Messages in this thread | | | From | Dmitry Vyukov <> | Date | Fri, 28 Aug 2015 19:34:33 +0200 | Subject | Re: Potential data race in psmouse_interrupt |
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Hello,
I am looking at this code in __ps2_command again:
/* * The reset command takes a long time to execute. */ timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500);
timeout = wait_event_timeout(ps2dev->wait, !(READ_ONCE(ps2dev->flags) & PS2_FLAG_CMD1), timeout);
if (smp_load_acquire(&ps2dev->cmdcnt) && !(smp_load_acquire(&ps2dev->flags) & PS2_FLAG_CMD1)) { timeout = ps2_adjust_timeout(ps2dev, command, timeout); wait_event_timeout(ps2dev->wait, !(smp_load_acquire(&ps2dev->flags) & PS2_FLAG_CMD), timeout); }
if (param) for (i = 0; i < receive; i++) param[i] = ps2dev->cmdbuf[(receive - 1) - i];
Here are two moments I don't understand: 1. The last parameter of ps2_adjust_timeout is timeout in jiffies (it is compared against 100ms). However, timeout is assigned to result of wait_event_timeout, which returns 0 or 1. This does not make sense to me. What am I missing? 2. This code pays great attention to timeouts, but in the end I don't see how it handles timeouts. That is, if a timeout is happened, we still copyout (garbage) from cmdbuf. What am I missing here?
Thank you
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