Messages in this thread | | | Date | Fri, 26 Apr 2024 08:45:44 +1000 | Subject | Re: [PATCH 3/4] vhost: Improve vhost_get_avail_head() | From | Gavin Shan <> |
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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@intel.com/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@intel.com> > | Closes: https://lore.kernel.org/oe-kbuild-all/202404260448.g7F06v7M-lkp@intel.com/ > > 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
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