From: Ahmad Fatoum <a.fatoum@pengutronix.de> To: barebox@lists.infradead.org Cc: Ahmad Fatoum <a.fatoum@pengutronix.de> Subject: [PATCH v2 2/4] slice: reschedule bthreads doing File I/O in command context Date: Fri, 30 Apr 2021 15:40:59 +0200 [thread overview] Message-ID: <20210430134101.20580-3-a.fatoum@pengutronix.de> (raw) In-Reply-To: <20210430134101.20580-1-a.fatoum@pengutronix.de> Currently, without locks, it's unsafe to do file I/O outside of the main thread, be it in pollers or secondary bthreads. Pollers side step this issue by deferring file I/O to workqueues that run in command context: the time when the shell is waiting for input. For bthreads, we can do something similar without involving workqueues: We just suspend threads until they are scheduled in command context. This is not a full solution: Not everything that should assert_command_context() does so, so you still can't do absolutely everything in a secondary bthread. To get there, we will need to distribute locks across the code base, but that's a patchset for another time. Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de> --- include/slice.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/include/slice.h b/include/slice.h index cf684300a809..abe819163d32 100644 --- a/include/slice.h +++ b/include/slice.h @@ -40,8 +40,10 @@ extern int poller_active; #define assert_command_context() do { \ WARN_ONCE(IS_ENABLED(CONFIG_POLLER) && poller_active, \ "%s called in poller\n", __func__); \ - WARN_ONCE(IS_ENABLED(CONFIG_BTHREAD) && !bthread_is_main(current), \ - "%s called in secondary bthread\n", __func__); \ + if (IS_ENABLED(CONFIG_BTHREAD) && !bthread_is_main(current)) { \ + while (slice_acquired(&command_slice)) \ + bthread_reschedule(); \ + } \ } while (0) #endif -- 2.29.2 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox
next prev parent reply other threads:[~2021-04-30 13:42 UTC|newest] Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-04-30 13:40 [PATCH v2 0/4] usbgadget: add support for USB mass storage gadget Ahmad Fatoum 2021-04-30 13:40 ` [PATCH v2 1/4] bthread: implement basic Linux-like completion API Ahmad Fatoum 2021-04-30 13:40 ` Ahmad Fatoum [this message] 2021-04-30 13:41 ` [PATCH v2 3/4] usbgadget: refactor usbgadget_register to accept array Ahmad Fatoum 2021-04-30 13:41 ` [PATCH v2 4/4] usbgadget: add support for USB mass storage gadget Ahmad Fatoum
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