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List: linux-stable-commits
Subject: Patch "xen/gntdev.c: Mark pages as dirty" has been added to the 5.9-stable tree
From: <gregkh () linuxfoundation ! org>
Date: 2020-10-31 10:24:54
Message-ID: 1604139894117180 () kroah ! com
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This is a note to let you know that I've just added the patch titled
xen/gntdev.c: Mark pages as dirty
to the 5.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xen-gntdev.c-mark-pages-as-dirty.patch
and it can be found in the queue-5.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.
From 779055842da5b2e508f3ccf9a8153cb1f704f566 Mon Sep 17 00:00:00 2001
From: Souptick Joarder <jrdr.linux@gmail.com>
Date: Sun, 6 Sep 2020 12:21:53 +0530
Subject: xen/gntdev.c: Mark pages as dirty
From: Souptick Joarder <jrdr.linux@gmail.com>
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>
---
drivers/xen/gntdev.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
--- 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 gntd
{
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
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
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;
Patches currently in stable-queue which might be from jrdr.linux@gmail.com are
queue-5.9/xen-gntdev.c-mark-pages-as-dirty.patch
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