From mboxrd@z Thu Jan 1 00:00:00 1970 From: john.hubbard@gmail.com Subject: [PATCH v2 20/34] xen: convert put_page() to put_user_page*() Date: Sun, 4 Aug 2019 15:49:01 -0700 Message-ID: <20190804224915.28669-21-jhubbard@nvidia.com> References: <20190804224915.28669-1-jhubbard@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190804224915.28669-1-jhubbard@nvidia.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: driverdev-devel-bounces@linuxdriverproject.org Sender: "devel" To: Andrew Morton Cc: linux-fbdev@vger.kernel.org, Jan Kara , kvm@vger.kernel.org, Boris Ostrovsky , Dave Hansen , Dave Chinner , dri-devel@lists.freedesktop.org, linux-mm@kvack.org, sparclinux@vger.kernel.org, ceph-devel@vger.kernel.org, devel@driverdev.osuosl.org, rds-devel@oss.oracle.com, linux-rdma@vger.kernel.org, x86@kernel.org, amd-gfx@lists.freedesktop.org, Christoph Hellwig , Jason Gunthorpe , xen-devel@lists.xenproject.org, devel@lists.orangefs.org, linux-media@vger.kernel.org, John Hubbard , intel-gfx@lists.freedesktop.org, linux-block@vger.kernel.org, =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , linux-rpi-kernel@lists.infradead.org, Dan Williams , linux-arm-kernel@lists.infradead.org, Juergen List-Id: intel-gfx@lists.freedesktop.org From: John Hubbard For pages that were retained via get_user_pages*(), release those pages via the new put_user_page*() routines, instead of via put_page() or release_pages(). This is part a tree-wide conversion, as described in commit fc1d8e7cca2d ("mm: introduce put_user_page*(), placeholder versions"). This also handles pages[i] == NULL cases, thanks to an approach that is actually written by Juergen Gross. Signed-off-by: Juergen Gross Signed-off-by: John Hubbard Cc: Boris Ostrovsky Cc: xen-devel@lists.xenproject.org --- Hi Juergen, Say, this is *exactly* what you proposed in your gup.patch, so I've speculatively added your Signed-off-by above, but need your approval before that's final. Let me know please... thanks, John Hubbard drivers/xen/privcmd.c | 32 +++++++++++--------------------- 1 file changed, 11 insertions(+), 21 deletions(-) diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c index c6070e70dd73..c7d0763ca8c2 100644 --- a/drivers/xen/privcmd.c +++ b/drivers/xen/privcmd.c @@ -582,10 +582,11 @@ static long privcmd_ioctl_mmap_batch( static int lock_pages( struct privcmd_dm_op_buf kbufs[], unsigned int num, - struct page *pages[], unsigned int nr_pages) + struct page *pages[], unsigned int *nr_pages) { - unsigned int i; + unsigned int i, free = *nr_pages; + *nr_pages = 0; for (i = 0; i < num; i++) { unsigned int requested; int pinned; @@ -593,35 +594,22 @@ static int lock_pages( requested = DIV_ROUND_UP( offset_in_page(kbufs[i].uptr) + kbufs[i].size, PAGE_SIZE); - if (requested > nr_pages) + if (requested > free) return -ENOSPC; pinned = get_user_pages_fast( (unsigned long) kbufs[i].uptr, - requested, FOLL_WRITE, pages); + requested, FOLL_WRITE, pages + *nr_pages); if (pinned < 0) return pinned; - nr_pages -= pinned; - pages += pinned; + free -= pinned; + *nr_pages += pinned; } return 0; } -static void unlock_pages(struct page *pages[], unsigned int nr_pages) -{ - unsigned int i; - - if (!pages) - return; - - for (i = 0; i < nr_pages; i++) { - if (pages[i]) - put_page(pages[i]); - } -} - static long privcmd_ioctl_dm_op(struct file *file, void __user *udata) { struct privcmd_data *data = file->private_data; @@ -681,11 +669,12 @@ static long privcmd_ioctl_dm_op(struct file *file, void __user *udata) xbufs = kcalloc(kdata.num, sizeof(*xbufs), GFP_KERNEL); if (!xbufs) { + nr_pages = 0; rc = -ENOMEM; goto out; } - rc = lock_pages(kbufs, kdata.num, pages, nr_pages); + rc = lock_pages(kbufs, kdata.num, pages, &nr_pages); if (rc) goto out; @@ -699,7 +688,8 @@ static long privcmd_ioctl_dm_op(struct file *file, void __user *udata) xen_preemptible_hcall_end(); out: - unlock_pages(pages, nr_pages); + if (pages) + put_user_pages(pages, nr_pages); kfree(xbufs); kfree(pages); kfree(kbufs); -- 2.22.0