Function 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_unlocked() and leave mmap_sem locking for mm.
CC: Mike Marciniszyn <[email protected]> CC: Roland Dreier <[email protected]> CC: [email protected] Signed-off-by: Jan Kara <[email protected]> --- drivers/infiniband/hw/ipath/ipath_user_sdma.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/drivers/infiniband/hw/ipath/ipath_user_sdma.c b/drivers/infiniband/hw/ipath/ipath_user_sdma.c index f5cb13b21445..462c9b136e85 100644 --- a/drivers/infiniband/hw/ipath/ipath_user_sdma.c +++ b/drivers/infiniband/hw/ipath/ipath_user_sdma.c @@ -280,8 +280,8 @@ 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_unlocked(current, current->mm, addr, + npages, 0, 1, pages); if (ret != npages) { int i; @@ -811,10 +811,7 @@ 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 { -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
