Re: [PATCH v4] s390/diag204: Introduce diag204 rework

[Heiko Carstens <hca@linux.ibm.com>]

On Tue, Oct 27, 2026 at 11:40:25AM +0100, Mete Durlu wrote:
> +static struct diag204_cache g_cache;

Before you send yet another version: what is "g_cache"? That seems to
be a horrible name for a global variable. What does that even stand
for? Please change the name to something more descriptive.

> +/*
> + * diag204_store() provides users data retrieved from the diag204 facility.
> + * Since diag204 is an expensive call to make, it is limited to a call per
> + * second for now.
> + * diag204_store() first checks if diag204 cache is present and valid. If the
> + * cache is valid, it copies the contents to the users buffer.
> + * If the cache is expired, it first updates the cache and then proceeds with
> + * the same copy operation.
> + *
> + * @buf: Users have to manage their own buffers by using
> + * diag204_allocate_buffer() and diag204_free_buffer().
> + *
> + * @allow_busy: If diag204 supports busy indication facility(bif), users can
> + * specify diag204 to  return BUSY instead of blocking until data becomes ready.
> + *
> + * @allow_busy_wait: If users allow diag204 to use bif, they would also get
> + * the option to specify an interruptible wait behavior by allowing busy wait.
> + * This enables users to interrupt diag204 waiting period via signals.
> + */

Is that AI generated text? That doesn't read like normal kernel documentation.
And since this looks close to kernel-doc format you could also make that
kernel-doc. But make it shorter and don't describe the implementation details.

> + * diag204_init() has to find out, which type of diagnose 204 implementation
> + * we have on the machine. Currently there are three possible scanarios:
> + *   - subcode 4   + simple data format (only one page)
> + *   - subcode 4-6 + extended data format
> + *   - subcode 4-7 + extended data format
> + *
> + * Subcode 5 is used to retrieve the size of the data, provided by subcodes
> + * 6 and 7. Subcode 7 basically has the same function as subcode 6. In addition
> + * to subcode 6 it provides also information about secondary cpus.
> + * In order to get as much information as possible, we first try
> + * subcode 7, then 6 and if both fail, we use subcode 4.
> + */

This looks like it was copied from the old code: please fix the documentation
convert to use imperative mood when you move it.