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Fix comment about what we do when there are no listeners.

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This commit is contained in:
Warner Losh 2003-01-19 00:34:17 +00:00
parent 78b1878a16
commit b47d073500
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=109505
1 changed files with 3 additions and 13 deletions
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16
sys/kern/subr_bus.c
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@ -381,19 +381,9 @@ devpoll(dev_t dev, int events, d_thread_t *td)
* Common routine that tries to make sending messages as easy as possible.
* We allocate memory for the data, copy strings into that, but do not
* free it unless there's an error. The dequeue part of the driver should
* free the data. We do not send any data if there is no listeners on the
* /dev/devctl device. We assume that on startup, any program that wishes
* to do things based on devices that have attached before it starts will
* query the tree to find out its current state. This decision may
* be revisited if there are difficulties determining if one should do an
* action or not (eg, are all actions that the listening program idempotent
* or not). This may also open up races as well (say if the listener
* dies just before a device goes away, and is run again just after, no
* detach action would happen). The flip side would be that we'd need to
* limit the size of the queue because otherwise if no listener is running
* then we'd have unbounded growth. Most systems have less than 100 (maybe
* even less than 50) devices, so maybe a limit of 200 or 300 wouldn't be
* too horrible. XXX
* free the data. We don't send data when the device is disabled. We do
* send data, even when we have no listeners, because we wish to avoid
* races relating to startup and restart of listening applications.
*/
static void
devaddq(const char *type, const char *what, device_t dev)