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Message-Id: <20210104155704.001227950@linuxfoundation.org>
Date: Mon, 4 Jan 2021 16:57:15 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
Souptick Joarder <jrdr.linux@...il.com>,
John Hubbard <jhubbard@...dia.com>,
Juergen Gross <jgross@...e.com>,
David Vrabel <david.vrabel@...rix.com>,
Jinoh Kang <jinoh.kang.kr@...il.com>
Subject: [PATCH 4.19 12/35] xen/gntdev.c: Mark pages as dirty
From: Souptick Joarder <jrdr.linux@...il.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@...cle.com>
Signed-off-by: Souptick Joarder <jrdr.linux@...il.com>
Cc: John Hubbard <jhubbard@...dia.com>
Cc: Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc: Juergen Gross <jgross@...e.com>
Cc: David Vrabel <david.vrabel@...rix.com>
Cc: stable@...r.kernel.org
Link: https://lore.kernel.org/r/1599375114-32360-1-git-send-email-jrdr.linux@gmail.com
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@...cle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@...cle.com>
[jinoh: backport accounting for missing
commit 73b0140bf0fe ("mm/gup: change GUP fast to use flags rather than a write 'bool'")]
Signed-off-by: Jinoh Kang <jinoh.kang.kr@...il.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
drivers/xen/gntdev.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -842,17 +842,18 @@ 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, &page);
+ ret = get_user_pages_fast(addr, 1, batch->writeable, &page);
if (ret < 0)
return ret;
@@ -868,9 +869,13 @@ 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)
@@ -959,8 +964,9 @@ 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;
@@ -978,8 +984,9 @@ 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;
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