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Linux 3.2 compat: rw_semaphore.wait_lock is raw
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The wait_lock member of the rw_semaphore struct became a raw_spinlock_t
in Linux 3.2 at torvalds/linux@ddb6c9b.

Wrap spin_lock_* function calls in a new spl_rwsem_* interface to
ensure type safety if raw_spinlock_t becomes architecture specific,
and to satisfy these compiler warnings:

  warning: passing argument 1 of ‘spinlock_check’
    from incompatible pointer type [enabled by default]
  note: expected ‘struct spinlock_t *’
    but argument is of type ‘struct raw_spinlock_t *’

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes: #76
Closes: openzfs/zfs#463
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@dajhorn @behlendorf
dajhorn authored and behlendorf committed Jan 12, 2012
1 parent 5f6c14b commit 588d900
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Showing 5 changed files with 206 additions and 16 deletions.
27 changes: 27 additions & 0 deletions config/spl-build.m4
View file
Original file line number Diff line number Diff line change
Expand Up @@ -85,6 +85,7 @@ AC_DEFUN([SPL_AC_CONFIG_KERNEL], [
SPL_AC_KERN_PATH_PARENT_SYMBOL
SPL_AC_2ARGS_ZLIB_DEFLATE_WORKSPACESIZE
SPL_AC_SHRINK_CONTROL_STRUCT
SPL_AC_RWSEM_SPINLOCK_IS_RAW
])

AC_DEFUN([SPL_AC_MODULE_SYMVERS], [
Expand Down Expand Up @@ -1973,3 +1974,29 @@ AC_DEFUN([SPL_AC_SHRINK_CONTROL_STRUCT], [
AC_MSG_RESULT(no)
])
])

dnl #
dnl # 3.1 API Change
dnl #
dnl # The rw_semaphore.wait_lock member was changed from spinlock_t to
dnl # raw_spinlock_t at commit ddb6c9b58a19edcfac93ac670b066c836ff729f1.
dnl #
AC_DEFUN([SPL_AC_RWSEM_SPINLOCK_IS_RAW], [
AC_MSG_CHECKING([whether struct rw_semaphore member wait_lock is raw])
tmp_flags="$EXTRA_KCFLAGS"
EXTRA_KCFLAGS="-Werror"
SPL_LINUX_TRY_COMPILE([
#include <linux/rwsem.h>
],[
struct rw_semaphore dummy_semaphore __attribute__ ((unused));
raw_spinlock_t dummy_lock __attribute__ ((unused));
dummy_semaphore.wait_lock = dummy_lock;
],[
AC_MSG_RESULT(yes)
AC_DEFINE(RWSEM_SPINLOCK_IS_RAW, 1,
[struct rw_semaphore member wait_lock is raw_spinlock_t])
],[
AC_MSG_RESULT(no)
])
EXTRA_KCFLAGS="$tmp_flags"
])
140 changes: 140 additions & 0 deletions configure
View file
Original file line number Diff line number Diff line change
Expand Up @@ -16025,6 +16025,76 @@ fi




{ $as_echo "$as_me:$LINENO: checking whether struct rw_semaphore member wait_lock is raw" >&5
$as_echo_n "checking whether struct rw_semaphore member wait_lock is raw... " >&6; }
tmp_flags="$EXTRA_KCFLAGS"
EXTRA_KCFLAGS="-Werror"


cat confdefs.h - <<_ACEOF >conftest.c
/* confdefs.h. */
_ACEOF
cat confdefs.h >>conftest.$ac_ext
cat >>conftest.$ac_ext <<_ACEOF
/* end confdefs.h. */


#include <linux/rwsem.h>

int
main (void)
{

struct rw_semaphore dummy_semaphore __attribute__ ((unused));
raw_spinlock_t dummy_lock __attribute__ ((unused));
dummy_semaphore.wait_lock = dummy_lock;

;
return 0;
}

_ACEOF


rm -Rf build && mkdir -p build
echo "obj-m := conftest.o" >build/Makefile
if { ac_try='cp conftest.c build && make modules -C $LINUX_OBJ EXTRA_CFLAGS="-Werror-implicit-function-declaration $EXTRA_KCFLAGS" $ARCH_UM M=$PWD/build'
{ (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
(eval $ac_try) 2>&5
ac_status=$?
$as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
(exit $ac_status); }; } >/dev/null && { ac_try='test -s build/conftest.o'
{ (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
(eval $ac_try) 2>&5
ac_status=$?
$as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
(exit $ac_status); }; }; then

{ $as_echo "$as_me:$LINENO: result: yes" >&5
$as_echo "yes" >&6; }

cat >>confdefs.h <<\_ACEOF
#define RWSEM_SPINLOCK_IS_RAW 1
_ACEOF


else
$as_echo "$as_me: failed program was:" >&5
sed 's/^/| /' conftest.$ac_ext >&5

{ $as_echo "$as_me:$LINENO: result: no" >&5
$as_echo "no" >&6; }



fi

rm -Rf build


EXTRA_KCFLAGS="$tmp_flags"

;;
user) ;;
all)
Expand Down Expand Up @@ -20335,6 +20405,76 @@ fi



{ $as_echo "$as_me:$LINENO: checking whether struct rw_semaphore member wait_lock is raw" >&5
$as_echo_n "checking whether struct rw_semaphore member wait_lock is raw... " >&6; }
tmp_flags="$EXTRA_KCFLAGS"
EXTRA_KCFLAGS="-Werror"


cat confdefs.h - <<_ACEOF >conftest.c
/* confdefs.h. */
_ACEOF
cat confdefs.h >>conftest.$ac_ext
cat >>conftest.$ac_ext <<_ACEOF
/* end confdefs.h. */


#include <linux/rwsem.h>

int
main (void)
{

struct rw_semaphore dummy_semaphore __attribute__ ((unused));
raw_spinlock_t dummy_lock __attribute__ ((unused));
dummy_semaphore.wait_lock = dummy_lock;

;
return 0;
}

_ACEOF


rm -Rf build && mkdir -p build
echo "obj-m := conftest.o" >build/Makefile
if { ac_try='cp conftest.c build && make modules -C $LINUX_OBJ EXTRA_CFLAGS="-Werror-implicit-function-declaration $EXTRA_KCFLAGS" $ARCH_UM M=$PWD/build'
{ (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
(eval $ac_try) 2>&5
ac_status=$?
$as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
(exit $ac_status); }; } >/dev/null && { ac_try='test -s build/conftest.o'
{ (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
(eval $ac_try) 2>&5
ac_status=$?
$as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
(exit $ac_status); }; }; then

{ $as_echo "$as_me:$LINENO: result: yes" >&5
$as_echo "yes" >&6; }

cat >>confdefs.h <<\_ACEOF
#define RWSEM_SPINLOCK_IS_RAW 1
_ACEOF


else
$as_echo "$as_me: failed program was:" >&5
sed 's/^/| /' conftest.$ac_ext >&5

{ $as_echo "$as_me:$LINENO: result: no" >&5
$as_echo "no" >&6; }



fi

rm -Rf build


EXTRA_KCFLAGS="$tmp_flags"


;;
srpm) ;;
*)
Expand Down
36 changes: 28 additions & 8 deletions include/linux/rwsem_compat.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,26 @@

#include <linux/rwsem.h>

#ifdef RWSEM_SPINLOCK_IS_RAW
#define spl_rwsem_lock_irqsave(lock, flags) \
({ \
raw_spin_lock_irqsave(lock, flags); \
})
#define spl_rwsem_unlock_irqrestore(lock, flags) \
({ \
raw_spin_unlock_irqrestore(lock, flags); \
})
#else
#define spl_rwsem_lock_irqsave(lock, flags) \
({ \
spin_lock_irqsave(lock, flags); \
})
#define spl_rwsem_unlock_irqrestore(lock, flags) \
({ \
spin_unlock_irqrestore(lock, flags); \
})
#endif /* RWSEM_SPINLOCK_IS_RAW */

#ifdef RWSEM_IS_LOCKED_TAKES_WAIT_LOCK
/*
* A race condition in rwsem_is_locked() was fixed in Linux 2.6.33 and the fix
Expand All @@ -48,14 +68,14 @@

#else

#define spl_rwsem_is_locked(rwsem) \
({ \
unsigned long _flags_; \
int _rc_; \
spin_lock_irqsave(&rwsem->wait_lock, _flags_); \
_rc_ = rwsem_is_locked(rwsem); \
spin_unlock_irqrestore(&rwsem->wait_lock, _flags_); \
_rc_; \
#define spl_rwsem_is_locked(rwsem) \
({ \
unsigned long _flags_; \
int _rc_; \
spl_rwsem_lock_irqsave(&rwsem->wait_lock, _flags_); \
_rc_ = rwsem_is_locked(rwsem); \
spl_rwsem_unlock_irqrestore(&rwsem->wait_lock, _flags_); \
_rc_; \
})

#endif /* RWSEM_IS_LOCKED_TAKES_WAIT_LOCK */
Expand Down
16 changes: 8 additions & 8 deletions include/sys/rwlock.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -52,19 +52,19 @@ spl_rw_set_owner(krwlock_t *rwp)
{
unsigned long flags;

spin_lock_irqsave(&SEM(rwp)->wait_lock, flags);
spl_rwsem_lock_irqsave(&SEM(rwp)->wait_lock, flags);
rwp->rw_owner = current;
spin_unlock_irqrestore(&SEM(rwp)->wait_lock, flags);
spl_rwsem_unlock_irqrestore(&SEM(rwp)->wait_lock, flags);
}

static inline void
spl_rw_clear_owner(krwlock_t *rwp)
{
unsigned long flags;

spin_lock_irqsave(&SEM(rwp)->wait_lock, flags);
spl_rwsem_lock_irqsave(&SEM(rwp)->wait_lock, flags);
rwp->rw_owner = NULL;
spin_unlock_irqrestore(&SEM(rwp)->wait_lock, flags);
spl_rwsem_unlock_irqrestore(&SEM(rwp)->wait_lock, flags);
}

static inline kthread_t *
Expand All @@ -73,9 +73,9 @@ rw_owner(krwlock_t *rwp)
unsigned long flags;
kthread_t *owner;

spin_lock_irqsave(&SEM(rwp)->wait_lock, flags);
spl_rwsem_lock_irqsave(&SEM(rwp)->wait_lock, flags);
owner = rwp->rw_owner;
spin_unlock_irqrestore(&SEM(rwp)->wait_lock, flags);
spl_rwsem_unlock_irqrestore(&SEM(rwp)->wait_lock, flags);

return owner;
}
Expand Down Expand Up @@ -187,14 +187,14 @@ extern int __down_write_trylock_locked(struct rw_semaphore *);
unsigned long _flags_; \
int _rc_ = 0; \
\
spin_lock_irqsave(&SEM(rwp)->wait_lock, _flags_); \
spl_rwsem_lock_irqsave(&SEM(rwp)->wait_lock, _flags_); \
if ((list_empty(&SEM(rwp)->wait_list)) && \
(SEM(rwp)->activity == 1)) { \
__up_read_locked(SEM(rwp)); \
VERIFY(_rc_ = __down_write_trylock_locked(SEM(rwp))); \
(rwp)->rw_owner = current; \
} \
spin_unlock_irqrestore(&SEM(rwp)->wait_lock, _flags_); \
spl_rwsem_unlock_irqrestore(&SEM(rwp)->wait_lock, _flags_); \
_rc_; \
})
#else
Expand Down
3 changes: 3 additions & 0 deletions spl_config.h.in
View file
Original file line number Diff line number Diff line change
Expand Up @@ -271,6 +271,9 @@
/* rwsem_is_locked() acquires sem->wait_lock */
#undef RWSEM_IS_LOCKED_TAKES_WAIT_LOCK

/* struct rw_semaphore member wait_lock is raw_spinlock_t */
#undef RWSEM_SPINLOCK_IS_RAW

/* Define the project alias string. */
#undef SPL_META_ALIAS

Expand Down

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