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author | Hugh Dickins <hugh@veritas.com> | 2005-10-29 18:16:33 -0700 |
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committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-10-29 21:40:41 -0700 |
commit | deceb6cd17e6dfafe4c4f81b1b4153bc41b2cb70 (patch) | |
tree | 2a722f50e8edef8609a49f65bfcb222e499c44cc /kernel/futex.c | |
parent | c34d1b4d165c67b966bca4aba026443d7ff161eb (diff) | |
download | kernel_samsung_smdk4412-deceb6cd17e6dfafe4c4f81b1b4153bc41b2cb70.zip kernel_samsung_smdk4412-deceb6cd17e6dfafe4c4f81b1b4153bc41b2cb70.tar.gz kernel_samsung_smdk4412-deceb6cd17e6dfafe4c4f81b1b4153bc41b2cb70.tar.bz2 |
[PATCH] mm: follow_page with inner ptlock
Final step in pushing down common core's page_table_lock. follow_page no
longer wants caller to hold page_table_lock, uses pte_offset_map_lock itself;
and so no page_table_lock is taken in get_user_pages itself.
But get_user_pages (and get_futex_key) do then need follow_page to pin the
page for them: take Daniel's suggestion of bitflags to follow_page.
Need one for WRITE, another for TOUCH (it was the accessed flag before:
vanished along with check_user_page_readable, but surely get_numa_maps is
wrong to mark every page it finds as accessed), another for GET.
And another, ANON to dispose of untouched_anonymous_page: it seems silly for
that to descend a second time, let follow_page observe if there was no page
table and return ZERO_PAGE if so. Fix minor bug in that: check VM_LOCKED -
make_pages_present ought to make readonly anonymous present.
Give get_numa_maps a cond_resched while we're there.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/futex.c')
-rw-r--r-- | kernel/futex.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index ca05fe6..3b4d5ad 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -205,15 +205,13 @@ static int get_futex_key(unsigned long uaddr, union futex_key *key) /* * Do a quick atomic lookup first - this is the fastpath. */ - spin_lock(¤t->mm->page_table_lock); - page = follow_page(mm, uaddr, 0); + page = follow_page(mm, uaddr, FOLL_TOUCH|FOLL_GET); if (likely(page != NULL)) { key->shared.pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); - spin_unlock(¤t->mm->page_table_lock); + put_page(page); return 0; } - spin_unlock(¤t->mm->page_table_lock); /* * Do it the general way. |