@@ -456,18 +456,21 @@ static int __write_ring(struct pvcalls_data_intf *intf,
masked_cons = pvcalls_mask(cons, array_size);
if (masked_prod < masked_cons) {
- copy_from_iter(data->out + masked_prod, len, msg_iter);
+ len = copy_from_iter(data->out + masked_prod, len, msg_iter);
} else {
if (len > array_size - masked_prod) {
- copy_from_iter(data->out + masked_prod,
+ int ret = copy_from_iter(data->out + masked_prod,
array_size - masked_prod, msg_iter);
- copy_from_iter(data->out,
- len - (array_size - masked_prod),
- msg_iter);
+ if (ret != array_size - masked_prod) {
+ len = ret;
+ goto out;
+ }
+ len = ret + copy_from_iter(data->out, len - ret, msg_iter);
} else {
- copy_from_iter(data->out + masked_prod, len, msg_iter);
+ len = copy_from_iter(data->out + masked_prod, len, msg_iter);
}
}
+out:
/* write to ring before updating pointer */
virt_wmb();
intf->out_prod += len;
@@ -557,18 +560,21 @@ static int __read_ring(struct pvcalls_data_intf *intf,
len = size;
if (masked_prod > masked_cons) {
- copy_to_iter(data->in + masked_cons, len, msg_iter);
+ len = copy_to_iter(data->in + masked_cons, len, msg_iter);
} else {
if (len > (array_size - masked_cons)) {
- copy_to_iter(data->in + masked_cons,
+ int ret = copy_to_iter(data->in + masked_cons,
array_size - masked_cons, msg_iter);
- copy_to_iter(data->in,
- len - (array_size - masked_cons),
- msg_iter);
+ if (ret != array_size - masked_cons) {
+ len = ret;
+ goto out;
+ }
+ len = ret + copy_to_iter(data->in, len - ret, msg_iter);
} else {
- copy_to_iter(data->in + masked_cons, len, msg_iter);
+ len = copy_to_iter(data->in + masked_cons, len, msg_iter);
}
}
+out:
/* read data from the ring before increasing the index */
virt_mb();
if (!(flags & MSG_PEEK))
Check the return value of copy_from_iter in __write_ring and copy_to_iter in __read_ring. Update "len" accordingly. In the cases where we issue two consecutive copy_from_iter, or two consecutive copy_to_iter, first check return, then goto out if it is not what we expect. Signed-off-by: Stefano Stabellini <sstabellini@kernel.org> --- drivers/xen/pvcalls-front.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-)