libfs: allow error return from simple attributes

Sometimes simple attributes might need to return an error, e.g. for
acquiring a mutex interruptibly.  In fact we have that situation in
spufs already which is the original user of the simple attributes.  This
patch merged the temporarily forked attributes in spufs back into the
main ones and allows to return errors.

[akpm@linux-foundation.org: build fix]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: <stefano.brivio@polimi.it>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg KH <greg@kroah.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 20 insertions, 12 deletions

diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index fa6b7f7ff914..fddffe4851f5 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -56,13 +56,15 @@ const struct inode_operations debugfs_link_operations = {
 	.follow_link    = debugfs_follow_link,
 };
 
-static void debugfs_u8_set(void *data, u64 val)
+static int debugfs_u8_set(void *data, u64 val)
 {
 	*(u8 *)data = val;
+	return 0;
 }
-static u64 debugfs_u8_get(void *data)
+static int debugfs_u8_get(void *data, u64 *val)
 {
-	return *(u8 *)data;
+	*val = *(u8 *)data;
+	return 0;
 }
 DEFINE_SIMPLE_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
 
@@ -97,13 +99,15 @@ struct dentry *debugfs_create_u8(const char *name, mode_t mode,
 }
 EXPORT_SYMBOL_GPL(debugfs_create_u8);
 
-static void debugfs_u16_set(void *data, u64 val)
+static int debugfs_u16_set(void *data, u64 val)
 {
 	*(u16 *)data = val;
+	return 0;
 }
-static u64 debugfs_u16_get(void *data)
+static int debugfs_u16_get(void *data, u64 *val)
 {
-	return *(u16 *)data;
+	*val = *(u16 *)data;
+	return 0;
 }
 DEFINE_SIMPLE_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
 
@@ -138,13 +142,15 @@ struct dentry *debugfs_create_u16(const char *name, mode_t mode,
 }
 EXPORT_SYMBOL_GPL(debugfs_create_u16);
 
-static void debugfs_u32_set(void *data, u64 val)
+static int debugfs_u32_set(void *data, u64 val)
 {
 	*(u32 *)data = val;
+	return 0;
 }
-static u64 debugfs_u32_get(void *data)
+static int debugfs_u32_get(void *data, u64 *val)
 {
-	return *(u32 *)data;
+	*val = *(u32 *)data;
+	return 0;
 }
 DEFINE_SIMPLE_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
 
@@ -179,14 +185,16 @@ struct dentry *debugfs_create_u32(const char *name, mode_t mode,
 }
 EXPORT_SYMBOL_GPL(debugfs_create_u32);
 
-static void debugfs_u64_set(void *data, u64 val)
+static int debugfs_u64_set(void *data, u64 val)
 {
 	*(u64 *)data = val;
+	return 0;
 }
 
-static u64 debugfs_u64_get(void *data)
+static int debugfs_u64_get(void *data, u64 *val)
 {
-	return *(u64 *)data;
+	*val = *(u64 *)data;
+	return 0;
 }
 DEFINE_SIMPLE_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");