[PATCH v8 1/3] kexec: Refactor kexec_in_progress into a function

[Ricardo Ribalda <ribalda@xxxxxxxxxxxx>]

Drivers running .shutdown() might want to behave differently during
kexec.

Convert kexec_in_progress into a function and export it, so it can be
used by drivers that are either built-in or modules.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 83bfc7e793b5 ("ASoC: SOF: core: unregister clients and machine drivers 
in .shutdown")
Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
---
 arch/powerpc/platforms/pseries/vio.c |  2 +-
 arch/x86/kernel/cpu/mshyperv.c       |  6 +++---
 arch/x86/xen/enlighten_hvm.c         |  2 +-
 drivers/firmware/efi/efi.c           |  2 +-
 drivers/pci/pci-driver.c             |  2 +-
 include/linux/kexec.h                |  5 ++---
 kernel/kexec_core.c                  | 12 ++++++++++--
 7 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/vio.c 
b/arch/powerpc/platforms/pseries/vio.c
index 00ecac2c205b..923f9a36b992 100644
--- a/arch/powerpc/platforms/pseries/vio.c
+++ b/arch/powerpc/platforms/pseries/vio.c
@@ -1289,7 +1289,7 @@ static void vio_bus_shutdown(struct device *dev)
                viodrv = to_vio_driver(dev->driver);
                if (viodrv->shutdown)
                        viodrv->shutdown(viodev);
-               else if (kexec_in_progress)
+               else if (kexec_in_progress())
                        vio_bus_remove(dev);
        }
 }
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 831613959a92..f91f35206489 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -122,21 +122,21 @@ void hv_remove_crash_handler(void)
 #ifdef CONFIG_KEXEC_CORE
 static void hv_machine_shutdown(void)
 {
-       if (kexec_in_progress && hv_kexec_handler)
+       if (kexec_in_progress() && hv_kexec_handler)
                hv_kexec_handler();
 
        /*
         * Call hv_cpu_die() on all the CPUs, otherwise later the hypervisor
         * corrupts the old VP Assist Pages and can crash the kexec kernel.
         */
-       if (kexec_in_progress && hyperv_init_cpuhp > 0)
+       if (kexec_in_progress() && hyperv_init_cpuhp > 0)
                cpuhp_remove_state(hyperv_init_cpuhp);
 
        /* The function calls stop_other_cpus(). */
        native_machine_shutdown();
 
        /* Disable the hypercall page when there is only 1 active CPU. */
-       if (kexec_in_progress)
+       if (kexec_in_progress())
                hyperv_cleanup();
 }
 
diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index c1cd28e915a3..769163833ffc 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -145,7 +145,7 @@ DEFINE_IDTENTRY_SYSVEC(sysvec_xen_hvm_callback)
 static void xen_hvm_shutdown(void)
 {
        native_machine_shutdown();
-       if (kexec_in_progress)
+       if (kexec_in_progress())
                xen_reboot(SHUTDOWN_soft_reset);
 }
 
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index a46df5d1d094..608bc2146802 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -1040,7 +1040,7 @@ static int update_efi_random_seed(struct notifier_block 
*nb,
        struct linux_efi_random_seed *seed;
        u32 size = 0;
 
-       if (!kexec_in_progress)
+       if (!kexec_in_progress())
                return NOTIFY_DONE;
 
        seed = memremap(efi_rng_seed, sizeof(*seed), MEMREMAP_WB);
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 107d77f3c846..23eeb7538b03 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -519,7 +519,7 @@ static void pci_device_shutdown(struct device *dev)
         * If it is not a kexec reboot, firmware will hit the PCI
         * devices with big hammer and stop their DMA any way.
         */
-       if (kexec_in_progress && (pci_dev->current_state <= PCI_D3hot))
+       if (kexec_in_progress() && pci_dev->current_state <= PCI_D3hot)
                pci_clear_master(pci_dev);
 }
 
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 41a686996aaa..2ec0aec1a0de 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -423,8 +423,7 @@ extern int kexec_load_disabled;
 #define KEXEC_FILE_FLAGS       (KEXEC_FILE_UNLOAD | KEXEC_FILE_ON_CRASH | \
                                 KEXEC_FILE_NO_INITRAMFS)
 
-/* flag to track if kexec reboot is in progress */
-extern bool kexec_in_progress;
+bool kexec_in_progress(void);
 
 int crash_shrink_memory(unsigned long new_size);
 ssize_t crash_get_memory_size(void);
@@ -507,7 +506,7 @@ static inline void __crash_kexec(struct pt_regs *regs) { }
 static inline void crash_kexec(struct pt_regs *regs) { }
 static inline int kexec_should_crash(struct task_struct *p) { return 0; }
 static inline int kexec_crash_loaded(void) { return 0; }
-#define kexec_in_progress false
+static inline bool kexec_in_progress(void) { return false; }
 #endif /* CONFIG_KEXEC_CORE */
 
 #ifdef CONFIG_KEXEC_SIG
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index ca2743f9c634..4495d0fc28ae 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -52,8 +52,16 @@ atomic_t __kexec_lock = ATOMIC_INIT(0);
 note_buf_t __percpu *crash_notes;
 
 /* Flag to indicate we are going to kexec a new kernel */
-bool kexec_in_progress = false;
+static bool kexec_in_progress_internal;
 
+/**
+ * kexec_in_progress - Check if the system is going to kexec
+ */
+bool kexec_in_progress(void)
+{
+       return kexec_in_progress_internal;
+}
+EXPORT_SYMBOL(kexec_in_progress);
 
 /* Location of the reserved area for the crash kernel */
 struct resource crashk_res = {
@@ -1175,7 +1183,7 @@ int kernel_kexec(void)
        } else
 #endif
        {
-               kexec_in_progress = true;
+               kexec_in_progress_internal = true;
                kernel_restart_prepare("kexec reboot");
                migrate_to_reboot_cpu();
 

-- 
2.39.0.rc0.267.gcb52ba06e7-goog-b4-0.11.0-dev-696ae