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Adrian Chadd 79e6882158 ath10k: go back to using dma_alloc_coherent() for firmware scratch memory
This reverts commit b057886524 ("ath10k: do not use coherent memory for
allocated device memory chunks") in 2015 which converted this allocation from
dma_map_coherent() to kzalloc() / dma_map_single().

The current problem manifests when using later model NICs with larger
(>700KiB) scratch spaces in memory.  Although the kzalloc call
succeeds, the software IOMMU TLB code (via dma_map_single()) panics
because it can't find 700KiB of linear physmem bounce buffers for DMA.
Now, this is a bit of a silly failure mode for the dma map API,
but it's what we currently have to play with.

In these cases, doing kzalloc() works fine, but the dma_map_single()
call fails.

After chatting with Linus briefly about this, it indeed should be
using dma_alloc_coherent() for doing larger device memory allocation
that requires some kind of physical address mapping.

You're not supposed to be using kzalloc and dma_map_* calls for
large memory regions, and I'm guessing not for long-held mappings
either.  Typically dma mappings should be temporary for DMA,
not long held like these.

Now, since hopefully the major annoying underlying problem has also been
addressed (ie, ath10k is no longer tears down all of these allocations
and reallocates them every time the vdevs are brought down) fragmentation
should stop being such a touchy issue.  If it is though, using
dma_alloc_coherent() use gets us access to the CMB APIs too relatively
easily and ideally we would be allocating memory early in boot for
exactly these reasons.

Signed-off-by: Adrian Chadd <adrian@FreeBSD.org>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
2017-05-31 14:13:54 +03:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-05-15 15:50:49 -07:00
block Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm 2017-05-12 15:43:10 -07:00
certs scripts/spelling.txt: add "intialise(d)" pattern and fix typo instances 2017-05-08 17:15:13 -07:00
crypto treewide: use kv[mz]alloc* rather than opencoded variants 2017-05-08 17:15:13 -07:00
Documentation mm, docs: update memory.stat description with workingset* entries 2017-05-12 15:57:16 -07:00
drivers ath10k: go back to using dma_alloc_coherent() for firmware scratch memory 2017-05-31 14:13:54 +03:00
firmware firmware/Makefile: force recompilation if makefile changes 2017-05-08 17:15:10 -07:00
fs Merge branch 'for-next' of git://git.samba.org/sfrench/cifs-2.6 2017-05-15 15:27:02 -07:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-05-15 15:50:49 -07:00
init Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-05-10 10:30:46 -07:00
ipc mm: introduce kv[mz]alloc helpers 2017-05-08 17:15:12 -07:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-05-15 15:50:49 -07:00
lib dmaengine updates for 4.12-rc1 2017-05-09 15:40:28 -07:00
mm mm: vmscan: scan until it finds eligible pages 2017-05-12 15:57:16 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-05-15 15:50:49 -07:00
samples samples/bpf: run cleanup routines when receiving SIGTERM 2017-05-11 21:43:30 -04:00
scripts Kbuild UAPI header export updates for v4.12 2017-05-10 20:45:36 -07:00
security Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-05-09 09:12:53 -07:00
sound sound fixes for 4.12-rc1 2017-05-12 12:10:38 -07:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-05-15 15:50:49 -07:00
usr initramfs: provide a way to ignore image provided by bootloader 2017-05-08 17:15:12 -07:00
virt Second round of KVM/ARM Changes for v4.12. 2017-05-09 12:51:49 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap power supply and reset changes for the v4.12 series (part 2) 2017-05-12 12:02:21 -07:00
COPYING
CREDITS avr32: remove support for AVR32 architecture 2017-05-01 09:27:15 +02:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig
MAINTAINERS Tigran has moved 2017-05-12 15:57:15 -07:00
Makefile Linux 4.12-rc1 2017-05-13 13:19:49 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.