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[24.9.64.241]) by smtp.gmail.com with ESMTPSA id y25sm5594060ioa.5.2021.02.26.09.52.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 26 Feb 2021 09:52:17 -0800 (PST) From: Shuah Khan To: peterz@infradead.org, mingo@redhat.com, will@kernel.org, kvalo@codeaurora.org, davem@davemloft.net, kuba@kernel.org Cc: Shuah Khan , ath10k@lists.infradead.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 0/3] Add lockdep_assert_not_held() Date: Fri, 26 Feb 2021 10:52:12 -0700 Message-Id: X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Some kernel functions must not be called holding a specific lock. Doing so could lead to locking problems. Currently these routines call lock_is_held() to check for lock hold followed by WARN_ON. Adding a common lockdep interface will help reduce the duplication of this logic in the rest of the kernel. Add lockdep_assert_not_held() to be used in these functions to detect incorrect calls while holding a lock. lockdep_assert_not_held() provides the opposite functionality of lockdep_assert_held() which is used to assert calls that require holding a specific lock. The need for lockdep_assert_not_held() came up in a discussion on ath10k patch. ath10k_drain_tx() and i915_vma_pin_ww() are examples of functions that can use lockdep_assert_not_held(). Link: https://lore.kernel.org/lkml/37a29c383bff2fb1605241ee6c7c9be3784fb3c6.1613171185.git.skhan@linuxfoundation.org/ Link: https://lore.kernel.org/linux-wireless/871rdmu9z9.fsf@codeaurora.org/ This patch series adds lockdep_assert_not_held() and uses it in the second patch in ath10k_drain_tx() function. Patch 1 incorporates suggestions from Peter Zijlstra on v1 series to avoid misfires when lockdep_off() is employed. Patch 2 Johannes Berg's suggestions as it make it easier to read and maintain the lock states. These are defines and a enum to avoid changes to lock_is_held_type() and lockdep_is_held() return types. Patch 2 is a separate patch because it adds defines to lockdep.h and kernel/locking/lockdep.c now includes lockdep.h - decided make this a separate patch just in case issues related to header dependencies pop up. I can combine Patches 1&2 if that is preferred. Patch 3 uses the new interface in ath10k_drain_tx() function. Added Kalle Valo's Ack from v1 for this change. Tested on the mainline from yesterday. Shuah Khan (3): lockdep: add lockdep_assert_not_held() lockdep: add lockdep lock state defines ath10k: detect conf_mutex held ath10k_drain_tx() calls drivers/net/wireless/ath/ath10k/mac.c | 2 ++ include/linux/lockdep.h | 18 +++++++++++++++--- kernel/locking/lockdep.c | 6 +++++- 3 files changed, 22 insertions(+), 4 deletions(-)