s390/pci: add locking for fmb access
Function measurement can be toggled at runtime. Make sure that
all access to the fmb is protected via a mutex.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index 2818938..598f023 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -827,6 +827,7 @@
if (rc)
goto out;
+ mutex_init(&zdev->lock);
if (zdev->state == ZPCI_FN_STATE_CONFIGURED) {
rc = zpci_enable_device(zdev);
if (rc)
diff --git a/arch/s390/pci/pci_debug.c b/arch/s390/pci/pci_debug.c
index 97db1a4..3fc9b4d 100644
--- a/arch/s390/pci/pci_debug.c
+++ b/arch/s390/pci/pci_debug.c
@@ -58,8 +58,12 @@
if (!zdev)
return 0;
- if (!zdev->fmb)
+
+ mutex_lock(&zdev->lock);
+ if (!zdev->fmb) {
+ mutex_unlock(&zdev->lock);
return seq_printf(m, "FMB statistics disabled\n");
+ }
/* header */
seq_printf(m, "FMB @ %p\n", zdev->fmb);
@@ -78,6 +82,7 @@
pci_perf_names[i], *(stat + i));
pci_sw_counter_show(m);
+ mutex_unlock(&zdev->lock);
return 0;
}
@@ -95,19 +100,17 @@
if (rc)
return rc;
+ mutex_lock(&zdev->lock);
switch (val) {
case 0:
rc = zpci_fmb_disable_device(zdev);
- if (rc)
- return rc;
break;
case 1:
rc = zpci_fmb_enable_device(zdev);
- if (rc)
- return rc;
break;
}
- return count;
+ mutex_unlock(&zdev->lock);
+ return rc ? rc : count;
}
static int pci_perf_seq_open(struct inode *inode, struct file *filp)