Messages in this thread | | | Date | Tue, 21 Oct 2008 13:42:42 -0700 | From | "Dan Williams" <> | Subject | Re: Best method for sending messages to user space? |
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On Tue, Oct 21, 2008 at 1:23 PM, Timur Tabi <timur@freescale.com> wrote: > Dan Williams wrote: > >> fd = open("/sys/block/md0/md/array_state"); >> do { >> read(buf, fd, len); >> act_on_message(buf); >> select(...); /* wait for next sysfs_notify event */ >> lseek(fd, 0, SEEK_SET); /* seek back so we can read the new state */ >> } while (1); > > I meant from the kernel side. I added a call to sysfs_notify(), and I didn't > see any sysfs entries being created, so I presume I need to set up sysfs before > I call sysfs_notify(), but I can't figure out what that setup is. >
sysfs_notify() will not create any files it only operates on pre-existing attributes created via kobject_{init_and_}add(). See: http://lxr.linux.no/linux+v2.6.27/drivers/md/md.c#L3473 http://lxr.linux.no/linux+v2.6.27/drivers/md/md.c#L3761
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