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| author | Souptick Joarder <jrdr.linux@gmail.com> | 2020-09-06 12:21:53 +0530 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-11-01 12:47:09 +0100 |
| commit | 4683c5407bd5ed473063993b7593f5d8084daceb (patch) | |
| tree | 18543b2466157090262020de107b79278e017a87 | |
| parent | 95528c8042a412a77e4769a2ff2abf31fee08b0d (diff) | |
| download | linux-stable-4683c5407bd5ed473063993b7593f5d8084daceb.tar.gz linux-stable-4683c5407bd5ed473063993b7593f5d8084daceb.tar.bz2 linux-stable-4683c5407bd5ed473063993b7593f5d8084daceb.zip | |
xen/gntdev.c: Mark pages as dirty
commit 779055842da5b2e508f3ccf9a8153cb1f704f566 upstream.
There seems to be a bug in the original code when gntdev_get_page()
is called with writeable=true then the page needs to be marked dirty
before being put.
To address this, a bool writeable is added in gnt_dev_copy_batch, set
it in gntdev_grant_copy_seg() (and drop `writeable` argument to
gntdev_get_page()) and then, based on batch->writeable, use
set_page_dirty_lock().
Fixes: a4cdb556cae0 (xen/gntdev: add ioctl for grant copy)
Suggested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/1599375114-32360-1-git-send-email-jrdr.linux@gmail.com
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/xen/gntdev.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index 64a9025a87be..1f32db7b72b2 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -720,17 +720,18 @@ struct gntdev_copy_batch { s16 __user *status[GNTDEV_COPY_BATCH]; unsigned int nr_ops; unsigned int nr_pages; + bool writeable; }; static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt, - bool writeable, unsigned long *gfn) + unsigned long *gfn) { unsigned long addr = (unsigned long)virt; struct page *page; unsigned long xen_pfn; int ret; - ret = get_user_pages_fast(addr, 1, writeable ? FOLL_WRITE : 0, &page); + ret = get_user_pages_fast(addr, 1, batch->writeable ? FOLL_WRITE : 0, &page); if (ret < 0) return ret; @@ -746,9 +747,13 @@ static void gntdev_put_pages(struct gntdev_copy_batch *batch) { unsigned int i; - for (i = 0; i < batch->nr_pages; i++) + for (i = 0; i < batch->nr_pages; i++) { + if (batch->writeable && !PageDirty(batch->pages[i])) + set_page_dirty_lock(batch->pages[i]); put_page(batch->pages[i]); + } batch->nr_pages = 0; + batch->writeable = false; } static int gntdev_copy(struct gntdev_copy_batch *batch) @@ -837,8 +842,9 @@ static int gntdev_grant_copy_seg(struct gntdev_copy_batch *batch, virt = seg->source.virt + copied; off = (unsigned long)virt & ~XEN_PAGE_MASK; len = min(len, (size_t)XEN_PAGE_SIZE - off); + batch->writeable = false; - ret = gntdev_get_page(batch, virt, false, &gfn); + ret = gntdev_get_page(batch, virt, &gfn); if (ret < 0) return ret; @@ -856,8 +862,9 @@ static int gntdev_grant_copy_seg(struct gntdev_copy_batch *batch, virt = seg->dest.virt + copied; off = (unsigned long)virt & ~XEN_PAGE_MASK; len = min(len, (size_t)XEN_PAGE_SIZE - off); + batch->writeable = true; - ret = gntdev_get_page(batch, virt, true, &gfn); + ret = gntdev_get_page(batch, virt, &gfn); if (ret < 0) return ret; |