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authorManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>2023-01-23 10:29:45 +0300
committerManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>2023-01-27 10:01:41 +0300
commit1ddc7618294084fff8d673217a9479550990ee84 (patch)
treea1c166517bd8d83b03148acd64d76d7d0cbf551a /drivers/bus
parent8a1c24bb908f9ecbc4be0fea014df67d43161551 (diff)
downloadlinux-1ddc7618294084fff8d673217a9479550990ee84.tar.xz
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: <stable@vger.kernel.org> # 5.19 Fixes: e4b7b5f0f30a ("bus: mhi: ep: Add support for suspending and resuming channels") Reported-by: Dan Carpenter <error27@gmail.com> Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Diffstat (limited to 'drivers/bus')
-rw-r--r--drivers/bus/mhi/ep/main.c8
-rw-r--r--drivers/bus/mhi/ep/sm.c42
2 files changed, 29 insertions, 21 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;
}