From: Michael Jeanson <mjeanson@efficios.com>
Date: Thu, 2 Jul 2020 16:06:42 +0000 (-0400)
Subject: Use exported symbol bdevname() instead of disk_name()
X-Git-Tag: v2.11.5~13
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=bf5a011d7256c26f8731be6b9983462f02b7c0cb;p=lttng-modules.git

Use exported symbol bdevname() instead of disk_name()

bdevname() is a simple wrapper over disk_name() but has the honor to be
exported. Using it removes the need for a kallsym wrapper.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ic2b2233c4db7826175c68edea69751ddcb17a5e6
---

diff --git a/lttng-statedump-impl.c b/lttng-statedump-impl.c
index 5225186b..54a309d1 100644
--- a/lttng-statedump-impl.c
+++ b/lttng-statedump-impl.c
@@ -138,10 +138,19 @@ int lttng_enumerate_block_devices(struct lttng_session *session)
 
 		disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
 		while ((part = disk_part_iter_next(&piter))) {
+			struct block_device bdev;
 			char name_buf[BDEVNAME_SIZE];
-			char *p;
+			const char *p;
 
-			p = wrapper_disk_name(disk, part->partno, name_buf);
+			/*
+			 * Create a partial 'struct blockdevice' to use
+			 * 'bdevname()' which is a simple wrapper over
+			 * 'disk_name()' but has the honor to be EXPORT_SYMBOL.
+			 */
+			bdev.bd_disk = disk;
+			bdev.bd_part = part;
+
+			p = bdevname(&bdev, name_buf);
 			if (!p) {
 				disk_part_iter_exit(&piter);
 				class_dev_iter_exit(&iter);
diff --git a/wrapper/genhd.h b/wrapper/genhd.h
index a44198a7..4eac2c1a 100644
--- a/wrapper/genhd.h
+++ b/wrapper/genhd.h
@@ -14,37 +14,11 @@
 
 #include <linux/genhd.h>
 
-#ifdef CONFIG_KALLSYMS
+#ifdef CONFIG_KALLSYMS_ALL
 
 #include <linux/kallsyms.h>
 #include <wrapper/kallsyms.h>
 
-static inline
-char *wrapper_disk_name(struct gendisk *hd, int partno, char *buf)
-{
-	char *(*disk_name_sym)(struct gendisk *hd, int partno, char *buf);
-
-	disk_name_sym = (void *) kallsyms_lookup_funcptr("disk_name");
-	if (disk_name_sym) {
-		return disk_name_sym(hd, partno, buf);
-	} else {
-		printk_once(KERN_WARNING "LTTng: disk_name symbol lookup failed.\n");
-		return NULL;
-	}
-}
-
-#else
-
-static inline
-char *wrapper_disk_name(struct gendisk *hd, int partno, char *buf)
-{
-	return disk_name(hd, partno, buf);
-}
-
-#endif
-
-#ifdef CONFIG_KALLSYMS_ALL
-
 static inline
 struct class *wrapper_get_block_class(void)
 {