{"id":10903,"url":"https://patchwork.libcamera.org/api/patches/10903/?format=json","web_url":"https://patchwork.libcamera.org/patch/10903/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/projects/1/?format=json","name":"libcamera","link_name":"libcamera","list_id":"libcamera_core","list_email":"libcamera-devel@lists.libcamera.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20210119233315.3305649-1-niklas.soderlund@ragnatech.se>","date":"2021-01-19T23:33:15","name":"[libcamera-devel,v2] cam: event_loop: Stop processing calls when event loop is exiting","commit_ref":null,"pull_url":null,"state":"superseded","archived":false,"hash":"2c61d7fcef4fcb79ced1c8f440cfb29ffe4f661f","submitter":{"id":5,"url":"https://patchwork.libcamera.org/api/people/5/?format=json","name":"Niklas Söderlund","email":"niklas.soderlund@ragnatech.se"},"delegate":{"id":16,"url":"https://patchwork.libcamera.org/api/users/16/?format=json","username":"neg","first_name":"Niklas","last_name":"Söderlund","email":"niklas.soderlund@ragnatech.se"},"mbox":"https://patchwork.libcamera.org/patch/10903/mbox/","series":[{"id":1586,"url":"https://patchwork.libcamera.org/api/series/1586/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=1586","date":"2021-01-19T23:33:15","name":"[libcamera-devel,v2] cam: event_loop: Stop processing calls when event loop is exiting","version":2,"mbox":"https://patchwork.libcamera.org/series/1586/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/10903/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/10903/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id ED3C9C0F1C\n\tfor ;\n\tTue, 19 Jan 2021 23:33:25 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id CAB4A68170;\n\tWed, 20 Jan 2021 00:33:25 +0100 (CET)","from bin-mail-out-05.binero.net (bin-mail-out-05.binero.net\n\t[195.74.38.228])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 2A1AB6010B\n\tfor ;\n\tWed, 20 Jan 2021 00:33:24 +0100 (CET)","from bismarck.berto.se (p4fca2458.dip0.t-ipconnect.de\n\t[79.202.36.88])\n\tby bin-vsp-out-02.atm.binero.net (Halon) with ESMTPA\n\tid b5de9dfd-5aae-11eb-a076-005056917f90;\n\tWed, 20 Jan 2021 00:33:22 +0100 (CET)"],"X-Halon-ID":"b5de9dfd-5aae-11eb-a076-005056917f90","Authorized-sender":"niklas.soderlund@fsdn.se","From":"=?utf-8?q?Niklas_S=C3=B6derlund?= ","To":"libcamera-devel@lists.libcamera.org","Date":"Wed, 20 Jan 2021 00:33:15 +0100","Message-Id":"<20210119233315.3305649-1-niklas.soderlund@ragnatech.se>","X-Mailer":"git-send-email 2.30.0","MIME-Version":"1.0","Subject":"[libcamera-devel] [PATCH v2] cam: event_loop: Stop processing calls\n\twhen event loop is exiting","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Content-Type":"text/plain; charset=\"utf-8\"","Content-Transfer-Encoding":"base64","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "},"content":"Terminating the event loop with EventLoop::exit() does not grantee that\nit will terminate. If the event loops 'call later' queue can be kept\nnon-empty by continuously queuing new calls using EventLoop::callLater()\neither from a different thread or from callbacks in the loop itself\nEventLoop::dispatchCalls() will never complete and the loop will run\nforever.\n\nSolve this by evaluating the exit condition between each callback and\nonly enter the idle loop if there are no callbacks to process.\n\nReported-by: Sebastian Fricke \nFixes: f49e93338b6309a6 (\"cam: event_loop: Add deferred calls support\")\nSigned-off-by: Niklas Söderlund \n---\n* Changes since v1\n- Was [PATCH 0/2] cam: Fix races in event loop and long request\n processing times\n- Rework dispatchCalls() instead of callLater() for a simpler fix.\n---\n src/cam/event_loop.cpp | 22 +++++++++++++---------\n src/cam/event_loop.h | 2 +-\n 2 files changed, 14 insertions(+), 10 deletions(-)","diff":"diff --git a/src/cam/event_loop.cpp b/src/cam/event_loop.cpp\nindex 94c5d1d362455f33..18786b4500be9b6f 100644\n--- a/src/cam/event_loop.cpp\n+++ b/src/cam/event_loop.cpp\n@@ -41,7 +41,9 @@ int EventLoop::exec()\n \texit_.store(false, std::memory_order_release);\n \n \twhile (!exit_.load(std::memory_order_acquire)) {\n-\t\tdispatchCalls();\n+\t\tif (dispatchCall())\n+\t\t\tcontinue;\n+\n \t\tevent_base_loop(event_, EVLOOP_NO_EXIT_ON_EMPTY);\n \t}\n \n@@ -70,17 +72,19 @@ void EventLoop::callLater(const std::function &func)\n \tinterrupt();\n }\n \n-void EventLoop::dispatchCalls()\n+bool EventLoop::dispatchCall()\n {\n \tstd::unique_lock locker(lock_);\n \n-\tfor (auto iter = calls_.begin(); iter != calls_.end(); ) {\n-\t\tstd::function call = std::move(*iter);\n+\tif (calls_.empty())\n+\t\treturn false;\n \n-\t\titer = calls_.erase(iter);\n+\tauto iter = calls_.begin();\n+\tstd::function call = std::move(*iter);\n+\tcalls_.erase(iter);\n \n-\t\tlocker.unlock();\n-\t\tcall();\n-\t\tlocker.lock();\n-\t}\n+\tlocker.unlock();\n+\tcall();\n+\n+\treturn true;\n }\ndiff --git a/src/cam/event_loop.h b/src/cam/event_loop.h\nindex 408073c50594d09d..b84e1c9e432086e3 100644\n--- a/src/cam/event_loop.h\n+++ b/src/cam/event_loop.h\n@@ -38,7 +38,7 @@ private:\n \tstd::mutex lock_;\n \n \tvoid interrupt();\n-\tvoid dispatchCalls();\n+\tbool dispatchCall();\n };\n \n #endif /* __CAM_EVENT_LOOP_H__ */\n","prefixes":["libcamera-devel","v2"]}