[meghadey-crypto:d_msix 1/1] drivers/pci/msi.c:1040 __pci_enable_msix() warn: unsigned 'dev->msix_vec_cnt' is never less than zero.

[kernel test robot]

tree:   https://github.com/meghadey/crypto d_msix
head:   00c6841830531fd32a943ceb9838af5a95a00524
commit: 00c6841830531fd32a943ceb9838af5a95a00524 [1/1] PCI/MSI: Dynamic allocation of MSI-X vectors
config: s390-randconfig-m031-20210830 (attached as .config)
compiler: s390-linux-gcc (GCC) 11.2.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

smatch warnings:
drivers/pci/msi.c:1040 __pci_enable_msix() warn: unsigned 'dev->msix_vec_cnt' is never less than zero.

vim +1040 drivers/pci/msi.c

  1029	
  1030	static int __pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries,
  1031				     int nvec, struct irq_affinity *affd, int flags)
  1032	{
  1033		int i, j, ret;
  1034	
  1035		if (!pci_msi_supported(dev, nvec) || dev->current_state != PCI_D0)
  1036			return -EINVAL;
  1037	
  1038		dev->msix_vec_cnt = pci_msix_vec_count(dev);
  1039		if (!dev->msix_enabled) {
> 1040			if (dev->msix_vec_cnt < 0)
  1041				return dev->msix_vec_cnt;
  1042			dev->msix_map = kcalloc(BITS_TO_LONGS(dev->msix_vec_cnt), sizeof(long), GFP_KERNEL);
  1043			if (!dev->msix_map)
  1044				return -ENOMEM;
  1045		}
  1046	
  1047		if (nvec > (dev->msix_vec_cnt - dev->msix_alloc_cnt) && !(flags & PCI_IRQ_VIRTUAL))
  1048			return dev->msix_vec_cnt - dev->msix_alloc_cnt;
  1049	
  1050		if (entries) {
  1051			/* Check for any invalid entries */
  1052			for (i = 0; i < nvec; i++) {
  1053				if (entries[i].entry >= dev->msix_vec_cnt)
  1054					return -EINVAL;		/* invalid entry */
  1055				for (j = i + 1; j < nvec; j++) {
  1056					if (entries[i].entry == entries[j].entry)
  1057						return -EINVAL;	/* duplicate entry */
  1058				}
  1059			}
  1060		}
  1061	
  1062		/* Check whether driver already requested for MSI IRQ */
  1063		if (dev->msi_enabled) {
  1064			pci_info(dev, "can't enable MSI-X (MSI IRQ already assigned)\n");
  1065			return -EINVAL;
  1066		}
  1067	
  1068		if (!dev->msix_enabled) {
  1069			ret = msix_setup_table(dev);
  1070			if (ret)
  1071				return ret;
  1072		}
  1073	
  1074		return msix_setup_irqs(dev, entries, nvec, affd);
  1075	}
  1076	

---
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Attachment: .config.gz
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