Re: dm: Use common error handling code in three functions

[Mikulas Patocka <mpatocka@redhat.com>]

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On Thu, 11 Jun 2026, Markus Elfring wrote:

> >> Use additional labels so that a bit of exception handling can be better
> >> reused at the end of three if branches.
> >>
> >> This issue was detected by using the Coccinelle software.
> > 
> > Hi
> > 
> > I think that jumping into a nested block isn't good practice and it makes 
> > the code harder to read and maintain. I would redo the patches so that 
> > they jump to the end of the topmost function block, for example:
> Thanks for your constructive feedback.
> 
> Can any further adjustments become feasible for the design goal “Centralized exiting of functions”?
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/coding-style.rst?h=v7.1-rc7#n526

I think that this document is OK.

> Would you find goto chains applicable for another while?
> https://cmu-sei.github.io/secure-coding-standards/sei-cert-c-coding-standard/recommendations/memory-management-mem/mem12-c/

I think goto chains are ok if there are few variables to free.

> How do you think about to increase the application of scope-based resource management?
> https://elixir.bootlin.com/linux/v7.1-rc7/source/include/linux/cleanup.h

I am not a fan of these. I think that goto is OK if there are few 
variables to clean-up. If there is a large number of variables to clean 
up, it's better to zero-fill the whole structure and free the entries 
unconditionally (kfree does noting if it gets NULL) - see for example 
dm_integrity_ctr - it allocates the structure with kzalloc_obj and on any 
error it jumps to the label "bad" that calls dm_integrity_dtr - and 
dm_integrity_dtr frees all non-NULL entries.

Mikulas

> Regards,
> Markus