Re: [PATCH] scsi: ufs: core: Fix setup_xfer_req invocation

From: Bart Van Assche
Date: Tue Feb 20 2024 - 13:20:00 EST


On 2/20/24 09:58, Rohit Ner wrote:
Do you propose to remove this callback altogether? This callback should
either support both transfer modes or none.

The only UFSHCI controller I know of that needs this callback is the Exynos
UFSHCI controller. As far as I know there are Exynos UFSHCI controllers that
support UFSHCI 3.0 but UFSHCI 4.0 Exynos controllers are not yet available.
Standard compliant controllers should not use the .setup_xfer_req() callback.
As you may know invoking that callback means performing an indirect function
call. Indirect function calls are slower than direct calls, especially if
speculative execution vulnerability security mitigations are enabled.

Bart.