From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: [patch 099/127] rapidio: convert get_user_pages() --> pin_user_pages() Date: Thu, 04 Jun 2020 16:51:24 -0700 Message-ID: <20200604235124.yy4ZYudd-%akpm@linux-foundation.org> References: <20200604164523.e15f3177f4b69dcb4f2534a1@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.99]:49930 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725943AbgFDXv0 (ORCPT ); Thu, 4 Jun 2020 19:51:26 -0400 In-Reply-To: <20200604164523.e15f3177f4b69dcb4f2534a1@linux-foundation.org> Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: akpm@linux-foundation.org, alex.bou9@gmail.com, dan.carpenter@oracle.com, jhubbard@nvidia.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, mporter@kernel.crashing.org, sumit.semwal@linaro.org, torvalds@linux-foundation.org From: John Hubbard Subject: rapidio: convert get_user_pages() --> pin_user_pages() This code was using get_user_pages_fast(), in a "Case 2" scenario (DMA/RDMA), using the categorization from [1]. That means that it's time to convert the get_user_pages_fast() + put_page() calls to pin_user_pages_fast() + unpin_user_pages() calls. There is some helpful background in [2]: basically, this is a small part of fixing a long-standing disconnect between pinning pages, and file systems' use of those pages. [1] Documentation/core-api/pin_user_pages.rst [2] "Explicit pinning of user-space pages": https://lwn.net/Articles/807108/ Link: http://lkml.kernel.org/r/20200517235620.205225-3-jhubbard@nvidia.com Signed-off-by: John Hubbard Cc: Matt Porter Cc: Alexandre Bounine Cc: Sumit Semwal Cc: Dan Carpenter Signed-off-by: Andrew Morton --- drivers/rapidio/devices/rio_mport_cdev.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) --- a/drivers/rapidio/devices/rio_mport_cdev.c~rapidio-convert-get_user_pages-pin_user_pages +++ a/drivers/rapidio/devices/rio_mport_cdev.c @@ -572,14 +572,12 @@ static void dma_req_free(struct kref *re struct mport_dma_req *req = container_of(ref, struct mport_dma_req, refcount); struct mport_cdev_priv *priv = req->priv; - unsigned int i; dma_unmap_sg(req->dmach->device->dev, req->sgt.sgl, req->sgt.nents, req->dir); sg_free_table(&req->sgt); if (req->page_list) { - for (i = 0; i < req->nr_pages; i++) - put_page(req->page_list[i]); + unpin_user_pages(req->page_list, req->nr_pages); kfree(req->page_list); } @@ -815,7 +813,7 @@ rio_dma_transfer(struct file *filp, u32 struct mport_dma_req *req; struct mport_dev *md = priv->md; struct dma_chan *chan; - int i, ret; + int ret; int nents; if (xfer->length == 0) @@ -862,7 +860,7 @@ rio_dma_transfer(struct file *filp, u32 goto err_req; } - pinned = get_user_pages_fast( + pinned = pin_user_pages_fast( (unsigned long)xfer->loc_addr & PAGE_MASK, nr_pages, dir == DMA_FROM_DEVICE ? FOLL_WRITE : 0, @@ -870,7 +868,7 @@ rio_dma_transfer(struct file *filp, u32 if (pinned != nr_pages) { if (pinned < 0) { - rmcd_error("get_user_pages_unlocked err=%ld", + rmcd_error("pin_user_pages_fast err=%ld", pinned); nr_pages = 0; } else @@ -951,8 +949,7 @@ rio_dma_transfer(struct file *filp, u32 err_pg: if (!req->page_list) { - for (i = 0; i < nr_pages; i++) - put_page(page_list[i]); + unpin_user_pages(page_list, nr_pages); kfree(page_list); } err_req: _