On 2024/3/7 2:43, John Garry wrote:
As an aside, could libsas - and your changes here - be simpler if we
changed smp_execute_task() like this:
static int smp_execute_task(struct domain_device *dev, void *req /* can
be on the stack */, int req_size,
void *resp /* can be on the stack */, int resp_size)
{
struct scatterlist req_sg;
struct scatterlist resp_sg;
int ret;
void *_req = kmemdup(req, req_size, GFP_KERNEL);
void *_resp = alloc_smp_resp(resp_size);
if (!_req || !resp)
return -ENOMEM;
sg_init_one(&req_sg, _req, req_size);
sg_init_one(&resp_sg, _resp, resp_size);
ret = smp_execute_task_sg(dev, &req_sg, &resp_sg);
memcpy(resp, _resp, resp_size);
kfree(_req);
kfree(_resp);
return ret;
}
We need to use alloc_smp_resp() and alloc_smp_req() as we can't allocate
these memories on the stack for calling sg_init_one(). But if we changed
smp_execute_task() to memcpy from/to data on the stack, it might make
callers simpler. I'm not sure.
Maybe simpler. I have not check all the length of these buffers, but
there is still a risk of stack overflow if the buffer on stack is too
large.
Thanks,
Jason
