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| author | Jan Kara <jack@suse.cz> | 2013-10-04 09:29:06 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-12-04 10:56:16 -0800 |
| commit | eef5ed304aa7b49b8f58720855dd299163329db2 (patch) | |
| tree | a60a6eca4bf65b5eddbc1001a25350eb9c4754f0 /Makefile | |
| parent | 6aec95b47deb9e3dad4cb2e6db87f3b03544224d (diff) | |
| download | linux-3.10-eef5ed304aa7b49b8f58720855dd299163329db2.tar.gz linux-3.10-eef5ed304aa7b49b8f58720855dd299163329db2.tar.bz2 linux-3.10-eef5ed304aa7b49b8f58720855dd299163329db2.zip | |
IB/ipath: Convert ipath_user_sdma_pin_pages() to use get_user_pages_fast()
commit 4adcf7fb6783e354aab38824d803fa8c4f8e8a27 upstream.
ipath_user_sdma_queue_pkts() gets called with mmap_sem held for
writing. Except for get_user_pages() deep down in
ipath_user_sdma_pin_pages() we don't seem to need mmap_sem at all.
Even more interestingly the function ipath_user_sdma_queue_pkts() (and
also ipath_user_sdma_coalesce() called somewhat later) call
copy_from_user() which can hit a page fault and we deadlock on trying
to get mmap_sem when handling that fault. So just make
ipath_user_sdma_pin_pages() use get_user_pages_fast() and leave
mmap_sem locking for mm.
This deadlock has actually been observed in the wild when the node
is under memory pressure.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
[ Merged in fix for call to get_user_pages_fast from Tetsuo Handa
<penguin-kernel@I-love.SAKURA.ne.jp>. - Roland ]
Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Makefile')
0 files changed, 0 insertions, 0 deletions