<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/lib/genalloc.c, branch v5.12-rc6</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>lib/genalloc.c: change return type to unsigned long for bitmap_set_ll</title>
<updated>2021-02-26T17:41:04+00:00</updated>
<author>
<name>Huang Shijie</name>
<email>sjhuang@iluvatar.ai</email>
</author>
<published>2021-02-26T01:21:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=0e24465d3313832e82f8bd9ee2439da1367dd2e5'/>
<id>0e24465d3313832e82f8bd9ee2439da1367dd2e5</id>
<content type='text'>
Just as bitmap_clear_ll(), change return type to unsigned long
for bitmap_set_ll to avoid the possible overflow in future.

Link: https://lkml.kernel.org/r/20210105031644.2771-1-sjhuang@iluvatar.ai
Signed-off-by: Huang Shijie &lt;sjhuang@iluvatar.ai&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Just as bitmap_clear_ll(), change return type to unsigned long
for bitmap_set_ll to avoid the possible overflow in future.

Link: https://lkml.kernel.org/r/20210105031644.2771-1-sjhuang@iluvatar.ai
Signed-off-by: Huang Shijie &lt;sjhuang@iluvatar.ai&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>lib/genalloc: fix the overflow when size is too big</title>
<updated>2020-12-29T23:36:49+00:00</updated>
<author>
<name>Huang Shijie</name>
<email>sjhuang@iluvatar.ai</email>
</author>
<published>2020-12-29T23:14:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=36845663843fc59c5d794e3dc0641472e3e572da'/>
<id>36845663843fc59c5d794e3dc0641472e3e572da</id>
<content type='text'>
Some graphic card has very big memory on chip, such as 32G bytes.

In the following case, it will cause overflow:

    pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE);
    ret = gen_pool_add(pool, 0x1000000, SZ_32G, NUMA_NO_NODE);

    va = gen_pool_alloc(pool, SZ_4G);

The overflow occurs in gen_pool_alloc_algo_owner():

		....
		size = nbits &lt;&lt; order;
		....

The @nbits is "int" type, so it will overflow.
Then the gen_pool_avail() will return the wrong value.

This patch converts some "int" to "unsigned long", and
changes the compare code in while.

Link: https://lkml.kernel.org/r/20201229060657.3389-1-sjhuang@iluvatar.ai
Signed-off-by: Huang Shijie &lt;sjhuang@iluvatar.ai&gt;
Reported-by: Shi Jiasheng &lt;jiasheng.shi@iluvatar.ai&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Some graphic card has very big memory on chip, such as 32G bytes.

In the following case, it will cause overflow:

    pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE);
    ret = gen_pool_add(pool, 0x1000000, SZ_32G, NUMA_NO_NODE);

    va = gen_pool_alloc(pool, SZ_4G);

The overflow occurs in gen_pool_alloc_algo_owner():

		....
		size = nbits &lt;&lt; order;
		....

The @nbits is "int" type, so it will overflow.
Then the gen_pool_avail() will return the wrong value.

This patch converts some "int" to "unsigned long", and
changes the compare code in while.

Link: https://lkml.kernel.org/r/20201229060657.3389-1-sjhuang@iluvatar.ai
Signed-off-by: Huang Shijie &lt;sjhuang@iluvatar.ai&gt;
Reported-by: Shi Jiasheng &lt;jiasheng.shi@iluvatar.ai&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>lib/genalloc.c: rename addr_in_gen_pool to gen_pool_has_addr</title>
<updated>2019-12-05T03:44:13+00:00</updated>
<author>
<name>Huang Shijie</name>
<email>sjhuang@iluvatar.ai</email>
</author>
<published>2019-12-05T00:52:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=964975ac6677c97ae61ec9d6969dd5d03f18d1c3'/>
<id>964975ac6677c97ae61ec9d6969dd5d03f18d1c3</id>
<content type='text'>
Follow the kernel conventions, rename addr_in_gen_pool to
gen_pool_has_addr.

[sjhuang@iluvatar.ai: fix Documentation/ too]
 Link: http://lkml.kernel.org/r/20181229015914.5573-1-sjhuang@iluvatar.ai
Link: http://lkml.kernel.org/r/20181228083950.20398-1-sjhuang@iluvatar.ai
Signed-off-by: Huang Shijie &lt;sjhuang@iluvatar.ai&gt;
Reviewed-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Russell King &lt;linux@armlinux.org.uk&gt;
Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Marek Szyprowski &lt;m.szyprowski@samsung.com&gt;
Cc: Robin Murphy &lt;robin.murphy@arm.com&gt;
Cc: Stephen Rothwell &lt;sfr@canb.auug.org.au&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Follow the kernel conventions, rename addr_in_gen_pool to
gen_pool_has_addr.

[sjhuang@iluvatar.ai: fix Documentation/ too]
 Link: http://lkml.kernel.org/r/20181229015914.5573-1-sjhuang@iluvatar.ai
Link: http://lkml.kernel.org/r/20181228083950.20398-1-sjhuang@iluvatar.ai
Signed-off-by: Huang Shijie &lt;sjhuang@iluvatar.ai&gt;
Reviewed-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Russell King &lt;linux@armlinux.org.uk&gt;
Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Marek Szyprowski &lt;m.szyprowski@samsung.com&gt;
Cc: Robin Murphy &lt;robin.murphy@arm.com&gt;
Cc: Stephen Rothwell &lt;sfr@canb.auug.org.au&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>lib/genalloc.c: export symbol addr_in_gen_pool</title>
<updated>2019-12-05T03:44:13+00:00</updated>
<author>
<name>Huang Shijie</name>
<email>sjhuang@iluvatar.ai</email>
</author>
<published>2019-12-05T00:52:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=fd7eb2513f8549cf2f6b0c323377816268424bed'/>
<id>fd7eb2513f8549cf2f6b0c323377816268424bed</id>
<content type='text'>
We use addr_in_gen_pool() in a driver module.  So export it.

Link: http://lkml.kernel.org/r/20181224070622.22197-2-sjhuang@iluvatar.ai
Signed-off-by: Huang Shijie &lt;sjhuang@iluvatar.ai&gt;
Reviewed-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Alexey Skidanov &lt;alexey.skidanov@intel.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
We use addr_in_gen_pool() in a driver module.  So export it.

Link: http://lkml.kernel.org/r/20181224070622.22197-2-sjhuang@iluvatar.ai
Signed-off-by: Huang Shijie &lt;sjhuang@iluvatar.ai&gt;
Reviewed-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Alexey Skidanov &lt;alexey.skidanov@intel.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>genalloc: Fix a set of docs build warnings</title>
<updated>2019-10-07T15:10:38+00:00</updated>
<author>
<name>Jonathan Corbet</name>
<email>corbet@lwn.net</email>
</author>
<published>2019-10-03T18:40:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=ea83df73aaa3bded80e441d05ca2873c37f84e0a'/>
<id>ea83df73aaa3bded80e441d05ca2873c37f84e0a</id>
<content type='text'>
Commit 795ee30648c7 ("lib/genalloc: introduce chunk owners") made a number
of changes to the genalloc API and implementation but did not update the
documentation to match, leading to these docs build warnings:

  ./lib/genalloc.c:1: warning: 'gen_pool_add_virt' not found
  ./lib/genalloc.c:1: warning: 'gen_pool_alloc' not found
  ./lib/genalloc.c:1: warning: 'gen_pool_free' not found
  ./lib/genalloc.c:1: warning: 'gen_pool_alloc_algo' not found

Fix these by updating the docs to match new function locations and names,
and by completing the update of one kerneldoc comment.

Fixes: 795ee30648c7 ("lib/genalloc: introduce chunk owners")
Acked-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Signed-off-by: Jonathan Corbet &lt;corbet@lwn.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit 795ee30648c7 ("lib/genalloc: introduce chunk owners") made a number
of changes to the genalloc API and implementation but did not update the
documentation to match, leading to these docs build warnings:

  ./lib/genalloc.c:1: warning: 'gen_pool_add_virt' not found
  ./lib/genalloc.c:1: warning: 'gen_pool_alloc' not found
  ./lib/genalloc.c:1: warning: 'gen_pool_free' not found
  ./lib/genalloc.c:1: warning: 'gen_pool_alloc_algo' not found

Fix these by updating the docs to match new function locations and names,
and by completing the update of one kerneldoc comment.

Fixes: 795ee30648c7 ("lib/genalloc: introduce chunk owners")
Acked-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Signed-off-by: Jonathan Corbet &lt;corbet@lwn.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'dma-mapping-5.3' of git://git.infradead.org/users/hch/dma-mapping</title>
<updated>2019-07-12T22:13:55+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2019-07-12T22:13:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=9e3a25dc992dd9f3170fb643bdd95da5ca9c5576'/>
<id>9e3a25dc992dd9f3170fb643bdd95da5ca9c5576</id>
<content type='text'>
Pull dma-mapping updates from Christoph Hellwig:

 - move the USB special case that bounced DMA through a device bar into
   the USB code instead of handling it in the common DMA code (Laurentiu
   Tudor and Fredrik Noring)

 - don't dip into the global CMA pool for single page allocations
   (Nicolin Chen)

 - fix a crash when allocating memory for the atomic pool failed during
   boot (Florian Fainelli)

 - move support for MIPS-style uncached segments to the common code and
   use that for MIPS and nios2 (me)

 - make support for DMA_ATTR_NON_CONSISTENT and
   DMA_ATTR_NO_KERNEL_MAPPING generic (me)

 - convert nds32 to the generic remapping allocator (me)

* tag 'dma-mapping-5.3' of git://git.infradead.org/users/hch/dma-mapping: (29 commits)
  dma-mapping: mark dma_alloc_need_uncached as __always_inline
  MIPS: only select ARCH_HAS_UNCACHED_SEGMENT for non-coherent platforms
  usb: host: Fix excessive alignment restriction for local memory allocations
  lib/genalloc.c: Add algorithm, align and zeroed family of DMA allocators
  nios2: use the generic uncached segment support in dma-direct
  nds32: use the generic remapping allocator for coherent DMA allocations
  arc: use the generic remapping allocator for coherent DMA allocations
  dma-direct: handle DMA_ATTR_NO_KERNEL_MAPPING in common code
  dma-direct: handle DMA_ATTR_NON_CONSISTENT in common code
  dma-mapping: add a dma_alloc_need_uncached helper
  openrisc: remove the partial DMA_ATTR_NON_CONSISTENT support
  arc: remove the partial DMA_ATTR_NON_CONSISTENT support
  arm-nommu: remove the partial DMA_ATTR_NON_CONSISTENT support
  ARM: dma-mapping: allow larger DMA mask than supported
  dma-mapping: truncate dma masks to what dma_addr_t can hold
  iommu/dma: Apply dma_{alloc,free}_contiguous functions
  dma-remap: Avoid de-referencing NULL atomic_pool
  MIPS: use the generic uncached segment support in dma-direct
  dma-direct: provide generic support for uncached kernel segments
  au1100fb: fix DMA API abuse
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull dma-mapping updates from Christoph Hellwig:

 - move the USB special case that bounced DMA through a device bar into
   the USB code instead of handling it in the common DMA code (Laurentiu
   Tudor and Fredrik Noring)

 - don't dip into the global CMA pool for single page allocations
   (Nicolin Chen)

 - fix a crash when allocating memory for the atomic pool failed during
   boot (Florian Fainelli)

 - move support for MIPS-style uncached segments to the common code and
   use that for MIPS and nios2 (me)

 - make support for DMA_ATTR_NON_CONSISTENT and
   DMA_ATTR_NO_KERNEL_MAPPING generic (me)

 - convert nds32 to the generic remapping allocator (me)

* tag 'dma-mapping-5.3' of git://git.infradead.org/users/hch/dma-mapping: (29 commits)
  dma-mapping: mark dma_alloc_need_uncached as __always_inline
  MIPS: only select ARCH_HAS_UNCACHED_SEGMENT for non-coherent platforms
  usb: host: Fix excessive alignment restriction for local memory allocations
  lib/genalloc.c: Add algorithm, align and zeroed family of DMA allocators
  nios2: use the generic uncached segment support in dma-direct
  nds32: use the generic remapping allocator for coherent DMA allocations
  arc: use the generic remapping allocator for coherent DMA allocations
  dma-direct: handle DMA_ATTR_NO_KERNEL_MAPPING in common code
  dma-direct: handle DMA_ATTR_NON_CONSISTENT in common code
  dma-mapping: add a dma_alloc_need_uncached helper
  openrisc: remove the partial DMA_ATTR_NON_CONSISTENT support
  arc: remove the partial DMA_ATTR_NON_CONSISTENT support
  arm-nommu: remove the partial DMA_ATTR_NON_CONSISTENT support
  ARM: dma-mapping: allow larger DMA mask than supported
  dma-mapping: truncate dma masks to what dma_addr_t can hold
  iommu/dma: Apply dma_{alloc,free}_contiguous functions
  dma-remap: Avoid de-referencing NULL atomic_pool
  MIPS: use the generic uncached segment support in dma-direct
  dma-direct: provide generic support for uncached kernel segments
  au1100fb: fix DMA API abuse
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>lib/genalloc.c: Add algorithm, align and zeroed family of DMA allocators</title>
<updated>2019-06-28T05:56:50+00:00</updated>
<author>
<name>Fredrik Noring</name>
<email>noring@nocrew.org</email>
</author>
<published>2019-06-25T15:05:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=cf394fc5f7155c24efb584979e81427575ab3539'/>
<id>cf394fc5f7155c24efb584979e81427575ab3539</id>
<content type='text'>
Provide the algorithm option to DMA allocators as well, along with
convenience variants for zeroed and aligned memory. The following
four functions are added:

- gen_pool_dma_alloc_algo()
- gen_pool_dma_alloc_align()
- gen_pool_dma_zalloc_algo()
- gen_pool_dma_zalloc_align()

Signed-off-by: Fredrik Noring &lt;noring@nocrew.org&gt;
Tested-by: Guenter Roeck &lt;linux@roeck-us.net&gt;
Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Provide the algorithm option to DMA allocators as well, along with
convenience variants for zeroed and aligned memory. The following
four functions are added:

- gen_pool_dma_alloc_algo()
- gen_pool_dma_alloc_align()
- gen_pool_dma_zalloc_algo()
- gen_pool_dma_zalloc_align()

Signed-off-by: Fredrik Noring &lt;noring@nocrew.org&gt;
Tested-by: Guenter Roeck &lt;linux@roeck-us.net&gt;
Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 230</title>
<updated>2019-06-19T15:09:06+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2019-06-03T05:44:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=40b0b3f8fb2d8f55d13ceed41593d46689a6b496'/>
<id>40b0b3f8fb2d8f55d13ceed41593d46689a6b496</id>
<content type='text'>
Based on 2 normalized pattern(s):

  this source code is licensed under the gnu general public license
  version 2 see the file copying for more details

  this source code is licensed under general public license version 2
  see

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 52 file(s).

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Enrico Weigelt &lt;info@metux.net&gt;
Reviewed-by: Allison Randal &lt;allison@lohutok.net&gt;
Reviewed-by: Alexios Zavras &lt;alexios.zavras@intel.com&gt;
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.449021192@linutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Based on 2 normalized pattern(s):

  this source code is licensed under the gnu general public license
  version 2 see the file copying for more details

  this source code is licensed under general public license version 2
  see

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 52 file(s).

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Enrico Weigelt &lt;info@metux.net&gt;
Reviewed-by: Allison Randal &lt;allison@lohutok.net&gt;
Reviewed-by: Alexios Zavras &lt;alexios.zavras@intel.com&gt;
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.449021192@linutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>lib/genalloc: introduce chunk owners</title>
<updated>2019-06-14T03:34:56+00:00</updated>
<author>
<name>Dan Williams</name>
<email>dan.j.williams@intel.com</email>
</author>
<published>2019-06-13T22:56:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=795ee30648c708502da9df637f83c33361d68dcc'/>
<id>795ee30648c708502da9df637f83c33361d68dcc</id>
<content type='text'>
The p2pdma facility enables a provider to publish a pool of dma
addresses for a consumer to allocate.  A genpool is used internally by
p2pdma to collect dma resources, 'chunks', to be handed out to
consumers.  Whenever a consumer allocates a resource it needs to pin the
'struct dev_pagemap' instance that backs the chunk selected by
pci_alloc_p2pmem().

Currently that reference is taken globally on the entire provider
device.  That sets up a lifetime mismatch whereby the p2pdma core needs
to maintain hacks to make sure the percpu_ref is not released twice.

This lifetime mismatch also stands in the way of a fix to
devm_memremap_pages() whereby devm_memremap_pages_release() must wait for
the percpu_ref -&gt;release() callback to complete before it can proceed to
teardown pages.

So, towards fixing this situation, introduce the ability to store a 'chunk
owner' at gen_pool_add() time, and a facility to retrieve the owner at
gen_pool_{alloc,free}() time.  For p2pdma this will be used to store and
recall individual dev_pagemap reference counter instances per-chunk.

Link: http://lkml.kernel.org/r/155727338118.292046.13407378933221579644.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Reviewed-by: Ira Weiny &lt;ira.weiny@intel.com&gt;
Reviewed-by: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Cc: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Cc: "Jérôme Glisse" &lt;jglisse@redhat.com&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: "Rafael J. Wysocki" &lt;rafael@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The p2pdma facility enables a provider to publish a pool of dma
addresses for a consumer to allocate.  A genpool is used internally by
p2pdma to collect dma resources, 'chunks', to be handed out to
consumers.  Whenever a consumer allocates a resource it needs to pin the
'struct dev_pagemap' instance that backs the chunk selected by
pci_alloc_p2pmem().

Currently that reference is taken globally on the entire provider
device.  That sets up a lifetime mismatch whereby the p2pdma core needs
to maintain hacks to make sure the percpu_ref is not released twice.

This lifetime mismatch also stands in the way of a fix to
devm_memremap_pages() whereby devm_memremap_pages_release() must wait for
the percpu_ref -&gt;release() callback to complete before it can proceed to
teardown pages.

So, towards fixing this situation, introduce the ability to store a 'chunk
owner' at gen_pool_add() time, and a facility to retrieve the owner at
gen_pool_{alloc,free}() time.  For p2pdma this will be used to store and
recall individual dev_pagemap reference counter instances per-chunk.

Link: http://lkml.kernel.org/r/155727338118.292046.13407378933221579644.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Reviewed-by: Ira Weiny &lt;ira.weiny@intel.com&gt;
Reviewed-by: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Cc: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Cc: "Jérôme Glisse" &lt;jglisse@redhat.com&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: "Rafael J. Wysocki" &lt;rafael@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>lib/genalloc: add gen_pool_dma_zalloc() for zeroed DMA allocations</title>
<updated>2019-06-03T14:00:07+00:00</updated>
<author>
<name>Fredrik Noring</name>
<email>noring@nocrew.org</email>
</author>
<published>2019-05-29T10:28:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=da83a722959a82733c3ca60030cc364ca2318c5a'/>
<id>da83a722959a82733c3ca60030cc364ca2318c5a</id>
<content type='text'>
gen_pool_dma_zalloc() is a zeroed memory variant of
gen_pool_dma_alloc().  Also document the return values of both, and
indicate NULL as a "%NULL" constant.

Signed-off-by: Fredrik Noring &lt;noring@nocrew.org&gt;
Reviewed-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
gen_pool_dma_zalloc() is a zeroed memory variant of
gen_pool_dma_alloc().  Also document the return values of both, and
indicate NULL as a "%NULL" constant.

Signed-off-by: Fredrik Noring &lt;noring@nocrew.org&gt;
Reviewed-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
</pre>
</div>
</content>
</entry>
</feed>
