1. We need a write lock in mhi_gen_tre otherwise there is race of the WP
used for ringing channel DB between mhi_queue and M0 transition.
2. We can not invoke local_bh_enable() when irqs are disabled, so move
read_lock_irqsave() under the mhi_gen_tre() since we add write_lock_bh() in
mhi_gen_tre().
3. Unlock xfer_cb to prevent potential lockup
4. After re-lock, check mhi channel state again to stop processing of a
disabled or stopped channel.
v1 -> v2:
Added write_unlock_bh(&mhi_chan->lock) in mhi_gen_tre() before return
because of error process.
v2 -> v3:
1. split protecting WP and unlocking xfer_cb into two patches
2. Add a new patch to stop processing buffer and eventof a disabled or
stopped channel.
Bhaumik Bhatt (1):
bus: mhi: host: Add spinlock to protect WP access when queueing TREs
Hemant Kumar (1):
bus: mhi: host: Take irqsave lock after TRE is generated
Qiang Yu (2):
bus: mhi: host: Drop chan lock before queuing buffers
bus: mhi: host: Avoid processing buffer and event of a disable channel
drivers/bus/mhi/host/main.c | 30 +++++++++++++++++++++---------
1 file changed, 21 insertions(+), 9 deletions(-)
--
2.7.4
Ckeck mhi channel state after getting chan->lock to ensure that we only
queue buffer to an enabled channel and process event of an enabled channel.
Signed-off-by: Qiang Yu <[email protected]>
---
drivers/bus/mhi/host/main.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c
index a236dc2..b137d54 100644
--- a/drivers/bus/mhi/host/main.c
+++ b/drivers/bus/mhi/host/main.c
@@ -672,6 +672,8 @@ static int parse_xfer_event(struct mhi_controller *mhi_cntrl,
}
read_lock_bh(&mhi_chan->lock);
+ if (mhi_chan->ch_state != MHI_CH_STATE_ENABLED)
+ goto end_process_tx_event;
}
break;
} /* CC_EOT */
@@ -1211,6 +1213,8 @@ int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan,
/* Protect accesses for reading and incrementing WP */
write_lock_bh(&mhi_chan->lock);
+ if (mhi_chan->ch_state != MHI_CH_STATE_ENABLED)
+ return -EINVAL;
buf_ring = &mhi_chan->buf_ring;
tre_ring = &mhi_chan->tre_ring;
--
2.7.4
From: Hemant Kumar <[email protected]>
Take irqsave lock after TRE is generated to avoid deadlock due to core
getting interrupts enabled as local_bh_enable must not be called with
irqs disabled based on upstream patch.
Signed-off-by: Hemant Kumar <[email protected]>
Signed-off-by: Lazarus Motha <[email protected]>
Signed-off-by: Qiang Yu <[email protected]>
---
drivers/bus/mhi/host/main.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c
index b137d54..93b5110 100644
--- a/drivers/bus/mhi/host/main.c
+++ b/drivers/bus/mhi/host/main.c
@@ -1129,17 +1129,15 @@ static int mhi_queue(struct mhi_device *mhi_dev, struct mhi_buf_info *buf_info,
if (unlikely(MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)))
return -EIO;
- read_lock_irqsave(&mhi_cntrl->pm_lock, flags);
-
ret = mhi_is_ring_full(mhi_cntrl, tre_ring);
- if (unlikely(ret)) {
- ret = -EAGAIN;
- goto exit_unlock;
- }
+ if (unlikely(ret))
+ return -EAGAIN;
ret = mhi_gen_tre(mhi_cntrl, mhi_chan, buf_info, mflags);
if (unlikely(ret))
- goto exit_unlock;
+ return ret;
+
+ read_lock_irqsave(&mhi_cntrl->pm_lock, flags);
/* Packet is queued, take a usage ref to exit M3 if necessary
* for host->device buffer, balanced put is done on buffer completion
@@ -1159,7 +1157,6 @@ static int mhi_queue(struct mhi_device *mhi_dev, struct mhi_buf_info *buf_info,
if (dir == DMA_FROM_DEVICE)
mhi_cntrl->runtime_put(mhi_cntrl);
-exit_unlock:
read_unlock_irqrestore(&mhi_cntrl->pm_lock, flags);
return ret;
--
2.7.4
From: Bhaumik Bhatt <[email protected]>
Protect WP accesses such that multiple threads queueing buffers for
incoming data do not race.
Cc: <[email protected]>
Fixes: 189ff97cca53 ("bus: mhi: core: Add support for data transfer")
Signed-off-by: Bhaumik Bhatt <[email protected]>
Signed-off-by: Qiang Yu <[email protected]>
---
drivers/bus/mhi/host/main.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c
index 6cf1145..c9415b0 100644
--- a/drivers/bus/mhi/host/main.c
+++ b/drivers/bus/mhi/host/main.c
@@ -1205,6 +1205,9 @@ int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan,
int eot, eob, chain, bei;
int ret;
+ /* Protect accesses for reading and incrementing WP */
+ write_lock_bh(&mhi_chan->lock);
+
buf_ring = &mhi_chan->buf_ring;
tre_ring = &mhi_chan->tre_ring;
@@ -1222,8 +1225,10 @@ int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan,
if (!info->pre_mapped) {
ret = mhi_cntrl->map_single(mhi_cntrl, buf_info);
- if (ret)
+ if (ret) {
+ write_unlock_bh(&mhi_chan->lock);
return ret;
+ }
}
eob = !!(flags & MHI_EOB);
@@ -1240,6 +1245,8 @@ int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan,
mhi_add_ring_element(mhi_cntrl, tre_ring);
mhi_add_ring_element(mhi_cntrl, buf_ring);
+ write_unlock_bh(&mhi_chan->lock);
+
return 0;
}
--
2.7.4