From patchwork Mon Jan 21 17:42:16 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Davidlohr Bueso X-Patchwork-Id: 10774275 X-Patchwork-Delegate: jgg@ziepe.ca Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7F2646C2 for ; Mon, 21 Jan 2019 17:43:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6942A29F0F for ; Mon, 21 Jan 2019 17:43:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5D79F2A6E0; Mon, 21 Jan 2019 17:43:30 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E980629F0F for ; Mon, 21 Jan 2019 17:43:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728239AbfAURnB (ORCPT ); Mon, 21 Jan 2019 12:43:01 -0500 Received: from smtp2.provo.novell.com ([137.65.250.81]:42442 "EHLO smtp2.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726003AbfAURm4 (ORCPT ); Mon, 21 Jan 2019 12:42:56 -0500 Received: from localhost.localdomain (prv-ext-foundry1int.gns.novell.com [137.65.251.240]) by smtp2.provo.novell.com with ESMTP (TLS encrypted); Mon, 21 Jan 2019 10:42:48 -0700 From: Davidlohr Bueso To: akpm@linux-foundation.org Cc: dledford@redhat.com, jgg@mellanox.com, jack@suse.de, ira.weiny@intel.com, linux-rdma@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, dave@stgolabs.net, sudeep.dutt@intel.com, ashutosh.dixit@intel.com, Davidlohr Bueso Subject: [PATCH 2/6] mic/scif: do not use mmap_sem Date: Mon, 21 Jan 2019 09:42:16 -0800 Message-Id: <20190121174220.10583-3-dave@stgolabs.net> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20190121174220.10583-1-dave@stgolabs.net> References: <20190121174220.10583-1-dave@stgolabs.net> Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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. Cc: sudeep.dutt@intel.com Cc: ashutosh.dixit@intel.com Reviewed-by: Ira Weiny Signed-off-by: Davidlohr Bueso --- drivers/misc/mic/scif/scif_rma.c | 36 +++++++++++------------------------- 1 file changed, 11 insertions(+), 25 deletions(-) diff --git a/drivers/misc/mic/scif/scif_rma.c b/drivers/misc/mic/scif/scif_rma.c index 2448368f181e..263b8ad507ea 100644 --- a/drivers/misc/mic/scif/scif_rma.c +++ b/drivers/misc/mic/scif/scif_rma.c @@ -272,21 +272,12 @@ static inline void __scif_release_mm(struct mm_struct *mm) static inline int __scif_dec_pinned_vm_lock(struct mm_struct *mm, - int nr_pages, bool try_lock) + int nr_pages) { if (!mm || !nr_pages || !scif_ulimit_check) return 0; - if (try_lock) { - if (!down_write_trylock(&mm->mmap_sem)) { - dev_err(scif_info.mdev.this_device, - "%s %d err\n", __func__, __LINE__); - return -1; - } - } else { - down_write(&mm->mmap_sem); - } + atomic64_sub(nr_pages, &mm->pinned_vm); - up_write(&mm->mmap_sem); return 0; } @@ -298,16 +289,16 @@ static inline int __scif_check_inc_pinned_vm(struct mm_struct *mm, if (!mm || !nr_pages || !scif_ulimit_check) return 0; - locked = nr_pages; - locked += atomic64_read(&mm->pinned_vm); lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; + locked = atomic64_add_return(nr_pages, &mm->pinned_vm); + if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) { + atomic64_sub(nr_pages, &mm->pinned_vm); dev_err(scif_info.mdev.this_device, "locked(%lu) > lock_limit(%lu)\n", locked, lock_limit); return -ENOMEM; } - atomic64_set(&mm->pinned_vm, locked); return 0; } @@ -326,7 +317,7 @@ int scif_destroy_window(struct scif_endpt *ep, struct scif_window *window) might_sleep(); if (!window->temp && window->mm) { - __scif_dec_pinned_vm_lock(window->mm, window->nr_pages, 0); + __scif_dec_pinned_vm_lock(window->mm, window->nr_pages); __scif_release_mm(window->mm); window->mm = NULL; } @@ -737,7 +728,7 @@ int scif_unregister_window(struct scif_window *window) ep->rma_info.dma_chan); } else { if (!__scif_dec_pinned_vm_lock(window->mm, - window->nr_pages, 1)) { + window->nr_pages)) { __scif_release_mm(window->mm); window->mm = NULL; } @@ -1385,28 +1376,23 @@ int __scif_pin_pages(void *addr, size_t len, int *out_prot, prot |= SCIF_PROT_WRITE; retry: mm = current->mm; - down_write(&mm->mmap_sem); if (ulimit) { err = __scif_check_inc_pinned_vm(mm, nr_pages); if (err) { - up_write(&mm->mmap_sem); pinned_pages->nr_pages = 0; goto error_unmap; } } - pinned_pages->nr_pages = get_user_pages( + pinned_pages->nr_pages = get_user_pages_fast( (u64)addr, nr_pages, (prot & SCIF_PROT_WRITE) ? FOLL_WRITE : 0, - pinned_pages->pages, - NULL); - up_write(&mm->mmap_sem); + pinned_pages->pages); if (nr_pages != pinned_pages->nr_pages) { if (try_upgrade) { if (ulimit) - __scif_dec_pinned_vm_lock(mm, - nr_pages, 0); + __scif_dec_pinned_vm_lock(mm, nr_pages); /* Roll back any pinned pages */ for (i = 0; i < pinned_pages->nr_pages; i++) { if (pinned_pages->pages[i]) @@ -1433,7 +1419,7 @@ int __scif_pin_pages(void *addr, size_t len, int *out_prot, return err; dec_pinned: if (ulimit) - __scif_dec_pinned_vm_lock(mm, nr_pages, 0); + __scif_dec_pinned_vm_lock(mm, nr_pages); /* Something went wrong! Rollback */ error_unmap: pinned_pages->nr_pages = nr_pages;