From 1ddc7618294084fff8d673217a9479550990ee84 Mon Sep 17 00:00:00 2001 From: Manivannan Sadhasivam Date: Mon, 23 Jan 2023 12:59:45 +0530 Subject: bus: mhi: ep: Change state_lock to mutex 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 Reviewed-by: Jeffrey Hugo Signed-off-by: Manivannan Sadhasivam --- drivers/bus/mhi/ep/main.c | 8 +++++--- drivers/bus/mhi/ep/sm.c | 42 ++++++++++++++++++++++++------------------ 2 files changed, 29 insertions(+), 21 deletions(-) (limited to 'drivers/bus') 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; } -- cgit v1.2.3