Re: [PATCH v2] Documentation: checkpatch: add UNNECESSARY_CASTS message.

On Sat, Aug 7, 2021 at 1:36 AM Dwaipayan Ray [off-list ref] wrote:

On Fri, Aug 6, 2021 at 8:49 PM Vinesh Raut [off-list ref] wrote:

quoted

Add verbose description for UNNECESSARY_CASTS message type.

Suggested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Vinesh Raut <redacted>
---
 Documentation/dev-tools/checkpatch.rst | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/Documentation/dev-tools/checkpatch.rst b/Documentation/dev-tools/checkpatch.rst
index f0956e9ea2d8..9cb6b9059fc6 100644
--- a/Documentation/dev-tools/checkpatch.rst
+++ b/Documentation/dev-tools/checkpatch.rst

@@ -268,6 +268,15 @@ Allocation style

     See: https://www.kernel.org/doc/html/latest/core-api/memory-allocation.html

+   **UNNECESSAR_CASTS**

+   **UNNECESSARY_CASTS**

quoted

+   Cast should not be done to any alloc functions.
+   Appropriate type of pointer is pick by compiler at run time

+   Appropriate type of pointer is pick by compiler at runtime

s/run time/runtime

quoted

+   Cast may hide bugs, as compiler suppresses the warning after cast.

+   If a pointer is cast (wrongly), bugs like memory corruption,
segmentation faults can occur.
+   Also, It can affect functionality of the program.

The question which arises here is what kind of bug is suppressed.
Maybe follow http://c-faq.com/malloc/mallocnocast.html as checkpatch
says to write up a paragraph on why it is bad.

quoted

+
+   See:
+   1] https://lore.kernel.org/lkml/20070808024321.GA6316@redhat.com/ (local)
+   2] https://lore.kernel.org/lkml/a5e60a2b93e10baf84af063f6c8e56402273105d.camel@perches.com/ (local)

These links are just patches that introduced the test. There is not much
information about "why" they were introduced.

Should I remove it?
And I didnt found any discussion on LKML regarding  UNNECESSARY_CASTS issue,
other than this patches.

Other than that change the enumeration type to be
uniform with the rest of the documentation maybe?
The thing followed till now is:

See:
  1. link_1
  2. link_2

+   See:
+   1. https://lore.kernel.org/lkml/20070808024321.GA6316@redhat.com/ (local)
+   2. https://lore.kernel.org/lkml/a5e60a2b93e10baf84af063f6c8e56402273105d.camel@perches.com/ (local)

Dwaipayan.

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