1. 11 1月, 2016 8 次提交
  2. 02 3月, 2015 1 次提交
  3. 14 2月, 2015 5 次提交
  4. 25 10月, 2013 1 次提交
  5. 28 12月, 2012 1 次提交
    • N
      [media] dvb: push down ioctl lock in dvb_usercopy · 30ad64b8
      Nikolaus Schulz 提交于
      Since most dvb ioctls wrap their real work with dvb_usercopy, the static mutex
      used in dvb_usercopy effectively is a global lock for dvb ioctls.
      Unfortunately, frontend ioctls can be blocked by the frontend thread for
      several seconds; this leads to unacceptable lock contention.  Mitigate that by
      pushing the mutex from dvb_usercopy down to the individual, device specific
      ioctls.
      There are 10 such ioctl functions using dvb_usercopy, either calling it
      directly, or via the trivial wrapper dvb_generic_ioctl. The following already
      employ their own locking and look safe:
          • dvb_demux_ioctl           (as per dvb_demux_do_ioctl)
          • dvb_dvr_ioctl             (as per dvb_dvr_do_ioctl)
          • dvb_osd_ioctl             (as per single non-trivial callee)
          • fdtv_ca_ioctl             (as per callees)
          • dvb_frontend_ioctl
      The following functions do not, and are thus changed to use a device specific
      mutex:
          • dvb_net_ioctl             (as per dvb_net_do_ioctl)
          • dvb_ca_en50221_io_ioctl   (as per dvb_ca_en50221_io_do_ioctl)
          • dvb_video_ioctl
          • dvb_audio_ioctl
          • dvb_ca_ioctl
      Signed-off-by: NNikolaus Schulz <schulz@macnetix.de>
      Signed-off-by: NMichael Krufky <mkrufky@linuxtv.org>
      Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>
      30ad64b8
  6. 16 9月, 2012 1 次提交
  7. 14 8月, 2012 1 次提交
  8. 07 7月, 2012 1 次提交
  9. 04 1月, 2012 1 次提交
  10. 21 10月, 2010 1 次提交
  11. 19 10月, 2010 1 次提交
    • A
      dvb-core: kill the big kernel lock · 72024f1e
      Arnd Bergmann 提交于
      The dvb core only uses the big kernel lock in the open
      and ioctl functions, which means it can be replaced with
      a dvb specific mutex. Fortunately, all the ioctl functions
      go through dvb_usercopy, so we can move the serialization
      in there.
      Signed-off-by: NArnd Bergmann <arnd@arndb.de>
      Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
      Cc: linux-media@vger.kernel.org
      72024f1e
  12. 15 10月, 2010 1 次提交
    • A
      llseek: automatically add .llseek fop · 6038f373
      Arnd Bergmann 提交于
      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: NArnd Bergmann <arnd@arndb.de>
      Cc: Julia Lawall <julia@diku.dk>
      Cc: Christoph Hellwig <hch@infradead.org>
      6038f373
  13. 17 5月, 2010 1 次提交
  14. 20 9月, 2009 1 次提交
  15. 16 6月, 2009 1 次提交
  16. 30 3月, 2009 1 次提交
  17. 07 1月, 2009 1 次提交
  18. 03 1月, 2009 1 次提交
  19. 30 12月, 2008 4 次提交
  20. 18 10月, 2008 1 次提交
    • D
      V4L/DVB (9227): MFE: Add multi-frontend mutual exclusion · 59b1842d
      Darron Broad 提交于
      This add frontend R/W mutual exclusion.
      Prior to this point in time it was possible to open both
      frontends simultaneously which an MFE card cannot support.
      
      In order to stop this, a delayed open is performed which
      has the following function:
      
      -  Return EBUSY after a configurable amount of time
         if a frontend is unavailable due to the other being
         in use.
      
      -  Only allow opening of a frontend if the kernel thread
         of the other has stopped.
      
      This solution was chosen to allow switching between
      frontends to work as seamlessly as possible. When both
      frontends are actually opened simultaneously then one
      will only open, but if quick switching is performed
      between one of many then the new open will succeed in
      a clean fashion rather than interrupting a kernel
      thread.
      Signed-off-by: NDarron Broad <darron@kewl.org>
      Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>
      59b1842d
  21. 17 10月, 2008 1 次提交
  22. 22 7月, 2008 1 次提交
  23. 21 6月, 2008 1 次提交
  24. 25 4月, 2008 3 次提交