Hello Daniel Jurgens,
The patch e45678973dcb: "{net, IB}/mlx4: Initialize CQ buffers in the
driver when possible" from Nov 21, 2018, leads to the following
static checker warning:
drivers/net/ethernet/mellanox/mlx4/cq.c:322 mlx4_init_user_cqes()
warn: maybe return -EFAULT instead of the bytes remaining?
drivers/net/ethernet/mellanox/mlx4/cq.c
290 static int mlx4_init_user_cqes(void *buf, int entries, int cqe_size)
291 {
292 int entries_per_copy = PAGE_SIZE / cqe_size;
293 void *init_ents;
294 int err = 0;
295 int i;
296
297 init_ents = kmalloc(PAGE_SIZE, GFP_KERNEL);
298 if (!init_ents)
299 return -ENOMEM;
300
301 /* Populate a list of CQ entries to reduce the number of
302 * copy_to_user calls. 0xcc is the initialization value
303 * required by the FW.
304 */
305 memset(init_ents, 0xcc, PAGE_SIZE);
306
307 if (entries_per_copy < entries) {
308 for (i = 0; i < entries / entries_per_copy; i++) {
309 err = copy_to_user(buf, init_ents, PAGE_SIZE);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
310 if (err)
311 goto out;
312
313 buf += PAGE_SIZE;
314 }
315 } else {
316 err = copy_to_user(buf, init_ents, entries * cqe_size);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
copy_to_user() returns the number of bytes which we weren't able to
copy.
I looked at the error handling in the caller, and it's really weird to
me what's going on there... If these copies fail we set op_mod to zero?
317 }
318
319 out:
320 kfree(init_ents);
321
322 return err;
323 }
regards,
dan carpenter
