Fix: do not use bdi_unknown_name symbol

Use the GPL-exported bdi_dev_name introduced in kernel 5.7. Do not use
static inline bdi_dev_name in prior kernels because it uses the bdi_unknown_name
symbol which is not exported to GPL modules.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I8b4e4fd84ecacef7942b308e615ca88db8dce7b6

diff --git a/include/instrumentation/events/writeback.h b/include/instrumentation/events/writeback.h
index f24237b296f507283c1a3c46bcfbf372764c64fe..f05708a8376c6f949665eae06b19c4087977cf75 100644 (file)
--- a/include/instrumentation/events/writeback.h
+++ b/include/instrumentation/events/writeback.h
@@ -14,9 +14,12 @@
 #ifndef _TRACE_WRITEBACK_DEF_
 #define _TRACE_WRITEBACK_DEF_
 
-#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,6,0) ||        \
-       LTTNG_KERNEL_RANGE(5,5,3, 5,6,0) ||                     \
-       LTTNG_KERNEL_RANGE(5,4,19, 5,5,0))
+/*
+ * Use the GPL-exported bdi_dev_name introduced in kernel 5.7. Do not use
+ * static inline bdi_dev_name in prior kernels because it uses the bdi_unknown_name
+ * symbol which is not exported to GPL modules.
+ */
+#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,7,0))
 static inline const char *lttng_bdi_dev_name(struct backing_dev_info *bdi)
 {
        return bdi_dev_name(bdi);