1 files changed, 16 insertions, 2 deletions

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 7cd417e94058..6f45a73c6e9f 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3202,8 +3202,6 @@ int pcie_set_readrq(struct pci_dev *dev, int rq)
         if (rq < 128 || rq > 4096 || !is_power_of_2(rq))
                 goto out;
 
-        v = (ffs(rq) - 8) << 12;
-
         cap = pci_pcie_cap(dev);
         if (!cap)
                 goto out;
@@ -3211,6 +3209,22 @@ int pcie_set_readrq(struct pci_dev *dev, int rq)
         err = pci_read_config_word(dev, cap + PCI_EXP_DEVCTL, &ctl);
         if (err)
                 goto out;
+        /*
+         * If using the "performance" PCIe config, we clamp the
+         * read rq size to the max packet size to prevent the
+         * host bridge generating requests larger than we can
+         * cope with
+         */
+        if (pcie_bus_config == PCIE_BUS_PERFORMANCE) {
+                int mps = pcie_get_mps(dev);
+
+                if (mps < 0)
+                        return mps;
+                if (mps < rq)
+                        rq = mps;
+        }
+
+        v = (ffs(rq) - 8) << 12;
 
         if ((ctl & PCI_EXP_DEVCTL_READRQ) != v) {
                 ctl &= ~PCI_EXP_DEVCTL_READRQ;