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authorSouptick Joarder <jrdr.linux@gmail.com>2020-09-06 09:51:53 +0300
committerBoris Ostrovsky <boris.ostrovsky@oracle.com>2020-10-05 02:39:18 +0300
commit779055842da5b2e508f3ccf9a8153cb1f704f566 (patch)
treeed5d0d89d9207c4ae3e9a61d1753216bcd6895ef /drivers/xen/gntdev.c
parent549738f15da0e5a00275977623be199fbbf7df50 (diff)
downloadlinux-779055842da5b2e508f3ccf9a8153cb1f704f566.tar.xz
xen/gntdev.c: Mark pages as dirty
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>
Diffstat (limited to 'drivers/xen/gntdev.c')
-rw-r--r--drivers/xen/gntdev.c17
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;