[RFC PATCH] nvme: Always invalidate whole cqes[] array

[Tom Rini <trini@konsulko.com>]

On Mon, Feb 08, 2021 at 01:31:54PM +0000, Andre Przywara wrote:

> At the moment nvme_read_completion_status() tries to invidate a single
> member of the cqes[] array, which is shady as just a single entry is
> not cache line aligned.
> The structure is dictated by hardware, and with 16 bytes is smaller than
> any cache line we usually deal with. Also multiple entries need to be
> consecutive in memory, so we can't pad them to cover a whole cache line.
> 
> As a consequence we can only always invalidate all of them - U-Boot just
> uses two of them anyway. This is fine, as they are only ever read by the
> CPU (apart from the initial zeroing), so they can't become dirty.
> 
> Make this obvious by always invalidating the whole array, regardless of
> the entry number we are about to read.
> Also blow up the allocation size to cover whole cache lines, to avoid
> other heap allocations to sneak in.
> 
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
> Reviewed-by: Michael Trimarchi <michael@amarulasolutions.com>
> Tested-by: Neil Armstrong <narmstrong@baylibre.com>

Applied to u-boot/master, thanks!

-- 
Tom
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