PCI: pciehp: Remove error checks when accessing PCIe Capability

There's not much point in checking the return value from every config space
access because the only likely errors are design-time things like unaligned
accesses or invalid register numbers.  The checking clutters the code
significantly, so this patch removes it.

No functional change.

Reference: http://lkml.kernel.org/r/CA+55aFzP4xEbcNmZ+MS0SQ3LrULzSq+dBiT_X9U-bPpR-Ukgrw@mail.gmail.com
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 53bb5501d19971f5f7961a66df00f7408bb8b170..6afdd23582273dd4abf093b5c236d9daa7b8533e 100644 (file)
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -112,10 +112,10 @@ static int pcie_poll_cmd(struct controller *ctrl)
 {
        struct pci_dev *pdev = ctrl_dev(ctrl);
        u16 slot_status;
-       int err, timeout = 1000;
+       int timeout = 1000;
 
-       err = pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
-       if (!err && (slot_status & PCI_EXP_SLTSTA_CC)) {
+       pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
+       if (slot_status & PCI_EXP_SLTSTA_CC) {
                pcie_capability_write_word(pdev, PCI_EXP_SLTSTA,
                                           PCI_EXP_SLTSTA_CC);
                return 1;
@@ -123,9 +123,8 @@ static int pcie_poll_cmd(struct controller *ctrl)
        while (timeout > 0) {
                msleep(10);
                timeout -= 10;
-               err = pcie_capability_read_word(pdev, PCI_EXP_SLTSTA,
-                                               &slot_status);
-               if (!err && (slot_status & PCI_EXP_SLTSTA_CC)) {
+               pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
+               if (slot_status & PCI_EXP_SLTSTA_CC) {
                        pcie_capability_write_word(pdev, PCI_EXP_SLTSTA,
                                                   PCI_EXP_SLTSTA_CC);
                        return 1;
@@ -157,19 +156,12 @@ static void pcie_wait_cmd(struct controller *ctrl, int poll)
 static int pcie_write_cmd(struct controller *ctrl, u16 cmd, u16 mask)
 {
        struct pci_dev *pdev = ctrl_dev(ctrl);
-       int retval = 0;
        u16 slot_status;
        u16 slot_ctrl;
 
        mutex_lock(&ctrl->ctrl_lock);
 
-       retval = pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
-       if (retval) {
-               ctrl_err(ctrl, "%s: Cannot read SLOTSTATUS register\n",
-                        __func__);
-               goto out;
-       }
-
+       pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
        if (slot_status & PCI_EXP_SLTSTA_CC) {
                if (!ctrl->no_cmd_complete) {
                        /*
@@ -193,24 +185,17 @@ static int pcie_write_cmd(struct controller *ctrl, u16 cmd, u16 mask)
                }
        }
 
-       retval = pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &slot_ctrl);
-       if (retval) {
-               ctrl_err(ctrl, "%s: Cannot read SLOTCTRL register\n", __func__);
-               goto out;
-       }
-
+       pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &slot_ctrl);
        slot_ctrl &= ~mask;
        slot_ctrl |= (cmd & mask);
        ctrl->cmd_busy = 1;
        smp_mb();
-       retval = pcie_capability_write_word(pdev, PCI_EXP_SLTCTL, slot_ctrl);
-       if (retval)
-               ctrl_err(ctrl, "Cannot write to SLOTCTRL register\n");
+       pcie_capability_write_word(pdev, PCI_EXP_SLTCTL, slot_ctrl);
 
        /*
         * Wait for command completion.
         */
-       if (!retval && !ctrl->no_cmd_complete) {
+       if (!ctrl->no_cmd_complete) {
                int poll = 0;
                /*
                 * if hotplug interrupt is not enabled or command
@@ -222,20 +207,17 @@ static int pcie_write_cmd(struct controller *ctrl, u16 cmd, u16 mask)
                        poll = 1;
                 pcie_wait_cmd(ctrl, poll);
        }
- out:
        mutex_unlock(&ctrl->ctrl_lock);
-       return retval;
+       return 0;
 }
 
 static bool check_link_active(struct controller *ctrl)
 {
        struct pci_dev *pdev = ctrl_dev(ctrl);
-       bool ret = false;
        u16 lnk_status;
+       bool ret;
 
-       if (pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status))
-               return ret;
-
+       pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
        ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA);
 
        if (ret)
@@ -299,9 +281,8 @@ static bool pci_bus_check_dev(struct pci_bus *bus, int devfn)
 int pciehp_check_link_status(struct controller *ctrl)
 {
        struct pci_dev *pdev = ctrl_dev(ctrl);
+       bool found;
        u16 lnk_status;
-       int retval = 0;
-       bool found = false;
 
         /*
          * Data Link Layer Link Active Reporting must be capable for
@@ -318,53 +299,37 @@ int pciehp_check_link_status(struct controller *ctrl)
        found = pci_bus_check_dev(ctrl->pcie->port->subordinate,
                                        PCI_DEVFN(0, 0));
 
-       retval = pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
-       if (retval) {
-               ctrl_err(ctrl, "Cannot read LNKSTATUS register\n");
-               return retval;
-       }
-
+       pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
        ctrl_dbg(ctrl, "%s: lnk_status = %x\n", __func__, lnk_status);
        if ((lnk_status & PCI_EXP_LNKSTA_LT) ||
            !(lnk_status & PCI_EXP_LNKSTA_NLW)) {
                ctrl_err(ctrl, "Link Training Error occurs \n");
-               retval = -1;
-               return retval;
+               return -1;
        }
 
        pcie_update_link_speed(ctrl->pcie->port->subordinate, lnk_status);
 
-       if (!found && !retval)
-               retval = -1;
+       if (!found)
+               return -1;
 
-       return retval;
+       return 0;
 }
 
 static int __pciehp_link_set(struct controller *ctrl, bool enable)
 {
        struct pci_dev *pdev = ctrl_dev(ctrl);
        u16 lnk_ctrl;
-       int retval = 0;
 
-       retval = pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &lnk_ctrl);
-       if (retval) {
-               ctrl_err(ctrl, "Cannot read LNKCTRL register\n");
-               return retval;
-       }
+       pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &lnk_ctrl);
 
        if (enable)
                lnk_ctrl &= ~PCI_EXP_LNKCTL_LD;
        else
                lnk_ctrl |= PCI_EXP_LNKCTL_LD;
 
-       retval = pcie_capability_write_word(pdev, PCI_EXP_LNKCTL, lnk_ctrl);
-       if (retval) {
-               ctrl_err(ctrl, "Cannot write LNKCTRL register\n");
-               return retval;
-       }
+       pcie_capability_write_word(pdev, PCI_EXP_LNKCTL, lnk_ctrl);
        ctrl_dbg(ctrl, "%s: lnk_ctrl = %x\n", __func__, lnk_ctrl);
-
-       return retval;
+       return 0;
 }
 
 static int pciehp_link_enable(struct controller *ctrl)
@@ -383,14 +348,8 @@ int pciehp_get_attention_status(struct slot *slot, u8 *status)
        struct pci_dev *pdev = ctrl_dev(ctrl);
        u16 slot_ctrl;
        u8 atten_led_state;
-       int retval = 0;
-
-       retval = pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &slot_ctrl);
-       if (retval) {
-               ctrl_err(ctrl, "%s: Cannot read SLOTCTRL register\n", __func__);
-               return retval;
-       }
 
+       pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &slot_ctrl);
        ctrl_dbg(ctrl, "%s: SLOTCTRL %x, value read %x\n", __func__,
                 pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL, slot_ctrl);
 
@@ -423,13 +382,8 @@ int pciehp_get_power_status(struct slot *slot, u8 *status)
        struct pci_dev *pdev = ctrl_dev(ctrl);
        u16 slot_ctrl;
        u8 pwr_state;
-       int     retval = 0;
 
-       retval = pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &slot_ctrl);
-       if (retval) {
-               ctrl_err(ctrl, "%s: Cannot read SLOTCTRL register\n", __func__);
-               return retval;
-       }
+       pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &slot_ctrl);
        ctrl_dbg(ctrl, "%s: SLOTCTRL %x value read %x\n", __func__,
                 pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL, slot_ctrl);
 
@@ -447,55 +401,35 @@ int pciehp_get_power_status(struct slot *slot, u8 *status)
                break;
        }
 
-       return retval;
+       return 0;
 }
 
 int pciehp_get_latch_status(struct slot *slot, u8 *status)
 {
-       struct controller *ctrl = slot->ctrl;
-       struct pci_dev *pdev = ctrl_dev(ctrl);
+       struct pci_dev *pdev = ctrl_dev(slot->ctrl);
        u16 slot_status;
-       int retval;
 
-       retval = pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
-       if (retval) {
-               ctrl_err(ctrl, "%s: Cannot read SLOTSTATUS register\n",
-                        __func__);
-               return retval;
-       }
+       pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
        *status = !!(slot_status & PCI_EXP_SLTSTA_MRLSS);
        return 0;
 }
 
 int pciehp_get_adapter_status(struct slot *slot, u8 *status)
 {
-       struct controller *ctrl = slot->ctrl;
-       struct pci_dev *pdev = ctrl_dev(ctrl);
+       struct pci_dev *pdev = ctrl_dev(slot->ctrl);
        u16 slot_status;
-       int retval;
 
-       retval = pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
-       if (retval) {
-               ctrl_err(ctrl, "%s: Cannot read SLOTSTATUS register\n",
-                        __func__);
-               return retval;
-       }
+       pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
        *status = !!(slot_status & PCI_EXP_SLTSTA_PDS);
        return 0;
 }
 
 int pciehp_query_power_fault(struct slot *slot)
 {
-       struct controller *ctrl = slot->ctrl;
-       struct pci_dev *pdev = ctrl_dev(ctrl);
+       struct pci_dev *pdev = ctrl_dev(slot->ctrl);
        u16 slot_status;
-       int retval;
 
-       retval = pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
-       if (retval) {
-               ctrl_err(ctrl, "Cannot check for power fault\n");
-               return retval;
-       }
+       pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
        return !!(slot_status & PCI_EXP_SLTSTA_PFD);
 }
 
@@ -570,25 +504,13 @@ int pciehp_power_on_slot(struct slot * slot)
        u16 slot_cmd;
        u16 cmd_mask;
        u16 slot_status;
-       int retval = 0;
+       int retval;
 
        /* Clear sticky power-fault bit from previous power failures */
-       retval = pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
-       if (retval) {
-               ctrl_err(ctrl, "%s: Cannot read SLOTSTATUS register\n",
-                        __func__);
-               return retval;
-       }
+       pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
        slot_status &= PCI_EXP_SLTSTA_PFD;
-       if (slot_status) {
-               retval = pcie_capability_write_word(pdev, PCI_EXP_SLTSTA, slot_status);
-               if (retval) {
-                       ctrl_err(ctrl,
-                                "%s: Cannot write to SLOTSTATUS register\n",
-                                __func__);
-                       return retval;
-               }
-       }
+       if (slot_status)
+               pcie_capability_write_word(pdev, PCI_EXP_SLTSTA, slot_status);
        ctrl->power_fault_detected = 0;
 
        slot_cmd = POWER_ON;
@@ -649,12 +571,7 @@ static irqreturn_t pcie_isr(int irq, void *dev_id)
         */
        intr_loc = 0;
        do {
-               if (pcie_capability_read_word(pdev, PCI_EXP_SLTSTA,
-                                             &detected)) {
-                       ctrl_err(ctrl, "%s: Cannot read SLOTSTATUS\n",
-                                __func__);
-                       return IRQ_NONE;
-               }
+               pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &detected);
 
                detected &= (PCI_EXP_SLTSTA_ABP | PCI_EXP_SLTSTA_PFD |
                             PCI_EXP_SLTSTA_MRLSC | PCI_EXP_SLTSTA_PDC |
@@ -663,13 +580,9 @@ static irqreturn_t pcie_isr(int irq, void *dev_id)
                intr_loc |= detected;
                if (!intr_loc)
                        return IRQ_NONE;
-               if (detected &&
-                   pcie_capability_write_word(pdev, PCI_EXP_SLTSTA,
-                                              intr_loc)) {
-                       ctrl_err(ctrl, "%s: Cannot write to SLOTSTATUS\n",
-                                __func__);
-                       return IRQ_NONE;
-               }
+               if (detected)
+                       pcie_capability_write_word(pdev, PCI_EXP_SLTSTA,
+                                                  intr_loc);
        } while (detected);
 
        ctrl_dbg(ctrl, "%s: intr_loc %x\n", __func__, intr_loc);
@@ -894,11 +807,7 @@ struct controller *pcie_init(struct pcie_device *dev)
                goto abort;
        }
        ctrl->pcie = dev;
-       if (pcie_capability_read_dword(pdev, PCI_EXP_SLTCAP, &slot_cap)) {
-               ctrl_err(ctrl, "Cannot read SLOTCAP register\n");
-               goto abort_ctrl;
-       }
-
+       pcie_capability_read_dword(pdev, PCI_EXP_SLTCAP, &slot_cap);
        ctrl->slot_cap = slot_cap;
        mutex_init(&ctrl->ctrl_lock);
        init_waitqueue_head(&ctrl->queue);
@@ -914,18 +823,14 @@ struct controller *pcie_init(struct pcie_device *dev)
            ctrl->no_cmd_complete = 1;
 
         /* Check if Data Link Layer Link Active Reporting is implemented */
-        if (pcie_capability_read_dword(pdev, PCI_EXP_LNKCAP, &link_cap)) {
-                ctrl_err(ctrl, "%s: Cannot read LNKCAP register\n", __func__);
-                goto abort_ctrl;
-        }
+        pcie_capability_read_dword(pdev, PCI_EXP_LNKCAP, &link_cap);
         if (link_cap & PCI_EXP_LNKCAP_DLLLARC) {
                 ctrl_dbg(ctrl, "Link Active Reporting supported\n");
                 ctrl->link_active_reporting = 1;
         }
 
        /* Clear all remaining event bits in Slot Status register */
-       if (pcie_capability_write_word(pdev, PCI_EXP_SLTSTA, 0x1f))
-               goto abort_ctrl;
+       pcie_capability_write_word(pdev, PCI_EXP_SLTSTA, 0x1f);
 
        /* Disable software notification */
        pcie_disable_notification(ctrl);