Re: [PATCH v3] coccinelle: api: add kvmalloc script

[Julia Lawall]

On Tue, 4 Aug 2020, Markus Elfring wrote:

> > Changes in v3:
> > - kvfree rules added
>
> I find it interesting to you found such an addition needed for this SmPL 
> script.
> I imagine that it can be helpful to support such a source code search by
> a separate script for the semantic patch language.
>
> I am curious if my patch review comments for the second version got also a bit
> of your software development attention.
>
> Another implementation detail is relevant for further clarification.
> The SmPL rules for patch generation differ in search functionality
> which is provided for other operation modes.
> Can these deviations influence the confidence level?

I see no useful information in this review, nor in the v2 review.

julia

[PATCH v3] coccinelle: api: add kvmalloc script

[Denis Efremov]

Suggest kvmalloc, kvfree instead of opencoded patterns.

Signed-off-by: Denis Efremov 
---
Changes in v2:
 - binary operator cmp added
 - NULL comparisions simplified
 - "T x" case added to !patch mode
Changes in v3:
 - kvfree rules added

 scripts/coccinelle/api/kvmalloc.cocci | 188 ++
 1 file changed, 188 insertions(+)
 create mode 100644 scripts/coccinelle/api/kvmalloc.cocci

diff --git a/scripts/coccinelle/api/kvmalloc.cocci 
b/scripts/coccinelle/api/kvmalloc.cocci
new file mode 100644
index ..2cb9281cc092
--- /dev/null
+++ b/scripts/coccinelle/api/kvmalloc.cocci
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0-only
+///
+/// Find if/else condition with kmalloc/vmalloc calls.
+/// Suggest to use kvmalloc instead. Same for kvfree.
+///
+// Confidence: High
+// Copyright: (C) 2020 Denis Efremov ISPRAS
+// Options: --no-includes --include-headers
+//
+
+virtual patch
+virtual report
+virtual org
+virtual context
+
+@initialize:python@
+@@
+filter = frozenset(['kvfree'])
+
+def relevant(p):
+return not (filter & {el.current_element for el in p})
+
+@kvmalloc depends on !patch@
+expression E, E1, size;
+binary operator cmp = {<=, <, ==, >, >=};
+identifier x;
+type T;
+position p;
+@@
+
+(
+* if (size cmp E1 || ...)@p {
+...
+*E = \(kmalloc\|kzalloc\|kcalloc\|kmalloc_node\|kzalloc_node\|
+*  kmalloc_array\|kmalloc_array_node\|kcalloc_node\)(..., size, ...)
+...
+  } else {
+...
+*E = \(vmalloc\|vzalloc\|vmalloc_node\|vzalloc_node\)(..., size, ...)
+...
+  }
+|
+* E = \(kmalloc\|kzalloc\|kcalloc\|kmalloc_node\|kzalloc_node\|
+*   kmalloc_array\|kmalloc_array_node\|kcalloc_node\)(..., size, ...)
+  ... when != E = E1
+  when != size = E1
+  when any
+* if (E == NULL)@p {
+...
+*   E = \(vmalloc\|vzalloc\|vmalloc_node\|vzalloc_node\)(..., size, ...)
+...
+  }
+|
+* T x = \(kmalloc\|kzalloc\|kcalloc\|kmalloc_node\|kzalloc_node\|
+* kmalloc_array\|kmalloc_array_node\|kcalloc_node\)(..., size, ...);
+  ... when != x = E1
+  when != size = E1
+  when any
+* if (x == NULL)@p {
+...
+*   x = \(vmalloc\|vzalloc\|vmalloc_node\|vzalloc_node\)(..., size, ...)
+...
+  }
+)
+
+@kvfree depends on !patch@
+expression E;
+position p : script:python() { relevant(p) };
+@@
+
+* if (is_vmalloc_addr(E))@p {
+...
+*   vfree(E)
+...
+  } else {
+... when != krealloc(E, ...)
+when any
+*   \(kfree\|kzfree\)(E)
+...
+  }
+
+@depends on patch@
+expression E, E1, flags, size, node;
+binary operator cmp = {<=, <, ==, >, >=};
+identifier x;
+type T;
+@@
+
+(
+- if (size cmp E1)
+-E = kmalloc(size, flags);
+- else
+-E = vmalloc(size);
++ E = kvmalloc(size, flags);
+|
+- E = kmalloc(size, flags | __GFP_NOWARN);
+- if (E == NULL)
+-   E = vmalloc(size);
++ E = kvmalloc(size, flags);
+|
+- T x = kmalloc(size, flags | __GFP_NOWARN);
+- if (x == NULL)
+-   x = vmalloc(size);
++ T x = kvmalloc(size, flags);
+|
+- if (size cmp E1)
+-E = kzalloc(size, flags);
+- else
+-E = vzalloc(size);
++ E = kvzalloc(size, flags);
+|
+- E = kzalloc(size, flags | __GFP_NOWARN);
+- if (E == NULL)
+-   E = vzalloc(size);
++ E = kvzalloc(size, flags);
+|
+- T x = kzalloc(size, flags | __GFP_NOWARN);
+- if (x == NULL)
+-   x = vzalloc(size);
++ T x = kvzalloc(size, flags);
+|
+- if (size cmp E1)
+-E = kmalloc_node(size, flags, node);
+- else
+-E = vmalloc_node(size, node);
++ E = kvmalloc_node(size, flags, node);
+|
+- E = kmalloc_node(size, flags | __GFP_NOWARN, node);
+- if (E == NULL)
+-   E = vmalloc_node(size, node);
++ E = kvmalloc_node(size, flags, node);
+|
+- T x = kmalloc_node(size, flags | __GFP_NOWARN, node);
+- if (x == NULL)
+-   x = vmalloc_node(size, node);
++ T x = kvmalloc_node(size, flags, node);
+|
+- if (size cmp E1)
+-E = kvzalloc_node(size, flags, node);
+- else
+-E = vzalloc_node(size, node);
++ E = kvzalloc_node(size, flags, node);
+|
+- E = kvzalloc_node(size, flags | __GFP_NOWARN, node);
+- if (E == NULL)
+-   E = vzalloc_node(size, node);
++ E = kvzalloc_node(size, flags, node);
+|
+- T x = kvzalloc_node(size, flags | __GFP_NOWARN, node);
+- if (x == NULL)
+-   x = vzalloc_node(size, node);
++ T x = kvzalloc_node(size, flags, node);
+)
+
+@depends on patch@
+expression E;
+position p : script:python() { relevant(p) };
+@@
+
+- if (is_vmalloc_addr(E))@p
+-   vfree(E);
+- else
+-   kfree(E);
++ kvfree(E);
+
+@script: python depends on report@
+p << kvmalloc.p;
+@@
+
+coccilib.report.print_report(p[0], "WARNING: opportunity for kvmalloc")
+
+@script: python depends on org@
+p << kvmalloc.p;
+@@
+
+coccilib.org.print_todo(p[0], "WARNING: opportunity for kvmalloc")
+
+@script: python depends on report@
+p << kvfree.p;
+@@
+
+coccilib.report.print_report(p[0], "WARNING: opportunity for kvfree")
+
+@script: python depends on org@
+p << kvfree.p;
+@@
+
+coccilib.org.print_todo(p[0], "WARNING: opportunity for kvfree")
-- 
2.26.2