diff options
| author | Jan Kara <jack@suse.cz> | 2013-10-04 15:29:06 +0200 |
|---|---|---|
| committer | Roland Dreier <roland@purestorage.com> | 2013-11-08 23:43:11 +0100 |
| commit | 4adcf7fb6783e354aab38824d803fa8c4f8e8a27 (patch) | |
| tree | 6aaa86095a45cf4c845090f025c0a1543d5cbbcb /drivers/infiniband | |
| parent | Linux 3.12-rc7 (diff) | |
| download | linux-4adcf7fb6783e354aab38824d803fa8c4f8e8a27.tar.xz linux-4adcf7fb6783e354aab38824d803fa8c4f8e8a27.zip | |
IB/ipath: Convert ipath_user_sdma_pin_pages() to use get_user_pages_fast()
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.
Cc: <stable@vger.kernel.org>
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>
Diffstat (limited to 'drivers/infiniband')
| -rw-r--r-- | drivers/infiniband/hw/ipath/ipath_user_sdma.c | 7 |
1 files changed, 1 insertions, 6 deletions
diff --git a/drivers/infiniband/hw/ipath/ipath_user_sdma.c b/drivers/infiniband/hw/ipath/ipath_user_sdma.c index f5cb13b21445..cc04b7ba3488 100644 --- a/drivers/infiniband/hw/ipath/ipath_user_sdma.c +++ b/drivers/infiniband/hw/ipath/ipath_user_sdma.c @@ -280,9 +280,7 @@ static int ipath_user_sdma_pin_pages(const struct ipath_devdata *dd, int j; int ret; - ret = get_user_pages(current, current->mm, addr, - npages, 0, 1, pages, NULL); - + ret = get_user_pages_fast(addr, npages, 0, pages); if (ret != npages) { int i; @@ -811,10 +809,7 @@ int ipath_user_sdma_writev(struct ipath_devdata *dd, while (dim) { const int mxp = 8; - down_write(¤t->mm->mmap_sem); ret = ipath_user_sdma_queue_pkts(dd, pq, &list, iov, dim, mxp); - up_write(¤t->mm->mmap_sem); - if (ret <= 0) goto done_unlock; else { |