On Fri, 20 Sep 2019, Andrea Vai wrote:

> Il giorno gio, 19/09/2019 alle 14.14 +0000, Damien Le Moal ha scritto:
> > On 2019/09/19 16:01, Alan Stern wrote:
> > [...]
> > > No doubt Andrea will be happy to test your fix when it's ready.
> 
> Yes, of course.
> 
> > 
> > Hannes posted an RFC series:
> > 
> > https://www.spinics.net/lists/linux-scsi/msg133848.html
> > 
> > Andrea can try it.
> 
> Ok, but I would need some instructions please, because I am not able
> to understand how to "try it". Sorry for that.

I have attached the two patches to this email.  You should start with a 
recent kernel source tree and apply the patches by doing:

	git apply patch1 patch2

or something similar.  Then build a kernel from the new source code and 
test it.

Ultimately, if nobody can find a way to restore the sequential I/O 
behavior we had prior to commit f664a3cc17b7, that commit may have to 
be reverted.

Alan Stern