linux/tee_drv.h +++ b/include/linux/tee_drv.h @@ -456,6 +456,33 @@ static inline int tee_shm_get_id(struct tee_shm *shm) */ struct tee_shm *tee_shm_get_from_id(struct tee_context *ctx, int id); +/** + * tee_dev_open_helper() - helper function to make a struct tee_context + * @teedev: Device to open + * + * Creates the struct tee_context without increasing the reference counter + * on @teedev. This is needed for instance when a driver need an internal + * struct tee_context to operate on. By skipping the reference counter + * the circular dependency is broken. + * + * Note that this struct tee_context need special care when freeing in + * order to avoid the normal put on the struct tee_device. + * tee_dev_ctx_put() is the best choice for this. + * + * @returns a pointer 'struct tee_context' on success or an ERR_PTR on failure + */ +struct tee_context *tee_dev_open_helper(struct tee_device *teedev); + +/** + * tee_dev_ctx_put() - helper function to release a struct tee_context + * @ctx: The struct tee_context to release + * + * Note that this function doesn't do a tee_device_put() on the internal + * struct tee_device so this function should normal only be used when + * releasing a struct tee_context obtained with tee_dev_open_helper(). + */ +void tee_dev_ctx_put(struct tee_context *ctx); + /** * tee_client_open_context() - Open a TEE context * @start: if not NULL, continue search after this context