mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf.git
synced 2026-04-18 06:34:27 -04:00
53c0a58beb
The important part in sockfd_lookup_light() is avoiding needless file refcount operations, not the marginal reduction of the register pressure from not keeping a struct file pointer in the caller. Switch to use fdget()/fdpu(); with sane use of CLASS(fd) we can get a better code generation... Would be nice if somebody tested it on networking test suites (including benchmarks)... sockfd_lookup_light() does fdget(), uses sock_from_file() to get the associated socket and returns the struct socket reference to the caller, along with "do we need to fput()" flag. No matching fdput(), the caller does its equivalent manually, using the fact that sock->file points to the struct file the socket has come from. Get rid of that - have the callers do fdget()/fdput() and use sock_from_file() directly. That kills sockfd_lookup_light() and fput_light() (no users left). What's more, we can get rid of explicit fdget()/fdput() by switching to CLASS(fd, ...) - code generation does not suffer, since now fdput() inserted on "descriptor is not opened" failure exit is recognized to be a no-op by compiler. [folded a fix for braino in do_recvmmsg() caught by Simon Horman] Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
129 lines
3.5 KiB
C
129 lines
3.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Wrapper functions for accessing the file_struct fd array.
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*/
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#ifndef __LINUX_FILE_H
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#define __LINUX_FILE_H
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#include <linux/compiler.h>
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#include <linux/types.h>
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#include <linux/posix_types.h>
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#include <linux/errno.h>
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#include <linux/cleanup.h>
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#include <linux/err.h>
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struct file;
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extern void fput(struct file *);
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struct file_operations;
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struct task_struct;
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struct vfsmount;
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struct dentry;
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struct inode;
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struct path;
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extern struct file *alloc_file_pseudo(struct inode *, struct vfsmount *,
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const char *, int flags, const struct file_operations *);
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extern struct file *alloc_file_pseudo_noaccount(struct inode *, struct vfsmount *,
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const char *, int flags, const struct file_operations *);
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extern struct file *alloc_file_clone(struct file *, int flags,
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const struct file_operations *);
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/* either a reference to struct file + flags
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* (cloned vs. borrowed, pos locked), with
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* flags stored in lower bits of value,
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* or empty (represented by 0).
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*/
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struct fd {
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unsigned long word;
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};
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#define FDPUT_FPUT 1
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#define FDPUT_POS_UNLOCK 2
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#define fd_file(f) ((struct file *)((f).word & ~(FDPUT_FPUT|FDPUT_POS_UNLOCK)))
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static inline bool fd_empty(struct fd f)
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{
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return unlikely(!f.word);
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}
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#define EMPTY_FD (struct fd){0}
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static inline struct fd BORROWED_FD(struct file *f)
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{
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return (struct fd){(unsigned long)f};
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}
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static inline struct fd CLONED_FD(struct file *f)
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{
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return (struct fd){(unsigned long)f | FDPUT_FPUT};
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}
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static inline void fdput(struct fd fd)
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{
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if (fd.word & FDPUT_FPUT)
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fput(fd_file(fd));
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}
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extern struct file *fget(unsigned int fd);
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extern struct file *fget_raw(unsigned int fd);
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extern struct file *fget_task(struct task_struct *task, unsigned int fd);
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extern void __f_unlock_pos(struct file *);
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struct fd fdget(unsigned int fd);
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struct fd fdget_raw(unsigned int fd);
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struct fd fdget_pos(unsigned int fd);
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static inline void fdput_pos(struct fd f)
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{
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if (f.word & FDPUT_POS_UNLOCK)
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__f_unlock_pos(fd_file(f));
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fdput(f);
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}
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DEFINE_CLASS(fd, struct fd, fdput(_T), fdget(fd), int fd)
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DEFINE_CLASS(fd_raw, struct fd, fdput(_T), fdget_raw(fd), int fd)
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extern int f_dupfd(unsigned int from, struct file *file, unsigned flags);
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extern int replace_fd(unsigned fd, struct file *file, unsigned flags);
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extern void set_close_on_exec(unsigned int fd, int flag);
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extern bool get_close_on_exec(unsigned int fd);
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extern int __get_unused_fd_flags(unsigned flags, unsigned long nofile);
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extern int get_unused_fd_flags(unsigned flags);
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extern void put_unused_fd(unsigned int fd);
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DEFINE_CLASS(get_unused_fd, int, if (_T >= 0) put_unused_fd(_T),
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get_unused_fd_flags(flags), unsigned flags)
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DEFINE_FREE(fput, struct file *, if (!IS_ERR_OR_NULL(_T)) fput(_T))
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/*
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* take_fd() will take care to set @fd to -EBADF ensuring that
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* CLASS(get_unused_fd) won't call put_unused_fd(). This makes it
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* easier to rely on CLASS(get_unused_fd):
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*
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* struct file *f;
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*
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* CLASS(get_unused_fd, fd)(O_CLOEXEC);
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* if (fd < 0)
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* return fd;
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*
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* f = dentry_open(&path, O_RDONLY, current_cred());
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* if (IS_ERR(f))
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* return PTR_ERR(f);
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*
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* fd_install(fd, f);
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* return take_fd(fd);
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*/
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#define take_fd(fd) __get_and_null(fd, -EBADF)
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extern void fd_install(unsigned int fd, struct file *file);
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int receive_fd(struct file *file, int __user *ufd, unsigned int o_flags);
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int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags);
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extern void flush_delayed_fput(void);
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extern void __fput_sync(struct file *);
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extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max;
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#endif /* __LINUX_FILE_H */
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