From patchwork Mon Jan 23 07:50:49 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Manivannan Sadhasivam X-Patchwork-Id: 645640 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 665F2C05027 for ; Mon, 23 Jan 2023 07:51:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231268AbjAWHvI (ORCPT ); Mon, 23 Jan 2023 02:51:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38542 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229989AbjAWHvH (ORCPT ); Mon, 23 Jan 2023 02:51:07 -0500 Received: from mail-pj1-x102f.google.com (mail-pj1-x102f.google.com [IPv6:2607:f8b0:4864:20::102f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 03BE5EB61 for ; Sun, 22 Jan 2023 23:51:03 -0800 (PST) Received: by mail-pj1-x102f.google.com with SMTP id o13so10917077pjg.2 for ; Sun, 22 Jan 2023 23:51:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=tO+IyOnJfDPFLFS1K1GLxKTMhSkraFKNnAGsYcCy4Cs=; b=AtGDoqw8G39Pb3dQjkkl9jfAs08uIlMvFO7gGtEFi6PWt/X5A6ltQ6pYsfrNcdrMJp zwWX8s/+Jc347dGkvnVFh30USmH3SKeKJlsUC+W9Z82dMexGvGlorfmxenVlmeficqX0 wd03r4O8udsc9PLBKFQZ9DsDVXm+WktnwIOYMUT2WOgXRc6/aodMmlywNeAuMnsXj8Lh a/DiifGRS9t+Wu76hOaMHV4UjwNabBhYl3q8uOfuHviNkbd8ryN7V2M9OFr//kJqKNU8 LC/Cs5QACM6Vzaif5L5bN51YCb3n91uzpHsoqjplp8RaofYbOgPcDBOFYzJAaPzhQCjE uOxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=tO+IyOnJfDPFLFS1K1GLxKTMhSkraFKNnAGsYcCy4Cs=; b=yW9wbQKarvdB0uDJ8SEfBboo3mqns4KrMJdifCr+/vI0URqsAcj0w2N1ibEn1X7m/N aE3eTFY78BFxaqflPMgYBIlkZYJHSc8nX+rmX+qoJsqZuJ1yHiPacD4PwWPqVd42VJur nFcegovXbklK3Ftum+1kT8na5An3z4mCnCqDlXmyh4VOD35bX/iDCY+j10JxwqIkX9QT 3piirrieq8SbBx+UgFgTJckzKSrom2DgYHa9heGd4qc2fQV6sdTztihKU1gKGvFATWAQ iiN/FCgQNO5yWKaKpfRkC5clDoUigu+hk54HTcAraiCIkdd250hVad6Jr4I94qiEIEFq bxeQ== X-Gm-Message-State: AFqh2kpvh2PYIkJRxcMMWxjC/nBd+v5qW+78kCfUH5uO0O1LRRU7X5Oa cOm/xJW5MrfUJjL/r9OF/vMv X-Google-Smtp-Source: AMrXdXuQSvipdphA5iwXPzdaZoJlrdZ1d5r1RLxKU20QvrLH+MR4/RmknzGoZfLAnQ89NLupF4FFog== X-Received: by 2002:a17:903:244f:b0:194:6400:cd37 with SMTP id l15-20020a170903244f00b001946400cd37mr33549307pls.14.1674460262495; Sun, 22 Jan 2023 23:51:02 -0800 (PST) Received: from localhost.localdomain ([117.193.209.99]) by smtp.gmail.com with ESMTPSA id v3-20020a170902e8c300b0019602274208sm2123454plg.186.2023.01.22.23.50.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 22 Jan 2023 23:51:01 -0800 (PST) From: Manivannan Sadhasivam To: mhi@lists.linux.dev Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, Manivannan Sadhasivam , stable@vger.kernel.org, Dan Carpenter Subject: [PATCH] bus: mhi: ep: Change state_lock to mutex Date: Mon, 23 Jan 2023 13:20:49 +0530 Message-Id: <20230123075049.168040-1-manivannan.sadhasivam@linaro.org> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org state_lock, the spinlock type is meant to protect race against concurrent MHI state transitions. In mhi_ep_set_m0_state(), while the state_lock is being held, the channels are resumed in mhi_ep_resume_channels() if the previous state was M3. This causes sleeping in atomic bug, since mhi_ep_resume_channels() use mutex internally. Since the state_lock is supposed to be held throughout the state change, it is not ideal to drop the lock before calling mhi_ep_resume_channels(). So to fix this issue, let's change the type of state_lock to mutex. This would also allow holding the lock throughout all state transitions thereby avoiding any potential race. Cc: # 5.19 Fixes: e4b7b5f0f30a ("bus: mhi: ep: Add support for suspending and resuming channels") Reported-by: Dan Carpenter Signed-off-by: Manivannan Sadhasivam --- drivers/bus/mhi/ep/main.c | 8 +++++--- drivers/bus/mhi/ep/sm.c | 42 ++++++++++++++++++++++----------------- include/linux/mhi_ep.h | 4 ++-- 3 files changed, 31 insertions(+), 23 deletions(-) diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c index bcaaba97ef63..528c00b232bf 100644 --- a/drivers/bus/mhi/ep/main.c +++ b/drivers/bus/mhi/ep/main.c @@ -1001,11 +1001,11 @@ static void mhi_ep_reset_worker(struct work_struct *work) mhi_ep_power_down(mhi_cntrl); - spin_lock_bh(&mhi_cntrl->state_lock); + mutex_lock(&mhi_cntrl->state_lock); + /* Reset MMIO to signal host that the MHI_RESET is completed in endpoint */ mhi_ep_mmio_reset(mhi_cntrl); cur_state = mhi_cntrl->mhi_state; - spin_unlock_bh(&mhi_cntrl->state_lock); /* * Only proceed further if the reset is due to SYS_ERR. The host will @@ -1014,6 +1014,8 @@ static void mhi_ep_reset_worker(struct work_struct *work) */ if (cur_state == MHI_STATE_SYS_ERR) mhi_ep_power_up(mhi_cntrl); + + mutex_unlock(&mhi_cntrl->state_lock); } /* @@ -1386,8 +1388,8 @@ int mhi_ep_register_controller(struct mhi_ep_cntrl *mhi_cntrl, INIT_LIST_HEAD(&mhi_cntrl->st_transition_list); INIT_LIST_HEAD(&mhi_cntrl->ch_db_list); - spin_lock_init(&mhi_cntrl->state_lock); spin_lock_init(&mhi_cntrl->list_lock); + mutex_init(&mhi_cntrl->state_lock); mutex_init(&mhi_cntrl->event_lock); /* Set MHI version and AMSS EE before enumeration */ diff --git a/drivers/bus/mhi/ep/sm.c b/drivers/bus/mhi/ep/sm.c index 3655c19e23c7..fd200b2ac0bb 100644 --- a/drivers/bus/mhi/ep/sm.c +++ b/drivers/bus/mhi/ep/sm.c @@ -63,24 +63,23 @@ int mhi_ep_set_m0_state(struct mhi_ep_cntrl *mhi_cntrl) int ret; /* If MHI is in M3, resume suspended channels */ - spin_lock_bh(&mhi_cntrl->state_lock); + mutex_lock(&mhi_cntrl->state_lock); + old_state = mhi_cntrl->mhi_state; if (old_state == MHI_STATE_M3) mhi_ep_resume_channels(mhi_cntrl); ret = mhi_ep_set_mhi_state(mhi_cntrl, MHI_STATE_M0); - spin_unlock_bh(&mhi_cntrl->state_lock); - if (ret) { mhi_ep_handle_syserr(mhi_cntrl); - return ret; + goto err_unlock; } /* Signal host that the device moved to M0 */ ret = mhi_ep_send_state_change_event(mhi_cntrl, MHI_STATE_M0); if (ret) { dev_err(dev, "Failed sending M0 state change event\n"); - return ret; + goto err_unlock; } if (old_state == MHI_STATE_READY) { @@ -88,11 +87,14 @@ int mhi_ep_set_m0_state(struct mhi_ep_cntrl *mhi_cntrl) ret = mhi_ep_send_ee_event(mhi_cntrl, MHI_EE_AMSS); if (ret) { dev_err(dev, "Failed sending AMSS EE event\n"); - return ret; + goto err_unlock; } } - return 0; +err_unlock: + mutex_unlock(&mhi_cntrl->state_lock); + + return ret; } int mhi_ep_set_m3_state(struct mhi_ep_cntrl *mhi_cntrl) @@ -100,13 +102,12 @@ int mhi_ep_set_m3_state(struct mhi_ep_cntrl *mhi_cntrl) struct device *dev = &mhi_cntrl->mhi_dev->dev; int ret; - spin_lock_bh(&mhi_cntrl->state_lock); - ret = mhi_ep_set_mhi_state(mhi_cntrl, MHI_STATE_M3); - spin_unlock_bh(&mhi_cntrl->state_lock); + mutex_lock(&mhi_cntrl->state_lock); + ret = mhi_ep_set_mhi_state(mhi_cntrl, MHI_STATE_M3); if (ret) { mhi_ep_handle_syserr(mhi_cntrl); - return ret; + goto err_unlock; } mhi_ep_suspend_channels(mhi_cntrl); @@ -115,10 +116,13 @@ int mhi_ep_set_m3_state(struct mhi_ep_cntrl *mhi_cntrl) ret = mhi_ep_send_state_change_event(mhi_cntrl, MHI_STATE_M3); if (ret) { dev_err(dev, "Failed sending M3 state change event\n"); - return ret; + goto err_unlock; } - return 0; +err_unlock: + mutex_unlock(&mhi_cntrl->state_lock); + + return ret; } int mhi_ep_set_ready_state(struct mhi_ep_cntrl *mhi_cntrl) @@ -127,22 +131,24 @@ int mhi_ep_set_ready_state(struct mhi_ep_cntrl *mhi_cntrl) enum mhi_state mhi_state; int ret, is_ready; - spin_lock_bh(&mhi_cntrl->state_lock); + mutex_lock(&mhi_cntrl->state_lock); + /* Ensure that the MHISTATUS is set to RESET by host */ mhi_state = mhi_ep_mmio_masked_read(mhi_cntrl, EP_MHISTATUS, MHISTATUS_MHISTATE_MASK); is_ready = mhi_ep_mmio_masked_read(mhi_cntrl, EP_MHISTATUS, MHISTATUS_READY_MASK); if (mhi_state != MHI_STATE_RESET || is_ready) { dev_err(dev, "READY state transition failed. MHI host not in RESET state\n"); - spin_unlock_bh(&mhi_cntrl->state_lock); - return -EIO; + ret = -EIO; + goto err_unlock; } ret = mhi_ep_set_mhi_state(mhi_cntrl, MHI_STATE_READY); - spin_unlock_bh(&mhi_cntrl->state_lock); - if (ret) mhi_ep_handle_syserr(mhi_cntrl); +err_unlock: + mutex_unlock(&mhi_cntrl->state_lock); + return ret; } diff --git a/include/linux/mhi_ep.h b/include/linux/mhi_ep.h index 478aece17046..f198a8ac7ee7 100644 --- a/include/linux/mhi_ep.h +++ b/include/linux/mhi_ep.h @@ -70,8 +70,8 @@ struct mhi_ep_db_info { * @cmd_ctx_cache_phys: Physical address of the host command context cache * @chdb: Array of channel doorbell interrupt info * @event_lock: Lock for protecting event rings - * @list_lock: Lock for protecting state transition and channel doorbell lists * @state_lock: Lock for protecting state transitions + * @list_lock: Lock for protecting state transition and channel doorbell lists * @st_transition_list: List of state transitions * @ch_db_list: List of queued channel doorbells * @wq: Dedicated workqueue for handling rings and state changes @@ -117,8 +117,8 @@ struct mhi_ep_cntrl { struct mhi_ep_db_info chdb[4]; struct mutex event_lock; + struct mutex state_lock; spinlock_t list_lock; - spinlock_t state_lock; struct list_head st_transition_list; struct list_head ch_db_list;