[ This is really really ancient code. - dan ]
Hello Rupjyoti Sarmah,
The patch 3fb7933850fa: "powerpc/4xx: Adding PCIe MSI support" from
Mar 29, 2011, leads to the following static checker warning:
arch/powerpc/platforms/4xx/msi.c:100 ppc4xx_setup_msi_irqs()
warn: 'int_no >= 0' 'false' implies 'int_no < 0' is 'true'
arch/powerpc/platforms/4xx/msi.c
79 static int ppc4xx_setup_msi_irqs(struct pci_dev *dev, int nvec, int
type)
80 {
81 int int_no = -ENOMEM;
82 unsigned int virq;
83 struct msi_msg msg;
84 struct msi_desc *entry;
85 struct ppc4xx_msi *msi_data = &ppc4xx_msi;
86
87 dev_dbg(&dev->dev, "PCIE-MSI:%s called. vec %x type %d\n",
88 __func__, nvec, type);
89 if (type == PCI_CAP_ID_MSIX)
90 pr_debug("ppc4xx msi: MSI-X untested, trying
anyway.\n");
91
92 msi_data->msi_virqs = kmalloc((msi_irqs) * sizeof(int),
GFP_KERNEL);
93 if (!msi_data->msi_virqs)
94 return -ENOMEM;
95
96 for_each_pci_msi_entry(entry, dev) {
97 int_no = msi_bitmap_alloc_hwirqs(&msi_data->bitmap, 1);
98 if (int_no >= 0)
^^^^^^^^^^^
99 break;
100 if (int_no < 0) {
^^^^^^^^^^
Smatch is saying that this check could be removed, which is true.
101 pr_debug("%s: fail allocating msi interrupt\n",
102 __func__);
103 }
104 virq = irq_of_parse_and_map(msi_data->msi_dev, int_no);
^^^^^^
It doesn't seem right to pass negative indexes to irq_of_parse_and_map().
It could result in a read before the start of the array in
of_irq_parse_oldworld(), I think.
105 if (!virq) {
106 dev_err(&dev->dev, "%s: fail mapping irq\n",
__func__);
107 msi_bitmap_free_hwirqs(&msi_data->bitmap,
int_no, 1);
108 return -ENOSPC;
109 }
110 dev_dbg(&dev->dev, "%s: virq = %d\n", __func__, virq);
111
112 /* Setup msi address space */
113 msg.address_hi = msi_data->msi_addr_hi;
114 msg.address_lo = msi_data->msi_addr_lo;
115
116 irq_set_msi_desc(virq, entry);
117 msg.data = int_no;
118 pci_write_msi_msg(virq, &msg);
119 }
120 return 0;
121 }
regards,
dan carpenter
