Messages in this thread | | | Date | Thu, 15 May 2008 10:44:57 +0200 (CEST) | From | Jan Engelhardt <> | Subject | Re: [announce] "kill the Big Kernel Lock (BKL)" tree |
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On Wednesday 2008-05-14 23:45, Jonathan Corbet wrote: >Sez Ingo: >1: We could add an unlocked_open() to the file_operations structure; > drivers could be converted over as they are verified not to need the > BKL on open. Disadvantages are that it grows this structure for a > relatively rare case - most open() calls already don't need the BKL. > But it's a relatively easy path without flag days.
1b: add a .locked_open and move all BKL-requiring code to use that. When time comes and BKL is gone, .locked_open can be removed again, and no rename was ever done for BKL-free code.
>2: Create a char_dev_ops structure for char devs and use it instead of > file_operations. I vaguely remember seeing Al mutter about that a > while back. Quite a while back. This mirrors what was done with > block devices, and makes some sense - there's a lot of stuff in > struct file_operations which is not really applicable to char devs. > Then struct char_dev_ops could have open() and locked_open(), with > the latter destined for removal sometime around 2015 or so.
Iff you create a new char_dev_ops, don't clutter it with the old stuff. BKL-using code could continue using file_operations, would not it?
>3: Provide a new form of cdev_add() which lets the driver indicate > that the BKL is not needed on open (or anything else?). At a
This is the BSD/Solaris tactic, heh :)
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