[PATCH 5.19 058/207] xen/xenbus: fix xenbus_setup_ring()

Greg Kroah-Hartman
2022-09-26T11:40:51Z

From: Juergen Gross <jgross@suse.com>

commit ce6b8ccdef959ba86b2711e090e84a987a000bf7 upstream.

Commit 4573240f0764 ("xen/xenbus: eliminate xenbus_grant_ring()")
introduced an error for initialization of multi-page rings.

Cc: stable@vger.kernel.org
Fixes: 4573240f0764 ("xen/xenbus: eliminate xenbus_grant_ring()")
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/xen/xenbus/xenbus_client.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index d5f3f763717e..d4b251925796 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -382,9 +382,10 @@ int xenbus_setup_ring(struct xenbus_device *dev, gfp_t gfp, void **vaddr,
unsigned long ring_size = nr_pages * XEN_PAGE_SIZE;
grant_ref_t gref_head;
unsigned int i;
+ void *addr;
int ret;

- *vaddr = alloc_pages_exact(ring_size, gfp | __GFP_ZERO);
+ addr = *vaddr = alloc_pages_exact(ring_size, gfp | __GFP_ZERO);
if (!*vaddr) {
ret = -ENOMEM;
goto err;
@@ -401,13 +402,15 @@ int xenbus_setup_ring(struct xenbus_device *dev, gfp_t gfp, void **vaddr,
unsigned long gfn;

if (is_vmalloc_addr(*vaddr))
- gfn = pfn_to_gfn(vmalloc_to_pfn(vaddr[i]));
+ gfn = pfn_to_gfn(vmalloc_to_pfn(addr));
else
- gfn = virt_to_gfn(vaddr[i]);
+ gfn = virt_to_gfn(addr);

grefs[i] = gnttab_claim_grant_reference(&gref_head);
gnttab_grant_foreign_access_ref(grefs[i], dev->otherend_id,
gfn, 0);
+
+ addr += XEN_PAGE_SIZE;
}

return 0;
--
2.37.3