From: Michael S. Tsirkin Date: Sun, 26 May 2013 14:32:23 +0000 (+0300) Subject: mm, sched: Allow uaccess in atomic with pagefault_disable() X-Git-Tag: omap-for-v3.11/fixes-for-merge-window~60^2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=662bbcb2747c2422cf98d3d97619509379eee466;p=pandora-kernel.git mm, sched: Allow uaccess in atomic with pagefault_disable() This changes might_fault() so that it does not trigger a false positive diagnostic for e.g. the following sequence: spin_lock_irqsave() pagefault_disable() copy_to_user() pagefault_enable() spin_unlock_irqrestore() In particular vhost wants to do this, to call socket ops from under a lock. There are 3 cases to consider: - CONFIG_PROVE_LOCKING - might_fault is non-inline so it's easy to move the in_atomic test to fix up the false positive warning. - CONFIG_DEBUG_ATOMIC_SLEEP - might_fault is currently inline, but we are calling a non-inline __might_sleep anyway, so let's use the non-line version of might_fault that does the right thing. - !CONFIG_DEBUG_ATOMIC_SLEEP && !CONFIG_PROVE_LOCKING __might_sleep is a nop so might_fault is a nop. Make this explicit. Signed-off-by: Michael S. Tsirkin Signed-off-by: Peter Zijlstra Cc: Linus Torvalds Cc: Andrew Morton Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1369577426-26721-11-git-send-email-mst@redhat.com Signed-off-by: Ingo Molnar --- Reading git-diff-tree failed