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compat: Get rid of (get|put)_compat_time(val|spec)

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We have two APIs for compatiblity timespec/val, with confusingly
similar names.  compat_(get|put)_time(val|spec) *do* handle the case
where COMPAT_USE_64BIT_TIME is set, whereas
(get|put)_compat_time(val|spec) do not.  This is an accident waiting
to happen.

Clean it up by favoring the full-service version; the limited version
is replaced with double-underscore versions static to kernel/compat.c.

A common pattern is to convert a struct timespec to kernel format in
an allocation on the user stack.  Unfortunately it is open-coded in
several places.  Since this allocation isn't actually needed if
COMPAT_USE_64BIT_TIME is true (since user format == kernel format)
encapsulate that whole pattern into the function
compat_convert_timespec().  An equivalent function should be written
for struct timeval if it is needed in the future.

Finally, get rid of compat_(get|put)_timeval_convert(): each was only
used once, and the latter was not even doing what the function said
(no conversion actually was being done.)  Moving the conversion into
compat_sys_settimeofday() itself makes the code much more similar to
sys_settimeofday() itself.

v3: Remove unused compat_convert_timeval().

v2: Drop bogus "const" in the destination argument for
    compat_convert_time*().

Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Mateusz Guzik <mguzik@redhat.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Tested-by: H.J. Lu <hjl.tools@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
H. Peter Anvin 2014-02-01 18:54:11 -08:00
commit 81993e81a9
7 changed files with 75 additions and 97 deletions
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23
include/linux/compat.h
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@ -140,27 +140,24 @@ struct compat_sigaction {
compat_sigset_t sa_mask __packed;
};
/*
* These functions operate strictly on struct compat_time*
*/
extern int get_compat_timespec(struct timespec *,
const struct compat_timespec __user *);
extern int put_compat_timespec(const struct timespec *,
struct compat_timespec __user *);
extern int get_compat_timeval(struct timeval *,
const struct compat_timeval __user *);
extern int put_compat_timeval(const struct timeval *,
struct compat_timeval __user *);
/*
* These functions operate on 32- or 64-bit specs depending on
* COMPAT_USE_64BIT_TIME, hence the void user pointer arguments and the
* naming as compat_get/put_ rather than get/put_compat_.
* COMPAT_USE_64BIT_TIME, hence the void user pointer arguments.
*/
extern int compat_get_timespec(struct timespec *, const void __user *);
extern int compat_put_timespec(const struct timespec *, void __user *);
extern int compat_get_timeval(struct timeval *, const void __user *);
extern int compat_put_timeval(const struct timeval *, void __user *);
/*
* This function convert a timespec if necessary and returns a *user
* space* pointer. If no conversion is necessary, it returns the
* initial pointer. NULL is a legitimate argument and will always
* output NULL.
*/
extern int compat_convert_timespec(struct timespec __user **,
const void __user *);
struct compat_iovec {
compat_uptr_t iov_base;
compat_size_t iov_len;