[lkml]   [2001]   [Dec]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH] remove BKL from drivers' release functions
    This is why we have a development tree. Its moving things in the
right direction which is important. I suspect many drivers will
want to use semaphores rather than atomic counts however, to ensure
that an open doesn't complete while a previous release is still
shutting down hardware

Yes, the only successful application for atomic counts that I've seen
(in this context) is for exclusive open code that looks like

if (count++) {
return -EBUSY;

in the open routine and


in the release. If you want to do anything else as a result of that
count, you'll need additional locking because it could have changed a
nanosecond after it was (safely) incremented or decremented. You can't
count on it remaining that value after you check it.

release()s that want to shutdown the device, free memory, or take other
actions will want to employ either a spinlock (plain or r/w as
appropriate) or a sleeping semaphore to insure things remain stable
until those actions are complete.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-03-22 13:13    [W:0.108 / U:0.048 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site