Re: [Qemu-devel] [PATCH v4 3/5] megasas: bugfix

[Cao jin]

On 04/08/2016 03:16 PM, Markus Armbruster wrote:
> Please use a more descriptive title.  Suggest "megasas: Fix
>
> Cao jin <address@hidden> writes:
>
> > msi_init returns non-zero value on both failure and success
>
> This is a sentence, should end with a period.
>
> Bug's impact?  Here's my guess.
>
> msi_init() either succeeds and returns 0x50, or fails and returns a
> negative errno.  If it succeeds, we mistakenly clear
> MEGASAS_MASK_USE_MSI.  Its only use is in megasas_scsi_uninit(), via
> megasas_use_msi().  There, we fail to msi_uninit() on unrealize due to
> the bug.
>
> I figure that's harmless if we destroy the device next.  This is the
> common case.
>
> If we don't destroy it, and then realize it again, msi_init() fails,

FYI: if realize it again, I guess msi_init() won`t be executed again, 
because megasas_use_msi() will fail first.

> because there's no space at 0x50: the MSI capability we neglected to
> delete is still there.  We report the problem to the user, then realize
> the device anyway (I hate that, but it's a separate issue).

--
Yours Sincerely,

Cao jin