[PATCH 3/4] PCI: Provide lock guard for pci_rescan_remove_lock

[Benjamin Block]

Make it possible to use guard() or scoped_guard() to lock, and
automatically unlock `pci_rescan_remove_lock`.

Since the actual mutex `pci_rescan_remove_lock` is always supposed to be
taken and released using the functions pci_lock_rescan_remove() and
pci_unlock_rescan_remove() it is not possible to simply use the already
existing guards for `struct mutex`. Instead define a new guard
`pci_rescan_remove` that will also call the functions in question, but
is usable as via guard() or scoped_guard().

Signed-off-by: Benjamin Block <bblock@xxxxxxxxxxxxx>
---
 include/linux/pci.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/linux/pci.h b/include/linux/pci.h
index fd7a962a64ef..4c41b5a2c90a 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -41,6 +41,7 @@
 #include <linux/msi_api.h>
 #include <linux/mutex.h>
 #include <uapi/linux/pci.h>
+#include <linux/cleanup.h>
 
 #include <linux/pci_ids.h>
 
@@ -1537,6 +1538,8 @@ unsigned int pci_rescan_bus(struct pci_bus *bus);
 extern struct mutex pci_rescan_remove_lock;
 void pci_lock_rescan_remove(void);
 void pci_unlock_rescan_remove(void);
+DEFINE_LOCK_GUARD_0(pci_rescan_remove, pci_lock_rescan_remove(),
+		    pci_unlock_rescan_remove());
 
 /* Vital Product Data routines */
 ssize_t pci_read_vpd(struct pci_dev *dev, loff_t pos, size_t count, void *buf);
-- 
2.53.0