All of lore.kernel.org
 help / color / mirror / Atom feed
From: Benjamin Berg <benjamin@sipsolutions.net>
To: "Valo, Kalle" <kvalo@qca.qualcomm.com>
Cc: "ath10k @ lists . infradead . org" <ath10k@lists.infradead.org>,
	Simon Wunderlich <sw@simonwunderlich.de>,
	"Thiagarajan, Vasanthakumar" <vthiagar@qti.qualcomm.com>,
	Sebastian Gottschall <s.gottschall@dd-wrt.com>,
	michal.kazior@tieto.com,
	Mathias Kretschmer <mathias.kretschmer@fit.fraunhofer.de>,
	linux-wireless@vger.kernel.org,
	Benjamin Berg <benjamin@sipsolutions.net>
Subject: [PATCH] ath10k: Fix spinlock use in coverage class hack
Date: Wed, 14 Sep 2016 18:32:31 +0200	[thread overview]
Message-ID: <20160914163231.20863-1-benjamin@sipsolutions.net> (raw)
In-Reply-To: <8760q0j8st.fsf@kamboji.qca.qualcomm.com>

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 <benjamin@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

WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Berg <benjamin@sipsolutions.net>
To: "Valo, Kalle" <kvalo@qca.qualcomm.com>
Cc: Simon Wunderlich <sw@simonwunderlich.de>,
	"Thiagarajan, Vasanthakumar" <vthiagar@qti.qualcomm.com>,
	Benjamin Berg <benjamin@sipsolutions.net>,
	linux-wireless@vger.kernel.org,
	Sebastian Gottschall <s.gottschall@dd-wrt.com>,
	"ath10k @ lists . infradead . org" <ath10k@lists.infradead.org>,
	michal.kazior@tieto.com,
	Mathias Kretschmer <mathias.kretschmer@fit.fraunhofer.de>
Subject: [PATCH] ath10k: Fix spinlock use in coverage class hack
Date: Wed, 14 Sep 2016 18:32:31 +0200	[thread overview]
Message-ID: <20160914163231.20863-1-benjamin@sipsolutions.net> (raw)
In-Reply-To: <8760q0j8st.fsf@kamboji.qca.qualcomm.com>

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 <benjamin@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


_______________________________________________
ath10k mailing list
ath10k@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/ath10k

  reply	other threads:[~2016-09-14 16:32 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-29 14:45 [PATCHv3 0/5] ath10k: Allow setting coverage class and rx cleanups Benjamin Berg
2016-08-29 14:45 ` [PATCHv3 1/5] ath10k: Move ath10k_hw_params definition to hw.h Benjamin Berg
2016-09-13 12:32   ` [PATCHv3,1/5] " Kalle Valo
2016-08-29 14:45 ` [PATCHv3 2/5] ath10k: Add provision for Rx descriptor abstraction Benjamin Berg
2016-08-29 14:45 ` [PATCHv3 3/5] ath10k: Properly remove padding from the start of rx payload Benjamin Berg
2016-08-29 14:45 ` [PATCHv3 4/5] ath10k: Remove 4-addr padding related hw_param configuration Benjamin Berg
2016-08-29 14:45 ` [PATCHv3 5/5] ath10k: Allow setting coverage class Benjamin Berg
2016-09-13 12:14   ` Valo, Kalle
2016-09-14 16:32     ` Benjamin Berg [this message]
2016-09-14 16:32       ` [PATCH] ath10k: Fix spinlock use in coverage class hack Benjamin Berg
2016-09-30 12:58       ` Valo, Kalle
2016-09-30 12:58         ` Valo, Kalle
2016-10-04 15:04   ` [PATCHv3,5/5] ath10k: Allow setting coverage class Kalle Valo
2016-09-09 14:59 ` [PATCHv3 0/5] ath10k: Allow setting coverage class and rx cleanups Valo, Kalle
2016-09-09 14:59   ` Valo, Kalle
2016-09-12 14:11   ` [PATCH] ath10k: Add missing CONFIG_ATH10K_DEBUGFS check Benjamin Berg
2016-09-12 14:11     ` Benjamin Berg
2016-09-14 12:29     ` Valo, Kalle
2016-09-14 12:29       ` Valo, Kalle

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20160914163231.20863-1-benjamin@sipsolutions.net \
    --to=benjamin@sipsolutions.net \
    --cc=ath10k@lists.infradead.org \
    --cc=kvalo@qca.qualcomm.com \
    --cc=linux-wireless@vger.kernel.org \
    --cc=mathias.kretschmer@fit.fraunhofer.de \
    --cc=michal.kazior@tieto.com \
    --cc=s.gottschall@dd-wrt.com \
    --cc=sw@simonwunderlich.de \
    --cc=vthiagar@qti.qualcomm.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.