ath10k_hw_qca988x_set_coverage_class needs to hold both conf_mutex and
the data_lock spin lock for parts of the function. However, data_lock
is only needed while storing the coverage_class to store the value that
the card is configured to.

Fix the locking issue by only holding data_lock for the required duration.

Signed-off-by: Benjamin Berg <benja...@sipsolutions.net>
---

And yes, I fully agree with your points of it being rather fragile. But as
you said, it should be entirely safe if not used. Obviously a firmware
implementation would be preferential.

This locking issue was pretty unnecessary. Lets see if any more issues show
up in a closer review.

 drivers/net/wireless/ath/ath10k/core.h | 2 +-
 drivers/net/wireless/ath/ath10k/hw.c   | 5 +++--
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/ath/ath10k/core.h 
b/drivers/net/wireless/ath/ath10k/core.h
index 89b07be..5f8c31f 100644
--- a/drivers/net/wireless/ath/ath10k/core.h
+++ b/drivers/net/wireless/ath/ath10k/core.h
@@ -915,7 +915,7 @@ struct ath10k {
        struct work_struct set_coverage_class_work;
        /* protected by conf_mutex */
        struct {
-               /* protected by data_lock */
+               /* writing also protected by data_lock */
                s16 coverage_class;
 
                u32 reg_phyclk;
diff --git a/drivers/net/wireless/ath/ath10k/hw.c 
b/drivers/net/wireless/ath/ath10k/hw.c
index e182f09..bd5ca6a 100644
--- a/drivers/net/wireless/ath/ath10k/hw.c
+++ b/drivers/net/wireless/ath/ath10k/hw.c
@@ -243,7 +243,6 @@ static void ath10k_hw_qca988x_set_coverage_class(struct 
ath10k *ar,
        u32 fw_dbglog_level;
 
        mutex_lock(&ar->conf_mutex);
-       spin_lock_bh(&ar->data_lock);
 
        /* Only modify registers if the core is started. */
        if ((ar->state != ATH10K_STATE_ON) &&
@@ -356,12 +355,14 @@ static void ath10k_hw_qca988x_set_coverage_class(struct 
ath10k *ar,
 
 store_regs:
        /* After an error we will not retry setting the coverage class. */
+       spin_lock_bh(&ar->data_lock);
        ar->fw_coverage.coverage_class = value;
+       spin_unlock_bh(&ar->data_lock);
+
        ar->fw_coverage.reg_slottime_conf = slottime_reg;
        ar->fw_coverage.reg_ack_cts_timeout_conf = timeout_reg;
 
 unlock:
-       spin_unlock_bh(&ar->data_lock);
        mutex_unlock(&ar->conf_mutex);
 }
 
-- 
2.9.3


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