mm/prfile.c

   1 /*
   2  * SPDX-License-Identifier: GPL-2.0
   3  * Mainly for aufs which mmap(2) different file and wants to print different
   4  * path in /proc/PID/maps.
   5  * Call these functions via macros defined in linux/mm.h.
   6  *
   7  * See Documentation/filesystems/aufs/design/06mmap.txt
   8  *
   9  * Copyright (c) 2014-2017 Junjro R. Okajima
  10  * Copyright (c) 2014 Ian Campbell
  11  */
  12
  13 #include <linux/mm.h>
  14 #include <linux/file.h>
  15 #include <linux/fs.h>
  16
  17 /* #define PRFILE_TRACE */
  18 static inline void prfile_trace(struct file *f, struct file *pr,
  19                               const char func[], int line, const char func2[])
  20 {
  21 #ifdef PRFILE_TRACE
  22         if (pr)
  23                 pr_info("%s:%d: %s, %pD2\n", func, line, func2, f);
  24 #endif
  25 }
  26
  27 void vma_do_file_update_time(struct vm_area_struct *vma, const char func[],
  28                              int line)
  29 {
  30         struct file *f = vma->vm_file, *pr = vma->vm_prfile;
  31
  32         prfile_trace(f, pr, func, line, __func__);
  33         file_update_time(f);
  34         if (f && pr)
  35                 file_update_time(pr);
  36 }
  37
  38 struct file *vma_do_pr_or_file(struct vm_area_struct *vma, const char func[],
  39                                int line)
  40 {
  41         struct file *f = vma->vm_file, *pr = vma->vm_prfile;
  42
  43         prfile_trace(f, pr, func, line, __func__);
  44         return (f && pr) ? pr : f;
  45 }
  46
  47 void vma_do_get_file(struct vm_area_struct *vma, const char func[], int line)
  48 {
  49         struct file *f = vma->vm_file, *pr = vma->vm_prfile;
  50
  51         prfile_trace(f, pr, func, line, __func__);
  52         get_file(f);
  53         if (f && pr)
  54                 get_file(pr);
  55 }
  56
  57 void vma_do_fput(struct vm_area_struct *vma, const char func[], int line)
  58 {
  59         struct file *f = vma->vm_file, *pr = vma->vm_prfile;
  60
  61         prfile_trace(f, pr, func, line, __func__);
  62         fput(f);
  63         if (f && pr)
  64                 fput(pr);
  65 }
  66
  67 #ifndef CONFIG_MMU
  68 struct file *vmr_do_pr_or_file(struct vm_region *region, const char func[],
  69                                int line)
  70 {
  71         struct file *f = region->vm_file, *pr = region->vm_prfile;
  72
  73         prfile_trace(f, pr, func, line, __func__);
  74         return (f && pr) ? pr : f;
  75 }
  76
  77 void vmr_do_fput(struct vm_region *region, const char func[], int line)
  78 {
  79         struct file *f = region->vm_file, *pr = region->vm_prfile;
  80
  81         prfile_trace(f, pr, func, line, __func__);
  82         fput(f);
  83         if (f && pr)
  84                 fput(pr);
  85 }
  86 #endif /* !CONFIG_MMU */