On 4/26/24 06:42, kernel test robot wrote:> kernel test robot noticed the following build warnings:
[auto build test WARNING on mst-vhost/linux-next]
[also build test WARNING on linus/master v6.9-rc5 next-20240424]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Gavin-Shan/vhost-Drop-variable-last_avail_idx-in-vhost_get_vq_desc/20240423-112803
base: https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next
patch link: https://lore.kernel.org/r/20240423032407.262329-4-gshan%40redhat.com
patch subject: [PATCH 3/4] vhost: Improve vhost_get_avail_head()
config: i386-randconfig-141-20240426 (https://download.01.org/0day-ci/archive/20240426/202404260448.g7F06v7M-lkp@xxxxxxxxx/config)
compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202404260448.g7F06v7M-lkp@xxxxxxxxx/
smatch warnings:
drivers/vhost/vhost.c:2614 vhost_get_vq_desc() warn: unsigned 'head' is never less than zero.
drivers/vhost/vhost.c:2614 vhost_get_vq_desc() warn: error code type promoted to positive: 'head'
vim +/head +2614 drivers/vhost/vhost.c
2581
2582 /* This looks in the virtqueue and for the first available buffer, and converts
2583 * it to an iovec for convenient access. Since descriptors consist of some
2584 * number of output then some number of input descriptors, it's actually two
2585 * iovecs, but we pack them into one and note how many of each there were.
2586 *
2587 * This function returns the descriptor number found, or vq->num (which is
2588 * never a valid descriptor number) if none was found. A negative code is
2589 * returned on error. */
2590 int vhost_get_vq_desc(struct vhost_virtqueue *vq,
2591 struct iovec iov[], unsigned int iov_size,
2592 unsigned int *out_num, unsigned int *in_num,
2593 struct vhost_log *log, unsigned int *log_num)
2594 {
2595 struct vring_desc desc;
2596 unsigned int i, head, found = 0;
2597 int ret, access;
2598
2599 if (vq->avail_idx == vq->last_avail_idx) {
2600 ret = vhost_get_avail_idx(vq);
2601 if (unlikely(ret))
2602 return ret;
2603
2604 /* If there's nothing new since last we looked, return
2605 * invalid.
2606 */
2607 if (vq->avail_idx == vq->last_avail_idx)
2608 return vq->num;
2609 }
2610
2611 /* Grab the next descriptor number they're advertising, and increment
2612 * the index we've seen. */
2613 head = vhost_get_avail_head(vq);
2614 if (unlikely(head < 0))
2615 return head;
Thanks for the report. @head needs to be 'int' instead of 'unsigned int'
so that it can hold the error number from vhost_get_avail_head(). I would
give it more time to see if there are other review comments before I revise
it to fix it up.
Thanks,
Gavin
