Re: [PATCH v6 4/5] smb/client: use bsearch() to find target in smb2_error_map_table

[David Howells <dhowells@redhat.com>]

chenxiaosong.chenxiaosong@linux.dev wrote:

> +static __always_inline int cmp_smb2_status(const void *_a, const void *_b)
> +{
> +	const struct status_to_posix_error *a = _a, *b = _b;
> +
> +	if (a->smb2_status < b->smb2_status)
> +		return -1;
> +	if (a->smb2_status > b->smb2_status)
> +		return 1;
> +	return 0;
> +}

Actually...  It's probably sufficient to do:

	static __always_inline
	int cmp_smb2_status(const void *_a, const void *_b)
	{
		const struct status_to_posix_error *a = _a, *b = _b;

		return b->smb2_status - a->smb2_status;
	}

as __inline_bsearch() only cares about the zeroness or sign of the return
value.  (Note the arguments to the subtraction might need to be flipped).

It might even better just to cast the smb status you're looking for to the key
parameter:

	__inline_bsearch((const void *)(long)status, ...);

and then do this in the comparison function:

	static __always_inline
	int cmp_smb2_status(const void *key, const void *_b)
	{
		const struct status_to_posix_error *b = _b;
		int status = (long)key;

		return b->smb2_status - status;
	}

as __inline_bsearch() doesn't attempt to dereference key.

David