Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild

Pull misc kbuild changes from Michal Marek:
 "Just a few patches on the kbuild.git#misc branch this time:

   - New Coccinelle patch by Nicholas Mc Guire
   - Existing patch fixes by Julia Lawall
   - Minor comment fix by Markus Elfring"

* 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
  Coccinelle: flag conditions with no effect
  scripts/coccicheck: Update reference for the corresponding documentation
  Coccinelle: pm_runtime: ensure relevance of pm_runtime reports
  Coccinelle: limit memdup_user transformation to GFP_KERNEL case

4 files changed, 80 insertions, 12 deletions

diff --git a/scripts/coccicheck b/scripts/coccicheck
index c92c1528a54d..ec487b8e7051 100755
--- a/scripts/coccicheck
+++ b/scripts/coccicheck
@@ -1,7 +1,7 @@
 #!/bin/bash
 # Linux kernel coccicheck
 #
-# Read Documentation/coccinelle.txt
+# Read Documentation/dev-tools/coccinelle.rst
 #
 # This script requires at least spatch
 # version 1.0.0-rc11.
diff --git a/scripts/coccinelle/api/memdup_user.cocci b/scripts/coccinelle/api/memdup_user.cocci
index c606231b0e46..2a5aea8e8487 100644
--- a/scripts/coccinelle/api/memdup_user.cocci
+++ b/scripts/coccinelle/api/memdup_user.cocci
@@ -15,11 +15,11 @@ virtual org
 virtual report
 
 @depends on patch@
-expression from,to,size,flag;
+expression from,to,size;
 identifier l1,l2;
 @@
 
--  to = \(kmalloc\|kzalloc\)(size,flag);
+-  to = \(kmalloc\|kzalloc\)(size,GFP_KERNEL);
 +  to = memdup_user(from,size);
    if (
 -      to==NULL
@@ -37,12 +37,12 @@ identifier l1,l2;
 -  }
 
 @r depends on !patch@
-expression from,to,size,flag;
+expression from,to,size;
 position p;
 statement S1,S2;
 @@
 
-*  to = \(kmalloc@p\|kzalloc@p\)(size,flag);
+*  to = \(kmalloc@p\|kzalloc@p\)(size,GFP_KERNEL);
    if (to==NULL || ...) S1
    if (copy_from_user(to, from, size) != 0)
    S2
diff --git a/scripts/coccinelle/api/pm_runtime.cocci b/scripts/coccinelle/api/pm_runtime.cocci
index 89b98a2f7a6f..d67ccf5f8227 100644
--- a/scripts/coccinelle/api/pm_runtime.cocci
+++ b/scripts/coccinelle/api/pm_runtime.cocci
@@ -17,9 +17,10 @@ virtual report
 
 @runtime_bad_err_handle exists@
 expression ret;
+position p;
 @@
 (
-ret = \(pm_runtime_idle\|
+ret@p = \(pm_runtime_idle\|
 	pm_runtime_suspend\|
 	pm_runtime_autosuspend\|
 	pm_runtime_resume\|
@@ -47,12 +48,13 @@ IS_ERR_VALUE(ret)
 //  For context mode
 //----------------------------------------------------------
 
-@depends on runtime_bad_err_handle && context@
+@depends on context@
 identifier pm_runtime_api;
 expression ret;
+position runtime_bad_err_handle.p;
 @@
 (
-ret = pm_runtime_api(...);
+ret@p = pm_runtime_api(...);
 ...
 * IS_ERR_VALUE(ret)
 ...
@@ -62,12 +64,13 @@ ret = pm_runtime_api(...);
 //  For patch mode
 //----------------------------------------------------------
 
-@depends on runtime_bad_err_handle && patch@
+@depends on patch@
 identifier pm_runtime_api;
 expression ret;
+position runtime_bad_err_handle.p;
 @@
 (
-ret = pm_runtime_api(...);
+ret@p = pm_runtime_api(...);
 ...
 - IS_ERR_VALUE(ret)
 + ret < 0
@@ -78,13 +81,14 @@ ret = pm_runtime_api(...);
 //  For org and report mode
 //----------------------------------------------------------
 
-@r depends on runtime_bad_err_handle && (org || report) exists@
+@r depends on (org || report) exists@
 position p1, p2;
 identifier pm_runtime_api;
 expression ret;
+position runtime_bad_err_handle.p;
 @@
 (
-ret = pm_runtime_api@p1(...);
+ret@p = pm_runtime_api@p1(...);
 ...
 IS_ERR_VALUE@p2(ret)
 ...
diff --git a/scripts/coccinelle/misc/cond_no_effect.cocci b/scripts/coccinelle/misc/cond_no_effect.cocci
new file mode 100644
index 000000000000..8467dbd1c465
--- /dev/null
+++ b/scripts/coccinelle/misc/cond_no_effect.cocci
@@ -0,0 +1,64 @@
+///Find conditions where if and else branch are functionally
+// identical.
+//
+// There can be false positives in cases where the positional
+// information is used (as with lockdep) or where the identity
+// is a placeholder for not yet handled cases.
+// Unfortunately there also seems to be a tendency to use
+// the last if else/else as a "default behavior" - which some
+// might consider a legitimate coding pattern. From discussion
+// on kernelnewbies though it seems that this is not really an
+// accepted pattern and if at all it would need to be commented
+//
+// In the Linux kernel it does not seem to actually report
+// false positives except for those that were documented as
+// being intentional.
+// the two known cases are:
+//   arch/sh/kernel/traps_64.c:read_opcode()
+//        } else if ((pc & 1) == 0) {
+//              /* SHcompact */
+//              /* TODO : provide handling for this.  We don't really support
+//                 user-mode SHcompact yet, and for a kernel fault, this would
+//                 have to come from a module built for SHcompact.  */
+//              return -EFAULT;
+//      } else {
+//              /* misaligned */
+//              return -EFAULT;
+//      }
+//   fs/kernfs/file.c:kernfs_fop_open()
+//       * Both paths of the branch look the same.  They're supposed to
+//       * look that way and give @of->mutex different static lockdep keys.
+//       */
+//      if (has_mmap)
+//              mutex_init(&of->mutex);
+//      else
+//              mutex_init(&of->mutex);
+//
+// All other cases look like bugs or at least lack of documentation
+//
+// Confidence: Moderate
+// Copyright: (C) 2016 Nicholas Mc Guire, OSADL.  GPLv2.
+// Comments:
+// Options: --no-includes --include-headers
+
+virtual org
+virtual report
+
+@cond@
+statement S1;
+position p;
+@@
+
+* if@p (...) S1 else S1
+
+@script:python depends on org@
+p << cond.p;
+@@
+
+cocci.print_main("WARNING: possible condition with no effect (if == else)",p)
+
+@script:python depends on report@
+p << cond.p;
+@@
+
+coccilib.report.print_report(p[0],"WARNING: possible condition with no effect (if == else)")