c/mirror_zfs
1
0
Fork 0
mirror of https://git.proxmox.com/git/mirror_zfs.git synced 2026-05-22 18:40:43 +03:00
Code Issues Packages Projects Releases Wiki Activity

Retire rwsem_is_locked() compat

Browse Source 
Stock Linux 2.6.32 and earlier kernels contained a broken version of
rwsem_is_locked() which could return an incorrect value.  Because of
this compatibility code was added to detect the broken implementation
and replace it with our own if needed.

The fix for this issue was merged in to the mainline Linux kernel as
of 2.6.33 and the major enterprise distributions based on 2.6.32 have
all backported the fix.  Therefore there is no longer a need to carry
this code and it can be removed.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #454
This commit is contained in:
Brian Behlendorf
2015-06-03 10:42:36 -07:00
parent a876b0305e
commit 86c16c59fe
3 changed files with 2 additions and 50 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/linux/rwsem_compat.h
-24
View File
@@ -37,30 +37,6 @@
#define spl_rwsem_trylock_irqsave(lk, fl) spin_trylock_irqsave(lk, fl)
#endif /* RWSEM_SPINLOCK_IS_RAW */
/*
* Prior to Linux 2.6.33 there existed a race condition in rwsem_is_locked().
* The semaphore's activity was checked outside of the wait_lock which
* could result in some readers getting the incorrect activity value.
*
* When a kernel without this fix is detected the SPL takes responsibility
* for acquiring the wait_lock to avoid this race.
*/
#if defined(RWSEM_IS_LOCKED_TAKES_WAIT_LOCK)
#define spl_rwsem_is_locked(rwsem) rwsem_is_locked(rwsem)
#else
static inline int
spl_rwsem_is_locked(struct rw_semaphore *rwsem)
{
unsigned long flags;
int rc = 1;
if (spl_rwsem_trylock_irqsave(&rwsem->wait_lock, flags)) {
rc = rwsem_is_locked(rwsem);
spl_rwsem_unlock_irqrestore(&rwsem->wait_lock, flags);
}
return (rc);
}
#endif /* RWSEM_IS_LOCKED_TAKES_WAIT_LOCK */
#endif /* _SPL_RWSEM_COMPAT_H */
include/sys/rwlock.h
+2 -4
View File
@@ -83,15 +83,13 @@ rw_owner(krwlock_t *rwp)
static inline int
RW_READ_HELD(krwlock_t *rwp)
{
return (spl_rwsem_is_locked(SEM(rwp)) &&
rw_owner(rwp) == NULL);
return (spl_rwsem_is_locked(SEM(rwp)) && rw_owner(rwp) == NULL);
}
static inline int
RW_WRITE_HELD(krwlock_t *rwp)
{
return (spl_rwsem_is_locked(SEM(rwp)) &&
rw_owner(rwp) == current);
return (spl_rwsem_is_locked(SEM(rwp)) && rw_owner(rwp) == current);
}
static inline int