<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux/kernel/dma, branch v6.8</title>
<subtitle>Mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/
</subtitle>
<id>https://git.shady.money/linux/atom?h=v6.8</id>
<link rel='self' href='https://git.shady.money/linux/atom?h=v6.8'/>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/'/>
<updated>2024-01-19T00:49:34Z</updated>
<entry>
<title>Merge tag 'dma-mapping-6.8-2024-01-18' of git://git.infradead.org/users/hch/dma-mapping</title>
<updated>2024-01-19T00:49:34Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-01-19T00:49:34Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=17e232b6d2feddd0285e59dbe641c0efe67a5ee6'/>
<id>urn:sha1:17e232b6d2feddd0285e59dbe641c0efe67a5ee6</id>
<content type='text'>
Pull dma-mapping fixes from Christoph Hellwig:

 - fix kerneldoc warnings (Randy Dunlap)

 - better bounds checking in swiotlb (ZhangPeng)

* tag 'dma-mapping-6.8-2024-01-18' of git://git.infradead.org/users/hch/dma-mapping:
  dma-debug: fix kernel-doc warnings
  swiotlb: check alloc_size before the allocation of a new memory pool
</content>
</entry>
<entry>
<title>Merge tag 'char-misc-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc</title>
<updated>2024-01-18T00:47:17Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-01-18T00:47:17Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=296455ade1fdcf5f8f8c033201633b60946c589a'/>
<id>urn:sha1:296455ade1fdcf5f8f8c033201633b60946c589a</id>
<content type='text'>
Pull char/misc and other driver updates from Greg KH:
 "Here is the big set of char/misc and other driver subsystem changes
  for 6.8-rc1.

  Other than lots of binder driver changes (as you can see by the merge
  conflicts) included in here are:

   - lots of iio driver updates and additions

   - spmi driver updates

   - eeprom driver updates

   - firmware driver updates

   - ocxl driver updates

   - mhi driver updates

   - w1 driver updates

   - nvmem driver updates

   - coresight driver updates

   - platform driver remove callback api changes

   - tags.sh script updates

   - bus_type constant marking cleanups

   - lots of other small driver updates

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'char-misc-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (341 commits)
  android: removed duplicate linux/errno
  uio: Fix use-after-free in uio_open
  drivers: soc: xilinx: add check for platform
  firmware: xilinx: Export function to use in other module
  scripts/tags.sh: remove find_sources
  scripts/tags.sh: use -n to test archinclude
  scripts/tags.sh: add local annotation
  scripts/tags.sh: use more portable -path instead of -wholename
  scripts/tags.sh: Update comment (addition of gtags)
  firmware: zynqmp: Convert to platform remove callback returning void
  firmware: turris-mox-rwtm: Convert to platform remove callback returning void
  firmware: stratix10-svc: Convert to platform remove callback returning void
  firmware: stratix10-rsu: Convert to platform remove callback returning void
  firmware: raspberrypi: Convert to platform remove callback returning void
  firmware: qemu_fw_cfg: Convert to platform remove callback returning void
  firmware: mtk-adsp-ipc: Convert to platform remove callback returning void
  firmware: imx-dsp: Convert to platform remove callback returning void
  firmware: coreboot_table: Convert to platform remove callback returning void
  firmware: arm_scpi: Convert to platform remove callback returning void
  firmware: arm_scmi: Convert to platform remove callback returning void
  ...
</content>
</entry>
<entry>
<title>dma-debug: fix kernel-doc warnings</title>
<updated>2024-01-15T07:20:39Z</updated>
<author>
<name>Randy Dunlap</name>
<email>rdunlap@infradead.org</email>
</author>
<published>2024-01-14T04:46:42Z</published>
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<id>urn:sha1:7c65aa3cc072cee76f577262fbe381a111a98774</id>
<content type='text'>
Update the kernel-doc comments to catch up with the code changes and
fix the kernel-doc warnings:

debug.c:83: warning: Excess struct member 'stacktrace' description in 'dma_debug_entry'
debug.c:83: warning: Function parameter or struct member 'stack_len' not described in 'dma_debug_entry'
debug.c:83: warning: Function parameter or struct member 'stack_entries' not described in 'dma_debug_entry'

Fixes: 746017ed8d4d ("dma/debug: Simplify stracktrace retrieval")
Signed-off-by: Randy Dunlap &lt;rdunlap@infradead.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: iommu@lists.linux.dev
Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
</content>
</entry>
<entry>
<title>Merge tag 'dma-mapping-6.8-2024-01-08' of git://git.infradead.org/users/hch/dma-mapping</title>
<updated>2024-01-11T21:46:50Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-01-11T21:46:50Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=893e2f9eac9ec8d65a5ae2d99656d5e9f7bd76e2'/>
<id>urn:sha1:893e2f9eac9ec8d65a5ae2d99656d5e9f7bd76e2</id>
<content type='text'>
Pull dma-mapping updates from Christoph Hellwig:

 - reduce area lock contention for non-primary IO TLB pools (Petr
   Tesarik)

 - don't store redundant offsets in the dma_ranges stuctures (Robin
   Murphy)

 - clear dev-&gt;dma_mem when freeing per-device pools (Joakim Zhang)

* tag 'dma-mapping-6.8-2024-01-08' of git://git.infradead.org/users/hch/dma-mapping:
  dma-mapping: clear dev-&gt;dma_mem to NULL after freeing it
  swiotlb: reduce area lock contention for non-primary IO TLB pools
  dma-mapping: don't store redundant offsets
</content>
</entry>
<entry>
<title>swiotlb: check alloc_size before the allocation of a new memory pool</title>
<updated>2024-01-09T15:58:36Z</updated>
<author>
<name>ZhangPeng</name>
<email>zhangpeng362@huawei.com</email>
</author>
<published>2024-01-09T02:45:47Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=3dc2f209208dddc73ffd1d817081711343de3242'/>
<id>urn:sha1:3dc2f209208dddc73ffd1d817081711343de3242</id>
<content type='text'>
The allocation request for swiotlb contiguous memory greater than
128*2KB cannot be fulfilled because it exceeds the maximum contiguous
memory limit. If the swiotlb memory we allocate is larger than 128*2KB,
swiotlb_find_slots() will still schedule the allocation of a new memory
pool, which will increase memory overhead.

Fix it by adding a check with alloc_size no more than 128*2KB before
scheduling the allocation of a new memory pool in swiotlb_find_slots().

Signed-off-by: ZhangPeng &lt;zhangpeng362@huawei.com&gt;
Reviewed-by: Petr Tesarik &lt;petr.tesarik1@huawei-partners.com&gt;
Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
</content>
</entry>
<entry>
<title>mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER</title>
<updated>2024-01-08T23:27:15Z</updated>
<author>
<name>Kirill A. Shutemov</name>
<email>kirill.shutemov@linux.intel.com</email>
</author>
<published>2023-12-28T14:47:04Z</published>
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<id>urn:sha1:5e0a760b44417f7cadd79de2204d6247109558a0</id>
<content type='text'>
commit 23baf831a32c ("mm, treewide: redefine MAX_ORDER sanely") has
changed the definition of MAX_ORDER to be inclusive.  This has caused
issues with code that was not yet upstream and depended on the previous
definition.

To draw attention to the altered meaning of the define, rename MAX_ORDER
to MAX_PAGE_ORDER.

Link: https://lkml.kernel.org/r/20231228144704.14033-2-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>dma-debug: make dma_debug_add_bus take a const pointer</title>
<updated>2024-01-04T13:38:29Z</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2023-12-19T13:41:42Z</published>
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<id>urn:sha1:86438841e48f6361f0a6a04805b7d7813738761f</id>
<content type='text'>
The driver core now can handle a const struct bus_type pointer, and the
dma_debug_add_bus() call just passes on the pointer give to it to the
driver core, so make this pointer const as well to allow everyone to use
read-only struct bus_type pointers going forward.

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:  &lt;iommu@lists.linux.dev&gt;
Reviewed-by: Robin Murphy &lt;robin.murphy@arm.com&gt;
Link: https://lore.kernel.org/r/2023121941-dejected-nugget-681e@gregkh
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>dma-mapping: clear dev-&gt;dma_mem to NULL after freeing it</title>
<updated>2023-12-15T11:32:45Z</updated>
<author>
<name>Joakim Zhang</name>
<email>joakim.zhang@cixtech.com</email>
</author>
<published>2023-12-14T08:25:26Z</published>
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<id>urn:sha1:b07bc2347672cc8c7293c64499f1488278c5ca3d</id>
<content type='text'>
Reproduced with below sequence:
dma_declare_coherent_memory()-&gt;dma_release_coherent_memory()
-&gt;dma_declare_coherent_memory()-&gt;"return -EBUSY" error

It will return -EBUSY from the dma_assign_coherent_memory()
in dma_declare_coherent_memory(), the reason is that dev-&gt;dma_mem
pointer has not been set to NULL after it's freed.

Fixes: cf65a0f6f6ff ("dma-mapping: move all DMA mapping code to kernel/dma")
Signed-off-by: Joakim Zhang &lt;joakim.zhang@cixtech.com&gt;
Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
</content>
</entry>
<entry>
<title>swiotlb: reduce area lock contention for non-primary IO TLB pools</title>
<updated>2023-12-15T11:32:45Z</updated>
<author>
<name>Petr Tesarik</name>
<email>petr.tesarik1@huawei-partners.com</email>
</author>
<published>2023-12-01T12:13:52Z</published>
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<id>urn:sha1:55c543865b76830f524ce5ce1243266a93d06f84</id>
<content type='text'>
If multiple areas and multiple IO TLB pools exist, first iterate the
current CPU specific area in all pools. Then move to the next area index.

This is best illustrated by a diagram:

        area 0 |  area 1 | ... | area M |
pool 0    A         B              C
pool 1    D         E
...
pool N    F         G              H

Currently, each pool is searched before moving on to the next pool,
i.e. the search order is A, B ... C, D, E ... F, G ... H. With this patch,
each area is searched in all pools before moving on to the next area,
i.e. the search order is A, D ... F, B, E ... G ... C ... H.

Note that preemption is not disabled, and raw_smp_processor_id() may not
return a stable result, but it is called only once to determine the initial
area index. The search will iterate over all areas eventually, even if the
current task is preempted.

Next, some pools may have less (but not more) areas than default_nareas.
Skip such pools if the distance from the initial area index is greater than
pool-&gt;nareas. This logic ensures that for every pool the search starts in
the initial CPU's own area and never tries any area twice.

To verify performance impact, I booted the kernel with a minimum pool
size ("swiotlb=512,4,force"), so multiple pools get allocated, and I ran
these benchmarks:

- small: single-threaded I/O of 4 KiB blocks,
- big: single-threaded I/O of 64 KiB blocks,
- 4way: 4-way parallel I/O of 4 KiB blocks.

The "var" column in the tables below is the coefficient of variance over 5
runs of the test, the "diff" column is the relative difference against base
in read-write I/O bandwidth (MiB/s).

Tested on an x86 VM against a QEMU virtio SATA driver backed by a RAM-based
block device on the host:

	base	   patched
	var	var	diff
small	0.69%	0.62%	+25.4%
big	2.14%	2.27%	+25.7%
4way	2.65%	1.70%	+23.6%

Tested on a Raspberry Pi against a class-10 A1 microSD card:

	base	   patched
	var	var	diff
small	0.53%	1.96%	-0.3%
big	0.02%	0.57%	+0.8%
4way	6.17%	0.40%	+0.3%

These results confirm that there is significant performance boost in the
software IO TLB slot allocation itself. Where performance is dominated by
actual hardware, there is no measurable change.

Signed-off-by: Petr Tesarik &lt;petr.tesarik1@huawei-partners.com&gt;
Reviewed-by: Mirsad Todorovac &lt;mirsad.todorovac@alu.unizg.hr&gt;
Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
</content>
</entry>
<entry>
<title>dma-mapping: don't store redundant offsets</title>
<updated>2023-12-15T11:32:42Z</updated>
<author>
<name>Robin Murphy</name>
<email>robin.murphy@arm.com</email>
</author>
<published>2023-11-24T18:10:03Z</published>
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<id>urn:sha1:4ad4c1f394b84f9941a10aa8aaf11102478a390b</id>
<content type='text'>
A bus_dma_region necessarily stores both CPU and DMA base addresses for
a range, so there's no need to also store the difference between them.

Signed-off-by: Robin Murphy &lt;robin.murphy@arm.com&gt;
Acked-by: Rob Herring &lt;robh@kernel.org&gt;
Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
</content>
</entry>
</feed>
