[Bug 1699 (linux mm)] Changed - change mmap_sem to R/W lock

[bugzilla-daemon@distro.conectiva.com.br]

http://distro.conectiva.com.br/bugzilla/show_bug.cgi?id=1699





------- Additional Comments From sct@redhat.com  2001-03-15 10:40 -------
We already have a per-mm page fault lock, the page_table_lock spinlock.  It's
pretty trivial to avoid page fault races with that existing lock.  The worst you
have to do is to make sure that you do a consistent read/modify/write of the pte
without dropping the lock, so you have to be prepared to return early from the
page fault and try again if you detect that a fault has already happened by the
time you get around to taking or retaking the lock yourself.

It's a 2.5 issue --- there are too many places for subtle things to go wrong ---
but it's not a major rearchitecture.
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