Commit Graph

63 Commits

Author SHA1 Message Date
Ira Weiny 73b0140bf0 mm/gup: change GUP fast to use flags rather than a write 'bool'
To facilitate additional options to get_user_pages_fast() change the
singular write parameter to be gup_flags.

This patch does not change any functionality.  New functionality will
follow in subsequent patches.

Some of the get_user_pages_fast() call sites were unchanged because they
already passed FOLL_WRITE or 0 for the write parameter.

NOTE: It was suggested to change the ordering of the get_user_pages_fast()
arguments to ensure that callers were converted.  This breaks the current
GUP call site convention of having the returned pages be the final
parameter.  So the suggestion was rejected.

Link: http://lkml.kernel.org/r/20190328084422.29911-4-ira.weiny@intel.com
Link: http://lkml.kernel.org/r/20190317183438.2057-4-ira.weiny@intel.com
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Mike Marshall <hubcap@omnibond.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 09:47:46 -07:00
Linus Torvalds 96d4f267e4 Remove 'type' argument from access_ok() function
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.

It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access.  But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.

A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model.  And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.

This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.

There were a couple of notable cases:

 - csky still had the old "verify_area()" name as an alias.

 - the iter_iov code had magical hardcoded knowledge of the actual
   values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
   really used it)

 - microblaze used the type argument for a debug printout

but other than those oddities this should be a total no-op patch.

I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something.  Any missed conversion should be trivially fixable, though.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-03 18:57:57 -08:00
Roman Kiryanov 6d7d725b2e platform: goldfish: pipe: Add a blank line to separate varibles and code
checkpacth: Missing a blank line after declarations

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-10-15 20:36:46 +02:00
Roman Kiryanov e6fb319330 platform: goldfish: pipe: Remove redundant casting
This casting is not required.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-10-15 20:36:46 +02:00
Roman Kiryanov 60a6e5233f platform: goldfish: pipe: Call misc_deregister if init fails
Undo effects of misc_register if driver's init fails after
misc_register.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-10-15 20:36:46 +02:00
Roman Kiryanov 08360e26f2 platform: goldfish: pipe: Move the file-scope goldfish_pipe_dev variable into the driver state
This is the last patch in the series of patches to move file-scope
variables into the driver state. This change will help to introduce
another version of the pipe driver (with different state) for the
older host interface or having several instances of this device.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-10-15 20:36:46 +02:00
Roman Kiryanov 43c2cc2864 platform: goldfish: pipe: Move the file-scope goldfish_pipe_miscdev variable into the driver state
This is a series of patches to move mutable file-scope variables
into the driver state. This change will help to introduce another
version of the pipe driver (with different state) for the older
host interface or having several instances of this device.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-10-15 20:36:46 +02:00
Roman Kiryanov c394cc3b47 platform: goldfish: pipe: Move the file-scope goldfish_interrupt_tasklet variable into the driver state
This is a series of patches to move mutable file-scope variables
into the driver state. This change will help to introduce another
version of the pipe driver (with different state) for the older
host interface or having several instances of this device.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-10-15 20:36:46 +02:00
Wei Yongjun 3790e28cdb platform: goldfish: pipe: Make symbol 'goldfish_pipe_dev' static
Fixes the following sparse warning:

drivers/platform/goldfish/goldfish_pipe.c:214:26: warning:
 symbol 'goldfish_pipe_dev' was not declared. Should it be static?

Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-25 20:38:57 +02:00
Roman Kiryanov 581ae6b722 platform: goldfish: pipe: Remove redundant header include
No symbols were used from this header.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-25 20:25:42 +02:00
Roman Kiryanov 6b979998a0 platform: goldfish: pipe: Remove redundant struct declarations
goldfish_pipe_command is defines just after declaration and
nothing refers to goldfish_pipe before it is defined.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-25 20:25:42 +02:00
Roman Kiryanov 77994c69b6 platform: goldfish: pipe: Remove a redundant blank line
The blank line is not required there.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-25 20:25:42 +02:00
Roman Kiryanov 48a2d422b5 platform: goldfish: pipe: Prevent memory corruption from several threads writing to the same variable
Move the "pages" buffer into "struct goldfish_pipe". Since we are
locking the mutex on the pipe in transfer_max_buffers, other threads
willnot be able to write into it, but other pipe instances could be
served because they have its own buffer.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-25 20:25:42 +02:00
Roman Kiryanov bfb8e83847 platform: goldfish: pipe: Replace "x==NULL" to "!x"
checkpatch: Comparison to NULL could be written "!x"

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-14 15:31:31 +02:00
Roman Kiryanov cc14057f51 platform: goldfish: pipe: Move logical ops to the end of the prev line
checkpatch: Logical continuations should be on the previous line

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-14 15:31:31 +02:00
Roman Kiryanov 52bcc7d942 platform: goldfish: pipe: Fix alignment to match parenthesis
checkpatch: Alignment should match open parenthesis.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-14 15:31:31 +02:00
Roman Kiryanov 562a74de97 platform: goldfish: pipe: Fix lines to not end an opening bracket
checkpatch: Lines should not end with a '(' or '['

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-14 15:31:31 +02:00
Roman Kiryanov 92c320b97e platform: goldfish: pipe: Rename goldfish_x to goldfish_pipe_x
Add "pipe" to the pipe related function names.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-14 15:31:30 +02:00
Roman Kiryanov a0739604f4 platform: goldfish: pipe: Remove reduntant casting to (void)
Casting to (void) is no-op.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-14 15:31:30 +02:00
Roman Kiryanov 61b38f027f platform: goldfish: pipe: Rename 'wakeBit' to 'wake_bit'
checkpatch: Avoid CamelCase

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-14 15:31:30 +02:00
Roman Kiryanov 1d1021a0f9 platform: goldfish: pipe: Remove a blank line before '}'
checkpatch: Blank lines aren't necessary before a close brace '}'

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-14 15:31:30 +02:00
Roman Kiryanov 468e62f92e platform: goldfish: pipe: Remove reduntant casting
Casting to u32 is not required here.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-14 15:31:30 +02:00
Roman Kiryanov 610a72b707 platform: goldfish: pipe: Replace two code blocks with a function call
Two function calls look cleaner because the function introduces
takes case of all bit shifting and casting.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-14 15:31:30 +02:00
Roman Kiryanov 2ed43e53e3 platform: goldfish: pipe: Remove a redundant variable
The variable was not very useful.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-14 15:31:30 +02:00
Roman Kiryanov 46928cc6ff platform: goldfish: pipe: Add blank lines to separate struct members
To improve readability and to be consistent with other
struct members.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-14 15:31:30 +02:00
Roman Kiryanov 25b97d5706 platform: goldfish: pipe: Replace pr_ with dev_ for logging
dev_ is preferred if struct device is available.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-14 15:31:30 +02:00
Roman Kiryanov 869fd5023a platform: goldfish: pipe: Replace an array of 1 with a variable
There is no reason to have an array of 1.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-14 15:31:30 +02:00
Roman Kiryanov d23069a5a5 platform: goldfish: pipe: Fail compilation if structs are too large
Since the driver provides no workaround prevent in cases if structs do
no fit into a memory page, it is better to fail complation to find about
the issue earlt instead of returning errors at runtime.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-14 15:31:30 +02:00
Roman Kiryanov 84ae527aa5 platform: goldfish: pipe: Update the comment for GFP_ATOMIC
Provide an explanation why GFP_ATOMIC is needed to prevent changing it to
other values.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-14 15:31:30 +02:00
Roman Kiryanov 95577010a4 platform: goldfish: pipe: Separate the host interface to a separate header
These are several enums that must kept in sync with the host side.
This change explicitly separates them into a dedicated header file.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-14 15:31:30 +02:00
Roman Kiryanov 53bdf6686e platform: goldfish: pipe: Move an opening brace to the next line
checkpatch: Function's opening brace has to be at the
beginning of the next line.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-14 15:31:30 +02:00
Roman Kiryanov c3c4e307db platform: goldfish: pipe: Update license
goldfish_pipe is distributed under GPL v2.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-14 15:31:30 +02:00
Roman Kiryanov ed82421565 platform: goldfish: pipe: Fix comments to fit 80 columns
Some comment lines are longer than 80 symbols.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-14 15:31:30 +02:00
Randy Dunlap ac3167257b headers: separate linux/mod_devicetable.h from linux/platform_device.h
At over 4000 #includes, <linux/platform_device.h> is the 9th most
#included header file in the Linux kernel.  It does not need
<linux/mod_devicetable.h>, so drop that header and explicitly add
<linux/mod_devicetable.h> to source files that need it.

   4146 #include <linux/platform_device.h>

After this patch, there are 225 files that use <linux/mod_devicetable.h>,
for a reduction of around 3900 times that <linux/mod_devicetable.h>
does not have to be read & parsed.

    225 #include <linux/mod_devicetable.h>

This patch was build-tested on 20 different arch-es.

It also makes these drivers SubmitChecklist#1 compliant.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kbuild test robot <lkp@intel.com> # drivers/media/platform/vimc/
Reported-by: kbuild test robot <lkp@intel.com> # drivers/pinctrl/pinctrl-u300.c
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-07 17:52:26 +02:00
Colin Ian King ea4ba866d1 goldfish_pipe: make tasklet goldfish_interrupt_tasklet static
Tasklet goldfish_interrupt_tasklet is local to the source and
does not need to be in global scope, so make it static.

Cleans up sparse warning:
symbol 'goldfish_interrupt_tasklet' was not declared. Should it be static?

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-03 13:01:57 +02:00
Linus Torvalds a9a08845e9 vfs: do bulk POLL* -> EPOLL* replacement
This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

    for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
        L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
        for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
    done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do.  But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-11 14:34:03 -08:00
Al Viro afc9a42b74 the rest of drivers/*: annotate ->poll() instances
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-11-28 11:06:58 -05:00
Greg Kroah-Hartman 069a0f32c9 Merge 4.12-rc5 into char-misc-next
We want the char/misc driver fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-12 08:18:10 +02:00
Wei Yongjun 3eff8ecd27 goldfish_pipe: use GFP_ATOMIC under spin lock
The function get_free_pipe_id_locked() is called from
goldfish_pipe_open() with a lock is held, so we should
use GFP_ATOMIC instead of GFP_KERNEL.

Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-25 18:26:11 +02:00
Colin Ian King 70caf70916 goldfish_pipe: make pipe_dev static
Make this static as it's only referenced in this source and
it does not need global scope.

Cleans up a sparse warning:

drivers/platform/goldfish/goldfish_pipe.c: warning: symbol
  'pipe_dev' was not declared. Should it be static?

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-25 18:24:03 +02:00
Greg Kroah-Hartman f563dab417 goldfish_pipe: fix build warning about using too much stack.
The new goldfish_pipe code used too much stack space in the
transfer_max_buffers() call.  As the function is serialized with a lock,
let's make the buffer static to not use the stack for the large buffer.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Cc: Yurii Zubrytskyi <zyy@google.com>
Cc: Jin Qian <jinqian@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-26 11:43:39 +02:00
Jin Qian 726ea1a8ea goldfish_pipe: An implementation of more parallel pipe
This is a driver code for a redesigned android pipe.
Currently it works for x86 and x64 emulators with the following
performance results:
  ADB push to /dev/null,
  Ubuntu,
  400 MB file,
  times are for (1 / 10 / 100) parallel adb commands
x86 adb push: (4.4s / 11.5s / 2m10s) -> (2.8s / 6s / 51s)
x64 adb push: (7s / 15s / (too long, 6m+) -> (2.7s / 6.2s / 52s)

ADB pull and push to /data/ have the same %% of speedup
More importantly, I don't see any signs of slowdowns when
run in parallel with Antutu benchmark, so it is definitely
making much better job at multithreading.

Signed-off-by: Yurii Zubrytskyi <zyy@google.com>
Signed-off-by: Jin Qian <jinqian@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-26 11:43:03 +02:00
Lorenzo Stoakes 052662cada platform: goldfish: pipe: use get_user_pages_unlocked()
Moving from get_user_pages() to get_user_pages_unlocked() simplifies the code
and takes advantage of VM_FAULT_RETRY functionality when faulting in pages.

Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-11-10 15:34:56 +01:00
Lorenzo Stoakes 768ae309a9 mm: replace get_user_pages() write/force parameters with gup_flags
This removes the 'write' and 'force' from get_user_pages() and replaces
them with 'gup_flags' to make the use of FOLL_FORCE explicit in callers
as use of this flag can result in surprising behaviour (and hence bugs)
within the mm subsystem.

Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-19 08:11:43 -07:00
Linus Torvalds cb107161df Convert straggling drivers to new six-argument get_user_pages()
Commit d4edcf0d56 ("mm/gup: Switch all callers of get_user_pages() to
not pass tsk/mm") switched get_user_pages() callers to the simpler model
where they no longer pass in the thread and mm pointer.  But since then
we've merged changes to a few drivers that re-introduce use of the old
interface.  Let's fix them up.

They continued to work fine (thanks to the truly disgusting macros
introduced in commit cde70140fed8: "mm/gup: Overload get_user_pages()
functions"), but cause unnecessary build noise.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-02 18:35:05 -05:00
Greg Kroah-Hartman bb27d4998a Merge char-misc-next into staging-next
This resolves the merge issues and confusions people were having with
the goldfish drivers due to changes for them showing up in two different
trees.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-22 14:46:24 -08:00
Shraddha Barke 1d427da1d7 Platform: goldfish: goldfish_pipe.c: Add DMA support using managed version
Coherent mapping guarantees that the device and CPU are in sync.

Signed-off-by: Shraddha Barke <shraddha.6596@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-14 17:43:05 -08:00
Dan Carpenter 5fae054c2b goldfish: locking bugs in goldfish_pipe_read_write()
We recently messed up the error handling here.  We can return with the
pipe->lock held or sometimes we unlock twice by mistake.

Fixes: 2f3be88237 ('goldfish_pipe: Pin pages to memory while copying and other cleanups')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-07 21:26:57 -08:00
Jason Hu d62f324b0a goldfish: Enable ACPI-based enumeration for android pipe
Add ACPI binding to the android pipe driver

Signed-off-by: Jason Hu <jia-cheng.hu@intel.com>
Signed-off-by: Jin Qian <jinqian@android.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28 23:34:36 -08:00
Yu Ning 4f42071c94 goldfish_pipe: Pass physical addresses to the device if supported
For reading and writing guest user space buffers, currently the kernel
sends the guest virtual address of the buffer to the pipe device. This
virtual address has to be first converted to a guest physical address.
Doing this translation on the QEMU side is inefficient and requires
additional handling when KVM is enabled, whose implementation would
either incur intrusive changes to QEMU's KVM support code or suffer
from poor performance, see commit 08c7228c50f8 ("x86-kvm: only sync
SREGS when doing address translation") of $AOSP/external/qemu for
details, and thus should be avoided if possible.

There is a TODO comment in hw/misc/android_pipe.c in the new Android
emulator source tree ($AOSP/external/qemu-android) which requests that
the translation be done on the kernel side and that physical addresses
be passed to the device instead of virtual ones. Once the QEMU-side
implementation is done, the kernel will need to support both the new
paddr-based pipe device and the old vaddr-based one (which will
continue to be used by the classic emulator). This patch achieves that
by leveraging the device version register available in the new device.

See https://android-review.googlesource.com/128280 for the QEMU-side
patch.

In addition, use the mmap semaphore (in read mode) to safeguard the
call to get_user_pages().

Signed-off-by: Yu Ning <yu.ning@intel.com>
Signed-off-by: Jin Qian <jinqian@android.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28 23:34:36 -08:00