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    • Arnd Bergmann's avatar
      llseek: automatically add .llseek fop · 6038f373
      Arnd Bergmann authored
      All file_operations should get a .llseek operation so we can make
      nonseekable_open the default for future file operations without a
      .llseek pointer.
      
      The three cases that we can automatically detect are no_llseek, seq_lseek
      and default_llseek. For cases where we can we can automatically prove that
      the file offset is always ignored, we use noop_llseek, which maintains
      the current behavior of not returning an error from a seek.
      
      New drivers should normally not use noop_llseek but instead use no_llseek
      and call nonseekable_open at open time.  Existing drivers can be converted
      to do the same when the maintainer knows for certain that no user code
      relies on calling seek on the device file.
      
      The generated code is often incorrectly indented and right now contains
      comments that clarify for each added line why a specific variant was
      chosen. In the version that gets submitted upstream, the comments will
      be gone and I will manually fix the indentation, because there does not
      seem to be a way to do that using coccinelle.
      
      Some amount of new code is currently sitting in linux-next that should get
      the same modifications, which I will do at the end of the merge window.
      
      Many thanks to Julia Lawall for helping me learn to write a semantic
      patch that does all this.
      
      ===== begin semantic patch =====
      // This adds an llseek= method to all file operations,
      // as a preparation for making no_llseek the default.
      //
      // The rules are
      // - use no_llseek explicitly if we do nonseekable_open
      // - use seq_lseek for sequential files
      // - use default_llseek if we know we access f_pos
      // - use noop_llseek if we know we don't access f_pos,
      //   but we still want to allow users to call lseek
      //
      @ open1 exists @
      identifier nested_open;
      @@
      nested_open(...)
      {
      <+...
      nonseekable_open(...)
      ...+>
      }
      
      @ open exists@
      identifier open_f;
      identifier i, f;
      identifier open1.nested_open;
      @@
      int open_f(struct inode *i, struct file *f)
      {
      <+...
      (
      nonseekable_open(...)
      |
      nested_open(...)
      )
      ...+>
      }
      
      @ read disable optional_qualifier exists @
      identifier read_f;
      identifier f, p, s, off;
      type ssize_t, size_t, loff_t;
      expression E;
      identifier func;
      @@
      ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
      {
      <+...
      (
         *off = E
      |
         *off += E
      |
         func(..., off, ...)
      |
         E = *off
      )
      ...+>
      }
      
      @ read_no_fpos disable optional_qualifier exists @
      identifier read_f;
      identifier f, p, s, off;
      type ssize_t, size_t, loff_t;
      @@
      ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
      {
      ... when != off
      }
      
      @ write @
      identifier write_f;
      identifier f, p, s, off;
      type ssize_t, size_t, loff_t;
      expression E;
      identifier func;
      @@
      ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
      {
      <+...
      (
        *off = E
      |
        *off += E
      |
        func(..., off, ...)
      |
        E = *off
      )
      ...+>
      }
      
      @ write_no_fpos @
      identifier write_f;
      identifier f, p, s, off;
      type ssize_t, size_t, loff_t;
      @@
      ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
      {
      ... when != off
      }
      
      @ fops0 @
      identifier fops;
      @@
      struct file_operations fops = {
       ...
      };
      
      @ has_llseek depends on fops0 @
      identifier fops0.fops;
      identifier llseek_f;
      @@
      struct file_operations fops = {
      ...
       .llseek = llseek_f,
      ...
      };
      
      @ has_read depends on fops0 @
      identifier fops0.fops;
      identifier read_f;
      @@
      struct file_operations fops = {
      ...
       .read = read_f,
      ...
      };
      
      @ has_write depends on fops0 @
      identifier fops0.fops;
      identifier write_f;
      @@
      struct file_operations fops = {
      ...
       .write = write_f,
      ...
      };
      
      @ has_open depends on fops0 @
      identifier fops0.fops;
      identifier open_f;
      @@
      struct file_operations fops = {
      ...
       .open = open_f,
      ...
      };
      
      // use no_llseek if we call nonseekable_open
      ////////////////////////////////////////////
      @ nonseekable1 depends on !has_llseek && has_open @
      identifier fops0.fops;
      identifier nso ~= "nonseekable_open";
      @@
      struct file_operations fops = {
      ...  .open = nso, ...
      +.llseek = no_llseek, /* nonseekable */
      };
      
      @ nonseekable2 depends on !has_llseek @
      identifier fops0.fops;
      identifier open.open_f;
      @@
      struct file_operations fops = {
      ...  .open = open_f, ...
      +.llseek = no_llseek, /* open uses nonseekable */
      };
      
      // use seq_lseek for sequential files
      /////////////////////////////////////
      @ seq depends on !has_llseek @
      identifier fops0.fops;
      identifier sr ~= "seq_read";
      @@
      struct file_operations fops = {
      ...  .read = sr, ...
      +.llseek = seq_lseek, /* we have seq_read */
      };
      
      // use default_llseek if there is a readdir
      ///////////////////////////////////////////
      @ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
      identifier fops0.fops;
      identifier readdir_e;
      @@
      // any other fop is used that changes pos
      struct file_operations fops = {
      ... .readdir = readdir_e, ...
      +.llseek = default_llseek, /* readdir is present */
      };
      
      // use default_llseek if at least one of read/write touches f_pos
      /////////////////////////////////////////////////////////////////
      @ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
      identifier fops0.fops;
      identifier read.read_f;
      @@
      // read fops use offset
      struct file_operations fops = {
      ... .read = read_f, ...
      +.llseek = default_llseek, /* read accesses f_pos */
      };
      
      @ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
      identifier fops0.fops;
      identifier write.write_f;
      @@
      // write fops use offset
      struct file_operations fops = {
      ... .write = write_f, ...
      +	.llseek = default_llseek, /* write accesses f_pos */
      };
      
      // Use noop_llseek if neither read nor write accesses f_pos
      ///////////////////////////////////////////////////////////
      
      @ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
      identifier fops0.fops;
      identifier read_no_fpos.read_f;
      identifier write_no_fpos.write_f;
      @@
      // write fops use offset
      struct file_operations fops = {
      ...
       .write = write_f,
       .read = read_f,
      ...
      +.llseek = noop_llseek, /* read and write both use no f_pos */
      };
      
      @ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
      identifier fops0.fops;
      identifier write_no_fpos.write_f;
      @@
      struct file_operations fops = {
      ... .write = write_f, ...
      +.llseek = noop_llseek, /* write uses no f_pos */
      };
      
      @ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
      identifier fops0.fops;
      identifier read_no_fpos.read_f;
      @@
      struct file_operations fops = {
      ... .read = read_f, ...
      +.llseek = noop_llseek, /* read uses no f_pos */
      };
      
      @ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
      identifier fops0.fops;
      @@
      struct file_operations fops = {
      ...
      +.llseek = noop_llseek, /* no read or write fn */
      };
      ===== End semantic patch =====
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      Cc: Julia Lawall <julia@diku.dk>
      Cc: Christoph Hellwig <hch@infradead.org>
      6038f373
  13. 25 Aug, 2010 1 commit
  14. 03 Aug, 2010 1 commit
  15. 16 Jul, 2010 2 commits
  16. 10 Mar, 2010 1 commit
  17. 04 Oct, 2009 1 commit
  18. 11 May, 2009 1 commit
  19. 16 Mar, 2009 1 commit
    • Jonathan Corbet's avatar
      Rationalize fasync return values · 60aa4924
      Jonathan Corbet authored
      Most fasync implementations do something like:
      
           return fasync_helper(...);
      
      But fasync_helper() will return a positive value at times - a feature used
      in at least one place.  Thus, a number of other drivers do:
      
           err = fasync_helper(...);
           if (err < 0)
                   return err;
           return 0;
      
      In the interests of consistency and more concise code, it makes sense to
      map positive return values onto zero where ->fasync() is called.
      
      Cc: Al Viro <viro@ZenIV.linux.org.uk>
      Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
      60aa4924
  20. 01 Nov, 2008 1 commit
    • Al Viro's avatar
      saner FASYNC handling on file close · 233e70f4
      Al Viro authored
      As it is, all instances of ->release() for files that have ->fasync()
      need to remember to evict file from fasync lists; forgetting that
      creates a hole and we actually have a bunch that *does* forget.
      
      So let's keep our lives simple - let __fput() check FASYNC in
      file->f_flags and call ->fasync() there if it's been set.  And lose that
      crap in ->release() instances - leaving it there is still valid, but we
      don't have to bother anymore.
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      233e70f4
  21. 30 Oct, 2008 1 commit
  22. 02 Jul, 2008 1 commit
  23. 01 Apr, 2008 1 commit
  24. 30 Jan, 2008 1 commit
  25. 21 Jan, 2008 1 commit
  26. 17 Jan, 2008 1 commit
    • Micah Parrish's avatar
      Input: mousedev - handle mice that use absolute coordinates · 6724f934
      Micah Parrish authored
      Devices like the HP Integrated Remote Console Virtual Mouse, which are
      standard equipment on all Proliant and Integrity servers, produce
      absolute coordinates instead of relative coordinates.  This is done to
      synchronize the position of the mouse cursor on the client desktop
      with the mouse cursor position on the server.  Mousedev is not
      designed to pass those absolute events directly to X, but it can
      translate them into relative movements.  It currently does this for
      tablet like devices and touchpads.  This patch merely tells it to also
      include a device with ABS_X, ABS_Y, and mouse buttons in its list of
      devices to process input for.
      
      This patch enables the mouse pointer to move when using the remote
      console.
      Signed-off-by: default avatarMicah Parrish <micah.parrish@hp.com>
      Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
      6724f934
  27. 19 Oct, 2007 1 commit
  28. 13 Oct, 2007 1 commit
  29. 12 Oct, 2007 1 commit
  30. 30 Aug, 2007 1 commit
  31. 10 Jul, 2007 1 commit
  32. 04 Jun, 2007 1 commit
    • Dmitry Torokhov's avatar
      Input: reduce raciness when input handlers disconnect · 1dfa2812
      Dmitry Torokhov authored
      There is a race between input handler's release() and disconnect()
      methods: when input handler disconnects it wakes up all regular
      users and then process to walk user list to wake up async. users.
      While disconnect() walks the list release() removes elements of
      the same list causing oopses.
      
      While this is not a substibute for proper locking we can reduce
      odds of getting an oops if we wake up normal readers after walking
      the list.
      Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
      1dfa2812
  33. 08 May, 2007 1 commit
  34. 03 May, 2007 1 commit
  35. 12 Apr, 2007 1 commit
    • Dmitry Torokhov's avatar
      Input: mousedev - fix sudden warps with touchpads · 0d9d93c4
      Dmitry Torokhov authored
      Pete Zaitcev reports that with his touchpad, if he lifts the finger
      and places it elsewhere, the pointer sometimes warps dramatically.
      This happens because we don't store coordinates unless we detect a
      touch so sometimes we have stale coordinates in queue (from where
      the finger left the pad) and averaging makes cursor to jump across
      the screen. The solution is to always store the latest coordinates.
      Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
      0d9d93c4