netfs: Further cleanups after struct netfs_inode wrapper introduced

Change the signature of netfs helper functions to take a struct netfs_inode
pointer rather than a struct inode pointer where appropriate, thereby
relieving the need for the network filesystem to convert its internal inode
format down to the VFS inode only for netfslib to bounce it back up.  For
type safety, it's better not to do that (and it's less typing too).

Give netfs_write_begin() an extra argument to pass in a pointer to the
netfs_inode struct rather than deriving it internally from the file
pointer.  Note that the ->write_begin() and ->write_end() ops are intended
to be replaced in the future by netfslib code that manages this without the
need to call in twice for each page.

netfs_readpage() and similar are intended to be pointed at directly by the
address_space_operations table, so must stick to the signature dictated by
the function pointers there.

Changes
=======
- Updated the kerneldoc comments and documentation [DH].

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/CAHk-=wgkwKyNmNdKpQkqZ6DnmUL-x9hp0YBnUGjaPFEAdxDTbw@mail.gmail.com/

1 files changed, 9 insertions, 13 deletions

diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index 6dbb4c9ce50d..a62739f3726b 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -277,7 +277,8 @@ struct netfs_cache_ops {
 struct readahead_control;
 extern void netfs_readahead(struct readahead_control *);
 int netfs_read_folio(struct file *, struct folio *);
-extern int netfs_write_begin(struct file *, struct address_space *,
+extern int netfs_write_begin(struct netfs_inode *,
+			     struct file *, struct address_space *,
 			     loff_t, unsigned int, struct folio **,
 			     void **);
 
@@ -302,19 +303,17 @@ static inline struct netfs_inode *netfs_inode(struct inode *inode)
 
 /**
  * netfs_inode_init - Initialise a netfslib inode context
- * @inode: The inode with which the context is associated
+ * @inode: The netfs inode to initialise
  * @ops: The netfs's operations list
  *
  * Initialise the netfs library context struct.  This is expected to follow on
  * directly from the VFS inode struct.
  */
-static inline void netfs_inode_init(struct inode *inode,
+static inline void netfs_inode_init(struct netfs_inode *ctx,
 				    const struct netfs_request_ops *ops)
 {
-	struct netfs_inode *ctx = netfs_inode(inode);
-
 	ctx->ops = ops;
-	ctx->remote_i_size = i_size_read(inode);
+	ctx->remote_i_size = i_size_read(&ctx->inode);
 #if IS_ENABLED(CONFIG_FSCACHE)
 	ctx->cache = NULL;
 #endif
@@ -322,28 +321,25 @@ static inline void netfs_inode_init(struct inode *inode,
 
 /**
  * netfs_resize_file - Note that a file got resized
- * @inode: The inode being resized
+ * @ctx: The netfs inode being resized
  * @new_i_size: The new file size
  *
  * Inform the netfs lib that a file got resized so that it can adjust its state.
  */
-static inline void netfs_resize_file(struct inode *inode, loff_t new_i_size)
+static inline void netfs_resize_file(struct netfs_inode *ctx, loff_t new_i_size)
 {
-	struct netfs_inode *ctx = netfs_inode(inode);
-
 	ctx->remote_i_size = new_i_size;
 }
 
 /**
  * netfs_i_cookie - Get the cache cookie from the inode
- * @inode: The inode to query
+ * @ctx: The netfs inode to query
  *
  * Get the caching cookie (if enabled) from the network filesystem's inode.
  */
-static inline struct fscache_cookie *netfs_i_cookie(struct inode *inode)
+static inline struct fscache_cookie *netfs_i_cookie(struct netfs_inode *ctx)
 {
 #if IS_ENABLED(CONFIG_FSCACHE)
-	struct netfs_inode *ctx = netfs_inode(inode);
 	return ctx->cache;
 #else
 	return NULL;