Revision 8c89ecf5c13b0504018c5045896a0b78d5d811e6 authored by Alexander Potapenko on 11 January 2023, 10:50:12 UTC, committed by Alexander Potapenko on 07 February 2023, 09:50:25 UTC
When building the kernel with W=1, the compiler reports numerous warnings about the missing prototypes for KMSAN instrumentation hooks. Because these functions are not supposed to be called explicitly by the kernel code (calls to them are emitted by the compiler), they do not have to be declared in the headers. Instead, we add forward declarations right before the definitions to silence the warnings produced by -Wmissing-prototypes. Reported-by: kernel test robot <lkp@intel.com> Link: https://lore.kernel.org/lkml/202301020356.dFruA4I5-lkp@intel.com/T/ Reported-by: Vlastimil Babka <vbabka@suse.cz> Suggested-by: Marco Elver <elver@google.com> Signed-off-by: Alexander Potapenko <glider@google.com>
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netfs.h
/* SPDX-License-Identifier: GPL-2.0-or-later */
/* Network filesystem support services.
*
* Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* See:
*
* Documentation/filesystems/netfs_library.rst
*
* for a description of the network filesystem interface declared here.
*/
#ifndef _LINUX_NETFS_H
#define _LINUX_NETFS_H
#include <linux/workqueue.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
enum netfs_sreq_ref_trace;
/*
* Overload PG_private_2 to give us PG_fscache - this is used to indicate that
* a page is currently backed by a local disk cache
*/
#define folio_test_fscache(folio) folio_test_private_2(folio)
#define PageFsCache(page) PagePrivate2((page))
#define SetPageFsCache(page) SetPagePrivate2((page))
#define ClearPageFsCache(page) ClearPagePrivate2((page))
#define TestSetPageFsCache(page) TestSetPagePrivate2((page))
#define TestClearPageFsCache(page) TestClearPagePrivate2((page))
/**
* folio_start_fscache - Start an fscache write on a folio.
* @folio: The folio.
*
* Call this function before writing a folio to a local cache. Starting a
* second write before the first one finishes is not allowed.
*/
static inline void folio_start_fscache(struct folio *folio)
{
VM_BUG_ON_FOLIO(folio_test_private_2(folio), folio);
folio_get(folio);
folio_set_private_2(folio);
}
/**
* folio_end_fscache - End an fscache write on a folio.
* @folio: The folio.
*
* Call this function after the folio has been written to the local cache.
* This will wake any sleepers waiting on this folio.
*/
static inline void folio_end_fscache(struct folio *folio)
{
folio_end_private_2(folio);
}
/**
* folio_wait_fscache - Wait for an fscache write on this folio to end.
* @folio: The folio.
*
* If this folio is currently being written to a local cache, wait for
* the write to finish. Another write may start after this one finishes,
* unless the caller holds the folio lock.
*/
static inline void folio_wait_fscache(struct folio *folio)
{
folio_wait_private_2(folio);
}
/**
* folio_wait_fscache_killable - Wait for an fscache write on this folio to end.
* @folio: The folio.
*
* If this folio is currently being written to a local cache, wait
* for the write to finish or for a fatal signal to be received.
* Another write may start after this one finishes, unless the caller
* holds the folio lock.
*
* Return:
* - 0 if successful.
* - -EINTR if a fatal signal was encountered.
*/
static inline int folio_wait_fscache_killable(struct folio *folio)
{
return folio_wait_private_2_killable(folio);
}
static inline void set_page_fscache(struct page *page)
{
folio_start_fscache(page_folio(page));
}
static inline void end_page_fscache(struct page *page)
{
folio_end_private_2(page_folio(page));
}
static inline void wait_on_page_fscache(struct page *page)
{
folio_wait_private_2(page_folio(page));
}
static inline int wait_on_page_fscache_killable(struct page *page)
{
return folio_wait_private_2_killable(page_folio(page));
}
enum netfs_io_source {
NETFS_FILL_WITH_ZEROES,
NETFS_DOWNLOAD_FROM_SERVER,
NETFS_READ_FROM_CACHE,
NETFS_INVALID_READ,
} __mode(byte);
typedef void (*netfs_io_terminated_t)(void *priv, ssize_t transferred_or_error,
bool was_async);
/*
* Per-inode context. This wraps the VFS inode.
*/
struct netfs_inode {
struct inode inode; /* The VFS inode */
const struct netfs_request_ops *ops;
#if IS_ENABLED(CONFIG_FSCACHE)
struct fscache_cookie *cache;
#endif
loff_t remote_i_size; /* Size of the remote file */
};
/*
* Resources required to do operations on a cache.
*/
struct netfs_cache_resources {
const struct netfs_cache_ops *ops;
void *cache_priv;
void *cache_priv2;
unsigned int debug_id; /* Cookie debug ID */
unsigned int inval_counter; /* object->inval_counter at begin_op */
};
/*
* Descriptor for a single component subrequest.
*/
struct netfs_io_subrequest {
struct netfs_io_request *rreq; /* Supervising I/O request */
struct list_head rreq_link; /* Link in rreq->subrequests */
loff_t start; /* Where to start the I/O */
size_t len; /* Size of the I/O */
size_t transferred; /* Amount of data transferred */
refcount_t ref;
short error; /* 0 or error that occurred */
unsigned short debug_index; /* Index in list (for debugging output) */
enum netfs_io_source source; /* Where to read from/write to */
unsigned long flags;
#define NETFS_SREQ_COPY_TO_CACHE 0 /* Set if should copy the data to the cache */
#define NETFS_SREQ_CLEAR_TAIL 1 /* Set if the rest of the read should be cleared */
#define NETFS_SREQ_SHORT_IO 2 /* Set if the I/O was short */
#define NETFS_SREQ_SEEK_DATA_READ 3 /* Set if ->read() should SEEK_DATA first */
#define NETFS_SREQ_NO_PROGRESS 4 /* Set if we didn't manage to read any data */
#define NETFS_SREQ_ONDEMAND 5 /* Set if it's from on-demand read mode */
};
enum netfs_io_origin {
NETFS_READAHEAD, /* This read was triggered by readahead */
NETFS_READPAGE, /* This read is a synchronous read */
NETFS_READ_FOR_WRITE, /* This read is to prepare a write */
} __mode(byte);
/*
* Descriptor for an I/O helper request. This is used to make multiple I/O
* operations to a variety of data stores and then stitch the result together.
*/
struct netfs_io_request {
struct work_struct work;
struct inode *inode; /* The file being accessed */
struct address_space *mapping; /* The mapping being accessed */
struct netfs_cache_resources cache_resources;
struct list_head subrequests; /* Contributory I/O operations */
void *netfs_priv; /* Private data for the netfs */
unsigned int debug_id;
atomic_t nr_outstanding; /* Number of ops in progress */
atomic_t nr_copy_ops; /* Number of copy-to-cache ops in progress */
size_t submitted; /* Amount submitted for I/O so far */
size_t len; /* Length of the request */
short error; /* 0 or error that occurred */
enum netfs_io_origin origin; /* Origin of the request */
loff_t i_size; /* Size of the file */
loff_t start; /* Start position */
pgoff_t no_unlock_folio; /* Don't unlock this folio after read */
refcount_t ref;
unsigned long flags;
#define NETFS_RREQ_INCOMPLETE_IO 0 /* Some ioreqs terminated short or with error */
#define NETFS_RREQ_COPY_TO_CACHE 1 /* Need to write to the cache */
#define NETFS_RREQ_NO_UNLOCK_FOLIO 2 /* Don't unlock no_unlock_folio on completion */
#define NETFS_RREQ_DONT_UNLOCK_FOLIOS 3 /* Don't unlock the folios on completion */
#define NETFS_RREQ_FAILED 4 /* The request failed */
#define NETFS_RREQ_IN_PROGRESS 5 /* Unlocked when the request completes */
const struct netfs_request_ops *netfs_ops;
};
/*
* Operations the network filesystem can/must provide to the helpers.
*/
struct netfs_request_ops {
int (*init_request)(struct netfs_io_request *rreq, struct file *file);
void (*free_request)(struct netfs_io_request *rreq);
int (*begin_cache_operation)(struct netfs_io_request *rreq);
void (*expand_readahead)(struct netfs_io_request *rreq);
bool (*clamp_length)(struct netfs_io_subrequest *subreq);
void (*issue_read)(struct netfs_io_subrequest *subreq);
bool (*is_still_valid)(struct netfs_io_request *rreq);
int (*check_write_begin)(struct file *file, loff_t pos, unsigned len,
struct folio **foliop, void **_fsdata);
void (*done)(struct netfs_io_request *rreq);
};
/*
* How to handle reading from a hole.
*/
enum netfs_read_from_hole {
NETFS_READ_HOLE_IGNORE,
NETFS_READ_HOLE_CLEAR,
NETFS_READ_HOLE_FAIL,
};
/*
* Table of operations for access to a cache. This is obtained by
* rreq->ops->begin_cache_operation().
*/
struct netfs_cache_ops {
/* End an operation */
void (*end_operation)(struct netfs_cache_resources *cres);
/* Read data from the cache */
int (*read)(struct netfs_cache_resources *cres,
loff_t start_pos,
struct iov_iter *iter,
enum netfs_read_from_hole read_hole,
netfs_io_terminated_t term_func,
void *term_func_priv);
/* Write data to the cache */
int (*write)(struct netfs_cache_resources *cres,
loff_t start_pos,
struct iov_iter *iter,
netfs_io_terminated_t term_func,
void *term_func_priv);
/* Expand readahead request */
void (*expand_readahead)(struct netfs_cache_resources *cres,
loff_t *_start, size_t *_len, loff_t i_size);
/* Prepare a read operation, shortening it to a cached/uncached
* boundary as appropriate.
*/
enum netfs_io_source (*prepare_read)(struct netfs_io_subrequest *subreq,
loff_t i_size);
/* Prepare a write operation, working out what part of the write we can
* actually do.
*/
int (*prepare_write)(struct netfs_cache_resources *cres,
loff_t *_start, size_t *_len, loff_t i_size,
bool no_space_allocated_yet);
/* Prepare an on-demand read operation, shortening it to a cached/uncached
* boundary as appropriate.
*/
enum netfs_io_source (*prepare_ondemand_read)(struct netfs_cache_resources *cres,
loff_t start, size_t *_len,
loff_t i_size,
unsigned long *_flags, ino_t ino);
/* Query the occupancy of the cache in a region, returning where the
* next chunk of data starts and how long it is.
*/
int (*query_occupancy)(struct netfs_cache_resources *cres,
loff_t start, size_t len, size_t granularity,
loff_t *_data_start, size_t *_data_len);
};
struct readahead_control;
void netfs_readahead(struct readahead_control *);
int netfs_read_folio(struct file *, struct folio *);
int netfs_write_begin(struct netfs_inode *, struct file *,
struct address_space *, loff_t pos, unsigned int len,
struct folio **, void **fsdata);
void netfs_subreq_terminated(struct netfs_io_subrequest *, ssize_t, bool);
void netfs_get_subrequest(struct netfs_io_subrequest *subreq,
enum netfs_sreq_ref_trace what);
void netfs_put_subrequest(struct netfs_io_subrequest *subreq,
bool was_async, enum netfs_sreq_ref_trace what);
void netfs_stats_show(struct seq_file *);
/**
* netfs_inode - Get the netfs inode context from the inode
* @inode: The inode to query
*
* Get the netfs lib inode context from the network filesystem's inode. The
* context struct is expected to directly follow on from the VFS inode struct.
*/
static inline struct netfs_inode *netfs_inode(struct inode *inode)
{
return container_of(inode, struct netfs_inode, inode);
}
/**
* netfs_inode_init - Initialise a netfslib inode context
* @ctx: 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 netfs_inode *ctx,
const struct netfs_request_ops *ops)
{
ctx->ops = ops;
ctx->remote_i_size = i_size_read(&ctx->inode);
#if IS_ENABLED(CONFIG_FSCACHE)
ctx->cache = NULL;
#endif
}
/**
* netfs_resize_file - Note that a file got 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 netfs_inode *ctx, loff_t new_i_size)
{
ctx->remote_i_size = new_i_size;
}
/**
* netfs_i_cookie - Get the cache cookie from the inode
* @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 netfs_inode *ctx)
{
#if IS_ENABLED(CONFIG_FSCACHE)
return ctx->cache;
#else
return NULL;
#endif
}
#endif /* _LINUX_NETFS_H */
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