| Subject | Re: [PATCH v4 25/32] tty: Add read-recursive, writer-prioritized rw semaphore | From | Peter Hurley <> | Date | Fri, 08 Mar 2013 12:12:42 -0500 |
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On Wed, 2013-02-20 at 15:03 -0500, Peter Hurley wrote: > The semantics of a rw semaphore are almost ideally suited > for tty line discipline lifetime management; multiple active > threads obtain "references" (read locks) while performing i/o > to prevent the loss or change of the current line discipline > (write lock). > > Unfortunately, the existing rw_semaphore is ill-suited in other > ways; > 1) obtaining a "reference" can be recursive, ie., a reference holder > may attempt to obtain another "reference". Recursive read locks > are not supported by rwsem.
Hi Greg,
I just finished auditing all the recursive usage of the tty/ldisc layer and I can make this lock non-recursive.
Please hold off applying this and I'll send you a v5 series in a couple of days, ok?
Regards, Peter Hurley
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