tree: https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git pci/enumeration head: 4ca0362aafeb3b357f85ae3121328edbf979fc9a commit: a88de411b5ed7ff28f3cac96581eb3b5d5bf8b61 [5/15] PCI: Add pcie_bandwidth_available() to compute bandwidth available to device smatch warnings: drivers/pci/pci.c:5190 pcie_bandwidth_available() warn: variable dereferenced before check 'speed' (see line 5171) drivers/pci/pci.c:5192 pcie_bandwidth_available() warn: variable dereferenced before check 'width' (see line 5172) # https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git/commit/?id=a88de411b5ed7ff28f3cac96581eb3b5d5bf8b61 git remote add pci https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git git remote update pci git checkout a88de411b5ed7ff28f3cac96581eb3b5d5bf8b61 vim +/speed +5190 drivers/pci/pci.c 81377c8d Jacob Keller 2013-07-31 5148 81377c8d Jacob Keller 2013-07-31 5149 /** a88de411 Tal Gilboa 2018-03-30 5150 * pcie_bandwidth_available - determine minimum link settings of a PCIe a88de411 Tal Gilboa 2018-03-30 5151 * device and its bandwidth limitation a88de411 Tal Gilboa 2018-03-30 5152 * @dev: PCI device to query a88de411 Tal Gilboa 2018-03-30 5153 * @limiting_dev: storage for device causing the bandwidth limitation a88de411 Tal Gilboa 2018-03-30 5154 * @speed: storage for speed of limiting device a88de411 Tal Gilboa 2018-03-30 5155 * @width: storage for width of limiting device a88de411 Tal Gilboa 2018-03-30 5156 * a88de411 Tal Gilboa 2018-03-30 5157 * Walk up the PCI device chain and find the point where the minimum a88de411 Tal Gilboa 2018-03-30 5158 * bandwidth is available. Return the bandwidth available there and (if a88de411 Tal Gilboa 2018-03-30 5159 * limiting_dev, speed, and width pointers are supplied) information about a88de411 Tal Gilboa 2018-03-30 5160 * that point. a88de411 Tal Gilboa 2018-03-30 5161 */ a88de411 Tal Gilboa 2018-03-30 5162 u32 pcie_bandwidth_available(struct pci_dev *dev, struct pci_dev **limiting_dev, a88de411 Tal Gilboa 2018-03-30 5163 enum pci_bus_speed *speed, a88de411 Tal Gilboa 2018-03-30 5164 enum pcie_link_width *width) a88de411 Tal Gilboa 2018-03-30 5165 { a88de411 Tal Gilboa 2018-03-30 5166 u16 lnksta; a88de411 Tal Gilboa 2018-03-30 5167 enum pci_bus_speed next_speed; a88de411 Tal Gilboa 2018-03-30 5168 enum pcie_link_width next_width; a88de411 Tal Gilboa 2018-03-30 5169 u32 bw, next_bw; a88de411 Tal Gilboa 2018-03-30 5170 a88de411 Tal Gilboa 2018-03-30 @5171 *speed = PCI_SPEED_UNKNOWN; a88de411 Tal Gilboa 2018-03-30 @5172 *width = PCIE_LNK_WIDTH_UNKNOWN; ^^^^^^ a88de411 Tal Gilboa 2018-03-30 5173 bw = 0; a88de411 Tal Gilboa 2018-03-30 5174 a88de411 Tal Gilboa 2018-03-30 5175 while (dev) { a88de411 Tal Gilboa 2018-03-30 5176 pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &lnksta); a88de411 Tal Gilboa 2018-03-30 5177 a88de411 Tal Gilboa 2018-03-30 5178 next_speed = pcie_link_speed[lnksta & PCI_EXP_LNKSTA_CLS]; a88de411 Tal Gilboa 2018-03-30 5179 next_width = (lnksta & PCI_EXP_LNKSTA_NLW) >> a88de411 Tal Gilboa 2018-03-30 5180 PCI_EXP_LNKSTA_NLW_SHIFT; a88de411 Tal Gilboa 2018-03-30 5181 a88de411 Tal Gilboa 2018-03-30 5182 next_bw = next_width * PCIE_SPEED2MBS_ENC(next_speed); a88de411 Tal Gilboa 2018-03-30 5183 a88de411 Tal Gilboa 2018-03-30 5184 /* Check if current device limits the total bandwidth */ a88de411 Tal Gilboa 2018-03-30 5185 if (!bw || next_bw <= bw) { a88de411 Tal Gilboa 2018-03-30 5186 bw = next_bw; a88de411 Tal Gilboa 2018-03-30 5187 a88de411 Tal Gilboa 2018-03-30 5188 if (limiting_dev) a88de411 Tal Gilboa 2018-03-30 5189 *limiting_dev = dev; a88de411 Tal Gilboa 2018-03-30 @5190 if (speed) a88de411 Tal Gilboa 2018-03-30 5191 *speed = next_speed; a88de411 Tal Gilboa 2018-03-30 @5192 if (width) ^^^^^ a88de411 Tal Gilboa 2018-03-30 5193 *width = next_width; a88de411 Tal Gilboa 2018-03-30 5194 } a88de411 Tal Gilboa 2018-03-30 5195 a88de411 Tal Gilboa 2018-03-30 5196 dev = pci_upstream_bridge(dev); a88de411 Tal Gilboa 2018-03-30 5197 } a88de411 Tal Gilboa 2018-03-30 5198 a88de411 Tal Gilboa 2018-03-30 5199 return bw; a88de411 Tal Gilboa 2018-03-30 5200 } a88de411 Tal Gilboa 2018-03-30 5201 EXPORT_SYMBOL(pcie_bandwidth_available); a88de411 Tal Gilboa 2018-03-30 5202 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
