Jan Beulich
2009-Jun-03 16:05 UTC
[Xen-devel] [PATCH] linux: fix blkback/blktap2 interaction
blkback''s page map code needs to be accessible to both blkback and
blktap2, irrespective of whether either or both are modules. The
most immediate solution is to break it out into a separate, library-
like component that doesn''t need building if either of the two
consumers is configured off, and that gets built as a module if both
consumers are modules.
Also fix the dummy implementation of blkback_pagemap_read(), since
using BUG() there doesn''t compile.
This patch will only apply cleanly on top of the previously sent patch
allowing blktap2 to build as a module.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
--- head-2009-05-29.orig/drivers/xen/Kconfig 2009-06-03 16:12:43.000000000 +0200
+++ head-2009-05-29/drivers/xen/Kconfig 2009-06-03 10:26:22.000000000 +0200
@@ -76,6 +76,11 @@ config XEN_BLKDEV_TAP2
as files, in memory, or on other hosts across the network. This
driver can safely coexist with the existing blockback driver.
+config XEN_BLKBACK_PAGEMAP
+ tristate
+ depends on XEN_BLKDEV_BACKEND != n && XEN_BLKDEV_TAP2 != n
+ default XEN_BLKDEV_BACKEND || XEN_BLKDEV_TAP2
+
config XEN_NETDEV_BACKEND
tristate "Network-device backend driver"
depends on XEN_BACKEND && NET
--- head-2009-05-29.orig/drivers/xen/blkback/Makefile 2009-06-03
16:12:43.000000000 +0200
+++ head-2009-05-29/drivers/xen/blkback/Makefile 2009-06-03 09:50:42.000000000
+0200
@@ -1,3 +1,4 @@
obj-$(CONFIG_XEN_BLKDEV_BACKEND) := blkbk.o
+obj-$(CONFIG_XEN_BLKBACK_PAGEMAP) += blkback-pagemap.o
-blkbk-y := blkback.o xenbus.o interface.o vbd.o blkback-pagemap.o
+blkbk-y := blkback.o xenbus.o interface.o vbd.o
--- head-2009-05-29.orig/drivers/xen/blkback/blkback-pagemap.c 2009-06-03
16:12:43.000000000 +0200
+++ head-2009-05-29/drivers/xen/blkback/blkback-pagemap.c 2009-06-03
16:02:40.000000000 +0200
@@ -1,4 +1,4 @@
-#include "common.h"
+#include <linux/module.h>
#include "blkback-pagemap.h"
static int blkback_pagemap_size;
@@ -22,6 +22,7 @@ blkback_pagemap_init(int pages)
blkback_pagemap_size = pages;
return 0;
}
+EXPORT_SYMBOL_GPL(blkback_pagemap_init);
void
blkback_pagemap_set(int idx, struct page *page,
@@ -46,6 +47,7 @@ blkback_pagemap_set(int idx, struct page
entry->busid = busid;
entry->gref = gref;
}
+EXPORT_SYMBOL_GPL(blkback_pagemap_set);
void
blkback_pagemap_clear(struct page *page)
@@ -67,6 +69,7 @@ blkback_pagemap_clear(struct page *page)
memset(entry, 0, sizeof(*entry));
}
+EXPORT_SYMBOL_GPL(blkback_pagemap_clear);
struct blkback_pagemap
blkback_pagemap_read(struct page *page)
@@ -89,3 +92,5 @@ blkback_pagemap_read(struct page *page)
return *entry;
}
EXPORT_SYMBOL(blkback_pagemap_read);
+
+MODULE_LICENSE("Dual BSD/GPL");
--- head-2009-05-29.orig/drivers/xen/blkback/blkback-pagemap.h 2009-06-03
16:12:43.000000000 +0200
+++ head-2009-05-29/drivers/xen/blkback/blkback-pagemap.h 2009-06-03
16:13:17.000000000 +0200
@@ -1,6 +1,7 @@
#ifndef _BLKBACK_PAGEMAP_H_
#define _BLKBACK_PAGEMAP_H_
+#include <linux/mm.h>
#include <xen/interface/xen.h>
#include <xen/interface/grant_table.h>
@@ -12,6 +13,25 @@ struct blkback_pagemap {
grant_ref_t gref;
};
+#if defined(CONFIG_XEN_BLKBACK_PAGEMAP) ||
defined(CONFIG_XEN_BLKBACK_PAGEMAP_MODULE)
+
+int blkback_pagemap_init(int);
+void blkback_pagemap_set(int, struct page *, domid_t, busid_t, grant_ref_t);
+void blkback_pagemap_clear(struct page *);
struct blkback_pagemap blkback_pagemap_read(struct page *);
+#else /* CONFIG_XEN_BLKBACK_PAGEMAP */
+
+static inline int blkback_pagemap_init(int pages) { return 0; }
+static inline void blkback_pagemap_set(int idx, struct page *page, domid_t dom,
+ busid_t bus, grant_ref_t gnt) {}
+static inline void blkback_pagemap_clear(struct page *page) {}
+static inline struct blkback_pagemap blkback_pagemap_read(struct page *page)
+{
+ BUG();
+ return (struct blkback_pagemap){-1, -1, -1};
+}
+
+#endif /* CONFIG_XEN_BLKBACK_PAGEMAP */
+
#endif
--- head-2009-05-29.orig/drivers/xen/blkback/common.h 2009-06-03
16:12:43.000000000 +0200
+++ head-2009-05-29/drivers/xen/blkback/common.h 2009-06-03 09:55:06.000000000
+0200
@@ -150,8 +150,4 @@ int blkif_schedule(void *arg);
int blkback_barrier(struct xenbus_transaction xbt,
struct backend_info *be, int state);
-int blkback_pagemap_init(int);
-void blkback_pagemap_set(int, struct page *, domid_t, busid_t, grant_ref_t);
-void blkback_pagemap_clear(struct page *);
-
#endif /* __BLKIF__BACKEND__COMMON_H__ */
--- head-2009-05-29.orig/drivers/xen/blktap2/device.c 2009-06-03
16:12:43.000000000 +0200
+++ head-2009-05-29/drivers/xen/blktap2/device.c 2009-06-03 15:40:39.000000000
+0200
@@ -14,13 +14,7 @@
#include "blktap.h"
-#if defined(CONFIG_XEN_BLKDEV_BACKEND) || \
- (defined(CONFIG_XEN_BLKDEV_BACKEND_MODULE) && defined(MODULE))
#include "../blkback/blkback-pagemap.h"
-#else
-struct blkback_pagemap { };
-#define blkback_pagemap_read(page) BUG();
-#endif
#if 0
#define DPRINTK_IOCTL(_f, _a...) printk(KERN_ALERT _f, ## _a)
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