From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [PATCH 3/6] drivers/IB,qib: do not use mmap_sem Date: Mon, 28 Jan 2019 16:31:40 -0700 Message-ID: <20190128233140.GA12530@ziepe.ca> References: <20190121174220.10583-1-dave@stgolabs.net> <20190121174220.10583-4-dave@stgolabs.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20190121174220.10583-4-dave@stgolabs.net> Sender: linux-kernel-owner@vger.kernel.org To: Davidlohr Bueso Cc: akpm@linux-foundation.org, dledford@redhat.com, jack@suse.de, ira.weiny@intel.com, linux-rdma@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, dennis.dalessandro@intel.com, mike.marciniszyn@intel.com, Davidlohr Bueso List-Id: linux-rdma@vger.kernel.org On Mon, Jan 21, 2019 at 09:42:17AM -0800, Davidlohr Bueso wrote: > The driver uses mmap_sem for both pinned_vm accounting and > get_user_pages(). By using gup_fast() and letting the mm handle > the lock if needed, we can no longer rely on the semaphore and > simplify the whole thing as the pinning is decoupled from the lock. > > This also fixes a bug that __qib_get_user_pages was not taking into > account the current value of pinned_vm. > > Cc: dennis.dalessandro@intel.com > Cc: mike.marciniszyn@intel.com > Reviewed-by: Ira Weiny > Signed-off-by: Davidlohr Bueso > --- > drivers/infiniband/hw/qib/qib_user_pages.c | 67 ++++++++++-------------------- > 1 file changed, 22 insertions(+), 45 deletions(-) I need you to respin this patch/series against the latest rdma tree: git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git branch for-next > diff --git a/drivers/infiniband/hw/qib/qib_user_pages.c b/drivers/infiniband/hw/qib/qib_user_pages.c > -static int __qib_get_user_pages(unsigned long start_page, size_t num_pages, > - struct page **p) > -{ > - unsigned long lock_limit; > - size_t got; > - int ret; > - > - lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; > - > - if (num_pages > lock_limit && !capable(CAP_IPC_LOCK)) { > - ret = -ENOMEM; > - goto bail; > - } > - > - for (got = 0; got < num_pages; got += ret) { > - ret = get_user_pages(start_page + got * PAGE_SIZE, > - num_pages - got, > - FOLL_WRITE | FOLL_FORCE, > - p + got, NULL); As this has been rightly changed to get_user_pages_longterm, and I think the right answer to solve the conflict is to discard some of this patch? Since Andrew is OK with this I can move this ahead once this is resolved, thanks. Jason