Re: [PATCH 1/8] pmem: Initial version of persistent memory driver

From: Ross Zwisler
Date: Wed Mar 18 2015 - 13:43:17 EST


On Thu, 2015-03-05 at 13:55 +0200, Boaz Harrosh wrote:
> From: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
>
> PMEM is a new driver That supports any physical contiguous iomem range
> as a single block device. The driver has support for as many as needed
> iomem ranges each as its own device.
>
> The driver is not only good for NvDIMMs, It is good for any flat memory
> mapped device. We've used it with NvDIMMs, Kernel reserved DRAM
> (memmap= on command line), PCIE Battery backed memory cards, VM shared
> memory, and so on.
>
> The API to pmem module a single string parameter named "map"
> of the form:
> map=mapS[,mapS...]
>
> where mapS=nn[KMG]$ss[KMG],
> or mapS=nn[KMG]@ss[KMG],
>
> nn=size, ss=offset
>
> Just like the Kernel command line map && memmap parameters,
> so anything you did at grub just copy/paste to here.
>
> The "@" form is exactly the same as the "$" form only that
> at bash prompt we need to escape the "$" with \$ so also
> support the '@' char for convenience.
>
> For each specified mapS there will be a device created.
>
> [This is the accumulated version of the driver developed by
> multiple programmers. To see the real history of these
> patches see:
> git://git.open-osd.org/pmem.git
> https://github.com/01org/prd
> This patch is based on (git://git.open-osd.org/pmem.git):
> [5ccf703] SQUASHME: Don't clobber the map module param
>
> <list-of-changes>
> [boaz]
> SQUASHME: pmem: Remove unused #include headers
> SQUASHME: pmem: Request from fdisk 4k alignment
> SQUASHME: pmem: Let each device manage private memory region
> SQUASHME: pmem: Support of multiple memory regions
> SQUASHME: pmem: Micro optimization the hotpath 001
> SQUASHME: pmem: no need to copy a page at a time
> SQUASHME: pmem that 4k sector thing
> SQUASHME: pmem: Cleanliness is neat
> SQUASHME: Don't clobber the map module param
> SQUASHME: pmem: Few changes to Initial version of pmem
> SQUASHME: Changes to copyright text (trivial)
> </list-of-changes>
>
> TODO: Add Documentation/blockdev/pmem.txt
>
> Need-signed-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
> Signed-off-by: Boaz Harrosh <boaz@xxxxxxxxxxxxx>

I wrote the initial version of the PMEM driver (then called PRD for Persistent
RAM Driver) in late 2013/early 2014, and posted it on GitHub. Here's a link
to my first version:

https://github.com/01org/prd/tree/prd_3.13

Matthew Wilcox pointed Boaz to it in June of 2014, and he cloned my tree and
went off and made a bunch of changes. A few of those changes he sent back to
me, like the one I included in the patch series I recently sent for upstream
inclusion:

https://lkml.org/lkml/2015/3/16/1102

Many of the changes he did not submit back to me for review or inclusion in my
tree.

With the first patch in this series Boaz is squashing all of our changes
together, adding his copyright and trying to install himself as maintainer. I
believe this to be unacceptable.

Boaz, if you have contributions that you would like to make to PMEM, please
submit them to our mailing list (linux-nvdimm@xxxxxxxxxxxx) and we will be
happy to review them. But please don't try and steal control of my driver.

- Ross


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