3 files changed, 16 insertions, 3 deletions

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 7edd5c307446..25f0bc659164 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -19,6 +19,7 @@
 #include <linux/cpu.h>
 #include <linux/pm_runtime.h>
 #include <linux/suspend.h>
+#include <linux/kexec.h>
 #include "pci.h"
 
 struct pci_dynid {
@@ -415,12 +416,17 @@ static void pci_device_shutdown(struct device *dev)
         pci_msi_shutdown(pci_dev);
         pci_msix_shutdown(pci_dev);
 
+#ifdef CONFIG_KEXEC
         /*
-         * Turn off Bus Master bit on the device to tell it to not
-         * continue to do DMA. Don't touch devices in D3cold or unknown states.
+         * If this is a kexec reboot, turn off Bus Master bit on the
+         * device to tell it to not continue to do DMA. Don't touch
+         * devices in D3cold or unknown states.
+         * If it is not a kexec reboot, firmware will hit the PCI
+         * devices with big hammer and stop their DMA any way.
          */
-        if (pci_dev->current_state <= PCI_D3hot)
+        if (kexec_in_progress && (pci_dev->current_state <= PCI_D3hot))
                 pci_clear_master(pci_dev);
+#endif
 }
 
 #ifdef CONFIG_PM
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index d78d28a733b1..5fd33dc1fe3a 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -198,6 +198,9 @@ extern u32 vmcoreinfo_note[VMCOREINFO_NOTE_SIZE/4];
 extern size_t vmcoreinfo_size;
 extern size_t vmcoreinfo_max_size;
 
+/* flag to track if kexec reboot is in progress */
+extern bool kexec_in_progress;
+
 int __init parse_crashkernel(char *cmdline, unsigned long long system_ram,
                 unsigned long long *crash_size, unsigned long long *crash_base);
 int parse_crashkernel_high(char *cmdline, unsigned long long system_ram,
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 490afc03627e..d0d8fca54065 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -47,6 +47,9 @@ u32 vmcoreinfo_note[VMCOREINFO_NOTE_SIZE/4];
 size_t vmcoreinfo_size;
 size_t vmcoreinfo_max_size = sizeof(vmcoreinfo_data);
 
+/* Flag to indicate we are going to kexec a new kernel */
+bool kexec_in_progress = false;
+
 /* Location of the reserved area for the crash kernel */
 struct resource crashk_res = {
         .name  = "Crash kernel",
@@ -1675,6 +1678,7 @@ int kernel_kexec(void)
         } else
 #endif
         {
+                kexec_in_progress = true;
                 kernel_restart_prepare(NULL);
                 printk(KERN_EMERG "Starting new kernel\n");
                 machine_shutdown();