[PATCH 00/61] treewide: Use IS_ERR_OR_NULL over manual NULL check - refactor

[Jason Gunthorpe]

On Wed, Mar 11, 2026 at 02:40:36AM +0800, Kuan-Wei Chiu wrote:

> IMHO, the necessity of IS_ERR_OR_NULL() often highlights a confusing or
> flawed API design. It usually implies that the caller is unsure whether
> a failure results in an error pointer or a NULL pointer. 

+1

IS_ERR_OR_NULL() should always be looked on with suspicion. Very
little should be returning some tri-state 'ERR' 'NULL' 'SUCCESS'
pointer. What does the middle condition even mean? IS_ERR_OR_NULL()
implies ERR and NULL are semanticly the same, so fix the things to
always use ERR.

If you want to improve things work to get rid of the NULL checks this
script identifies. Remove ERR or NULL because only one can ever
happen, or fix the source to consistently return ERR.

Jason