FreeBSD/Linux Kernel Cross Reference
sys/compat/linuxkpi/common/include/linux/file.h

     /*-
      * Copyright (c) 2010 Isilon Systems, Inc.
      * Copyright (c) 2010 iX Systems, Inc.
      * Copyright (c) 2010 Panasas, Inc.
      * Copyright (c) 2013-2017 Mellanox Technologies, Ltd.
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice unmodified, this list of conditions, and the following
     *    disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     *
     * $FreeBSD$
     */
    #ifndef _LINUXKPI_LINUX_FILE_H_
    #define _LINUXKPI_LINUX_FILE_H_
    
    #include <sys/param.h>
    #include <sys/file.h>
    #include <sys/filedesc.h>
    #include <sys/refcount.h>
    #include <sys/capsicum.h>
    #include <sys/proc.h>
    
    #include <linux/fs.h>
    #include <linux/slab.h>
    
    struct linux_file;
    
    #undef file
    
    extern struct fileops linuxfileops;
    
    static inline struct linux_file *
    linux_fget(unsigned int fd)
    {
            struct file *file;
    
            /* lookup file pointer by file descriptor index */
            if (fget_unlocked(curthread, fd, &cap_no_rights, &file) != 0)
                    return (NULL);
    
            /* check if file handle really belongs to us */
            if (file->f_data == NULL ||
                file->f_ops != &linuxfileops) {
                    fdrop(file, curthread);
                    return (NULL);
            }
            return ((struct linux_file *)file->f_data);
    }
    
    extern void linux_file_free(struct linux_file *filp);
    
    static inline void
    fput(struct linux_file *filp)
    {
            if (refcount_release(filp->_file == NULL ?
                &filp->f_count : &filp->_file->f_count)) {
                    linux_file_free(filp);
            }
    }
    
    static inline unsigned int
    file_count(struct linux_file *filp)
    {
            return (filp->_file == NULL ?
                filp->f_count : filp->_file->f_count);
    }
    
    static inline void
    put_unused_fd(unsigned int fd)
    {
            struct file *file;
    
            if (fget_unlocked(curthread, fd, &cap_no_rights, &file) != 0) {
                    return;
            }
            /*
             * NOTE: We should only get here when the "fd" has not been
             * installed, so no need to free the associated Linux file
             * structure.
             */
            fdclose(curthread, file, fd);
   
           /* drop extra reference */
           fdrop(file, curthread);
   }
   
   static inline void
   fd_install(unsigned int fd, struct linux_file *filp)
   {
           struct file *file;
   
           if (fget_unlocked(curthread, fd, &cap_no_rights, &file) != 0) {
                   filp->_file = NULL;
           } else {
                   filp->_file = file;
                   finit(file, filp->f_mode, DTYPE_DEV, filp, &linuxfileops);
   
                   /* transfer reference count from "filp" to "file" */
                   while (refcount_release(&filp->f_count) == 0)
                           refcount_acquire(&file->f_count);
           }
   
           /* drop the extra reference */
           fput(filp);
   }
   
   static inline int
   get_unused_fd(void)
   {
           struct file *file;
           int error;
           int fd;
   
           error = falloc(curthread, &file, &fd, 0);
           if (error)
                   return -error;
           /* drop the extra reference */
           fdrop(file, curthread);
           return fd;
   }
   
   static inline int
   get_unused_fd_flags(int flags)
   {
           struct file *file;
           int error;
           int fd;
   
           error = falloc(curthread, &file, &fd, flags);
           if (error)
                   return -error;
           /* drop the extra reference */
           fdrop(file, curthread);
           return fd;
   }
   
   extern struct linux_file *linux_file_alloc(void);
   
   static inline struct linux_file *
   alloc_file(int mode, const struct file_operations *fops)
   {
           struct linux_file *filp;
   
           filp = linux_file_alloc();
           filp->f_op = fops;
           filp->f_mode = mode;
   
           return (filp);
   }
   
   struct fd {
           struct linux_file *linux_file;
   };
   
   static inline void fdput(struct fd fd)
   {
           fput(fd.linux_file);
   }
   
   static inline struct fd fdget(unsigned int fd)
   {
           struct linux_file *f = linux_fget(fd);
           return (struct fd){f};
   }
   
   #define file            linux_file
   #define fget(...)       linux_fget(__VA_ARGS__)
   
   #endif  /* _LINUXKPI_LINUX_FILE_H_ */

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