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  1. Jan 04, 2011
  2. Oct 15, 2010
    • 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
  3. Sep 24, 2010
  4. Sep 07, 2010
  5. Aug 17, 2010
  6. Jul 14, 2010
  7. Jun 03, 2010
  8. May 25, 2010
  9. Mar 15, 2010
  10. Mar 02, 2010
  11. Feb 15, 2010
    • Randy Dunlap's avatar
      wireless: airo_cs build fixes · 2bf9fa69
      Randy Dunlap authored
      
      When WEXT_PRIV is not enabled, airo_cs has build errors.
      It needs to include net/iw_handler.h and it should select
      WEXT_PRIV, like the airo driver does.
      
      drivers/net/wireless/airo.c:7655: error: unknown field 'num_private' specified in initializer
      drivers/net/wireless/airo.c:7655: warning: initialization makes pointer from integer without a cast
      drivers/net/wireless/airo.c:7656: error: unknown field 'num_private_args' specified in initializer
      drivers/net/wireless/airo.c:7656: warning: excess elements in struct initializer
      drivers/net/wireless/airo.c:7656: warning: (near initialization for 'airo_handler_def')
      drivers/net/wireless/airo.c:7658: error: unknown field 'private' specified in initializer
      drivers/net/wireless/airo.c:7658: warning: initialization makes integer from pointer without a cast
      drivers/net/wireless/airo.c:7658: error: initializer element is not computable at load time
      drivers/net/wireless/airo.c:7658: error: (near initialization for 'airo_handler_def.num_standard')
      drivers/net/wireless/airo.c:7659: error: unknown field 'private_args' specified in initializer
      drivers/net/wireless/airo.c:7659: warning: initialization from incompatible pointer type
      
      Signed-off-by: default avatarRandy Dunlap <randy.dunlap@oracle.com>
      Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
      2bf9fa69
  12. Feb 12, 2010
  13. Feb 02, 2010
  14. Jan 08, 2010
  15. Dec 04, 2009
  16. Oct 27, 2009
  17. Sep 01, 2009
  18. Jul 27, 2009
  19. Jul 05, 2009
  20. Jun 13, 2009
  21. May 20, 2009
  22. May 11, 2009
  23. Apr 16, 2009
  24. Mar 30, 2009
    • Alexey Dobriyan's avatar
      proc 2/2: remove struct proc_dir_entry::owner · 99b76233
      Alexey Dobriyan authored
      Setting ->owner as done currently (pde->owner = THIS_MODULE) is racy
      as correctly noted at bug #12454. Someone can lookup entry with NULL
      ->owner, thus not pinning enything, and release it later resulting
      in module refcount underflow.
      
      We can keep ->owner and supply it at registration time like ->proc_fops
      and ->data.
      
      But this leaves ->owner as easy-manipulative field (just one C assignment)
      and somebody will forget to unpin previous/pin current module when
      switching ->owner. ->proc_fops is declared as "const" which should give
      some thoughts.
      
      ->read_proc/->write_proc were just fixed to not require ->owner for
      protection.
      
      rmmod'ed directories will be empty and return "." and ".." -- no harm.
      And directories with tricky enough readdir and lookup shouldn't be modular.
      We definitely don't want such modular code.
      
      Removing ->owner will also make PDE smaller.
      
      So, let's nuke it.
      
      Kudos to Jeff Layton for reminding about this, let's say, oversight.
      
      http://bugzilla.kernel.org/show_bug.cgi?id=12454
      
      
      
      Signed-off-by: default avatarAlexey Dobriyan <adobriyan@gmail.com>
      99b76233
  25. Mar 29, 2009
  26. Mar 21, 2009
  27. Mar 05, 2009
  28. Feb 27, 2009
  29. Feb 17, 2009
    • Hannes Eder's avatar
      drivers/net/wireless: fix sparse warnings: fix signedness · 9e05a2df
      Hannes Eder authored
      
      Fix this sparse warnings:
        drivers/net/wireless/airo.c:2102:21: warning: incorrect type in initializer (different signedness)
        drivers/net/wireless/airo.c:2126:21: warning: incorrect type in initializer (different signedness)
        drivers/net/wireless/airo.c:2167:21: warning: incorrect type in initializer (different signedness)
        drivers/net/wireless/airo.c:2191:21: warning: incorrect type in initializer (different signedness)
      
      Signed-off-by: default avatarHannes Eder <hannes@hanneseder.net>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      9e05a2df
    • Hannes Eder's avatar
      drivers/net/wireless: fix sparse warnings: symbol shadows an earlier one · 49c4a5dc
      Hannes Eder authored
      
      Impact:
        Move variable closer to usage resp.
        remove redundant variables resp.
        rename function scope variable.
      
      Fix this sparse warnings:
        drivers/net/wireless/airo.c:3840:29: warning: symbol 'i' shadows an earlier one
        drivers/net/wireless/airo.c:3751:13: originally declared here
        drivers/net/wireless/airo.c:3847:29: warning: symbol 'i' shadows an earlier one
        drivers/net/wireless/airo.c:3751:13: originally declared here
        drivers/net/wireless/airo.c:3861:21: warning: symbol 'i' shadows an earlier one
        drivers/net/wireless/airo.c:3751:13: originally declared here
        drivers/net/wireless/wavelan.c:43:13: warning: symbol 'irq' shadows an earlier one
        drivers/net/wireless/wavelan.p.h:692:17: originally declared here
      
      Signed-off-by: default avatarHannes Eder <hannes@hanneseder.net>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      49c4a5dc
  30. Jan 29, 2009
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