Re: [PATCH 1/2] PCI: hv: Reuse existing ITRE allocation in compose_msi_msg()

[Jeffrey Hugo]

On 5/9/2022 5:13 PM, Dexuan Cui wrote:
> > From: Jeffrey Hugo <quic_jhugo@xxxxxxxxxxx>
> > Sent: Monday, May 9, 2022 2:48 PM
> > Subject: [PATCH 1/2] PCI: hv: Reuse existing ITRE allocation in
>
> s/ITRE/IRTE. I suppose Wei can help fix this without a v2 :-)

Thanks for the review.

I have no problem sending out a V2.  Especially since you pointed out my 
mistakes on both patches.  I'll wait a little bit for any additional 
feedback, and then send out a V2.

> > compose_msi_msg()
> > ...
> > Currently if compose_msi_msg() is called multiple times, it will free any
> > previous ITRE allocation, and generate a new allocation.  While nothing
> > prevents this from occurring, it is extranious when Linux could just reuse
>
> s/extranious/extraneous
>
> > the existing allocation and avoid a bunch of overhead.
> >
> > However, when future ITRE allocations operate on blocks of MSIs instead of
>
> s/ITRE/IRTE
>
> > a single line, freeing the allocation will impact all of the lines.  This
> > could cause an issue where an allocation of N MSIs occurs, then some of
> > the lines are retargeted, and finally the allocation is freed/reallocated.
> > The freeing of the allocation removes all of the configuration for the
> > entire block, which requires all the lines to be retargeted, which might
> > not happen since some lines might already be unmasked/active.
> >
> > Signed-off-by: Jeffrey Hugo <quic_jhugo@xxxxxxxxxxx>
>
> Reviewed-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
> Tested-by: Dexuan Cui <decui@xxxxxxxxxxxxx>