search for: pgmaps

Provide an internal refcounting logic if no ->ref field is provided in the pagemap passed into devm_memremap_pages so that callers don't have to reinvent it poorly. Signed-off-by: Christoph Hellwig <hch at lst.de> --- include/linux/memremap.h | 4 ++ kernel/memremap.c | 64 ++++++++++++++++++++++++------- tools/testing/nvdimm/test/iomap.c | 58

On Wed, Jun 26, 2019 at 02:27:14PM +0200, Christoph Hellwig wrote: > Provide an internal refcounting logic if no ->ref field is provided > in the pagemap passed into devm_memremap_pages so that callers don't > have to reinvent it poorly. > > Signed-off-by: Christoph Hellwig <hch at lst.de> > --- > include/linux/memremap.h | 4 ++ > kernel/memremap.c

There is only a single place where the pgmap is passed over a function call, so replace it with local variables in the places where we deal with the pgmap. Signed-off-by: Christoph Hellwig <hch at lst.de> --- mm/hmm.c | 62 ++++++++++++++++++++++++-------------------------------- 1 file changed, 27 insertions(+), 35 deletions(-) diff --git a/mm/hmm.c b/mm/hmm.c index

On Tue, Aug 06, 2019 at 07:05:42PM +0300, Christoph Hellwig wrote: > There is only a single place where the pgmap is passed over a function > call, so replace it with local variables in the places where we deal > with the pgmap. > > Signed-off-by: Christoph Hellwig <hch at lst.de> > mm/hmm.c | 62 ++++++++++++++++++++++++-------------------------------- > 1 file

The dev_pagemap is a growing too many callbacks. Move them into a separate ops structure so that they are not duplicated for multiple instances, and an attacker can't easily overwrite them. Signed-off-by: Christoph Hellwig <hch at lst.de> Reviewed-by: Logan Gunthorpe <logang at deltatee.com> Reviewed-by: Jason Gunthorpe <jgg at mellanox.com> --- drivers/dax/device.c

Hi Dan, Jérôme and Jason, below is a series that cleans up the dev_pagemap interface so that it is more easily usable, which removes the need to wrap it in hmm and thus allowing to kill a lot of code Note: this series is on top of Linux 5.2-rc5 and has some minor conflicts with the hmm tree that are easy to resolve. Diffstat summary: 32 files changed, 361 insertions(+), 1012 deletions(-) Git

Hi Dan, Jérôme and Jason, below is a series that cleans up the dev_pagemap interface so that it is more easily usable, which removes the need to wrap it in hmm and thus allowing to kill a lot of code Note: this series is on top of the rdma/hmm branch + the dev_pagemap releas fix series from Dan that went into 5.2-rc5. Git tree: git://git.infradead.org/users/hch/misc.git

On Wed, Aug 7, 2019 at 10:45 AM Jason Gunthorpe <jgg at mellanox.com> wrote: > > On Tue, Aug 06, 2019 at 07:05:42PM +0300, Christoph Hellwig wrote: > > There is only a single place where the pgmap is passed over a function > > call, so replace it with local variables in the places where we deal > > with the pgmap. > > > > Signed-off-by: Christoph Hellwig

The dev_pagemap is a growing too many callbacks. Move them into a separate ops structure so that they are not duplicated for multiple instances, and an attacker can't easily overwrite them. Signed-off-by: Christoph Hellwig <hch at lst.de> --- drivers/dax/device.c | 6 +++++- drivers/nvdimm/pmem.c | 18 +++++++++++++----- drivers/pci/p2pdma.c | 5

Hi Dan, While testing device mapper with DAX, I faced a bug with the commit: commit ad428cdb525a97d15c0349fdc80f3d58befb50df Author: Dan Williams <dan.j.williams at intel.com> Date: Wed Feb 20 21:12:50 2019 -0800 When I reverted the condition to old code[1] it worked for me. I am thinking when we map two different devices (e.g with device mapper), will start & end pfn still point

Hi Dan, While testing device mapper with DAX, I faced a bug with the commit: commit ad428cdb525a97d15c0349fdc80f3d58befb50df Author: Dan Williams <dan.j.williams at intel.com> Date: Wed Feb 20 21:12:50 2019 -0800 When I reverted the condition to old code[1] it worked for me. I am thinking when we map two different devices (e.g with device mapper), will start & end pfn still point

Passing the actual typed structure leads to more understandable code vs the actual references. Signed-off-by: Christoph Hellwig <hch at lst.de> --- drivers/dax/device.c | 7 +++---- drivers/nvdimm/pmem.c | 6 +++--- drivers/pci/p2pdma.c | 6 +++--- include/linux/memremap.h | 2 +- kernel/memremap.c | 4 ++-- mm/hmm.c

...alignment constraints somewhat save us here. The only example > I can think of a PMD not containing a uniform pgmap association for > each pte is the case when the pgmap overlaps normal dram, i.e. shares > the same 'struct memory_section' for a given span. Otherwise, distinct > pgmaps arrange to manage their own exclusive sections (and now > subsections as of v5.3). Otherwise the implementation could not > guarantee different mapping lifetimes. > > That said, this seems to want a better mechanism to determine "pfn is > ZONE_DEVICE". So I guess this pat...

The functionality is identical to the one currently open coded in p2pdma.c. Signed-off-by: Christoph Hellwig <hch at lst.de> --- drivers/pci/p2pdma.c | 57 ++++---------------------------------------- 1 file changed, 4 insertions(+), 53 deletions(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index ebd8ce3bba2e..608f84df604a 100644 --- a/drivers/pci/p2pdma.c +++

...ts somewhat save us here. The only example > > I can think of a PMD not containing a uniform pgmap association for > > each pte is the case when the pgmap overlaps normal dram, i.e. shares > > the same 'struct memory_section' for a given span. Otherwise, distinct > > pgmaps arrange to manage their own exclusive sections (and now > > subsections as of v5.3). Otherwise the implementation could not > > guarantee different mapping lifetimes. > > > > That said, this seems to want a better mechanism to determine "pfn is > > ZONE_DEVICE&qu...

Add a flags field to struct dev_pagemap to replace the altmap_valid boolean to be a little more extensible. Also add a pgmap_altmap() helper to find the optional altmap and clean up the code using the altmap using it. Signed-off-by: Christoph Hellwig <hch at lst.de> --- arch/powerpc/mm/mem.c | 10 +--------- arch/x86/mm/init_64.c | 8 ++------ drivers/nvdimm/pfn_devs.c | 3 +--

On Wed, Jun 26, 2019 at 02:27:10PM +0200, Christoph Hellwig wrote: > Just check if there is a ->page_free operation set and take care of the > static key enable, as well as the put using device managed resources. > Also check that a ->page_free is provided for the pgmaps types that > require it, and check for a valid type as well while we are at it. > > Note that this also fixes the fact that hmm never called > dev_pagemap_put_ops and thus would leave the slow path enabled forever, > even after a device driver unload or disable. > > Signed-of...

The functionality is identical to the one currently open coded in p2pdma.c. Signed-off-by: Christoph Hellwig <hch at lst.de> --- drivers/pci/p2pdma.c | 56 ++++---------------------------------------- 1 file changed, 4 insertions(+), 52 deletions(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 48a88158e46a..608f84df604a 100644 --- a/drivers/pci/p2pdma.c +++

Just check if there is a ->page_free operation set and take care of the static key enable, as well as the put using device managed resources. Also check that a ->page_free is provided for the pgmaps types that require it, and check for a valid type as well while we are at it. Note that this also fixes the fact that hmm never called dev_pagemap_put_ops and thus would leave the slow path enabled forever, even after a device driver unload or disable. Signed-off-by: Christoph Hellwig <hch at...

> diff --git a/include/linux/mm.h b/include/linux/mm.h > index 517751310dd2..5a82037a4b26 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -1093,34 +1093,6 @@ static inline bool is_zone_device_page(const struct page *page) > #ifdef CONFIG_DEV_PAGEMAP_OPS > void free_devmap_managed_page(struct page *page); > DECLARE_STATIC_KEY_FALSE(devmap_managed_key);