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authorBrian Behlendorf <[email protected]>2016-07-26 23:37:46 +0000
committerBrian Behlendorf <[email protected]>2016-07-29 14:17:53 -0700
commitb7c7008ba28ca926fbda929aec52f3761d72cffe (patch)
tree21c4186bf940b6ed92a72960559bac0e4be31f90 /module
parentd2f97b2a2651d8e1a6e9e1dcb07cfe8570efcfff (diff)
Linux 4.8 compat: rw_semaphore atomic_long_t count
For non-rwsem-spinlocks the "count" member was changed from a "long" to "atomic_long_t" type. A configure check has been added to detect this change along with new versions of the _rwsem_tryupgrade() function and RWSEM_COUNT() macro. See https://github.com/torvalds/linux/commit/8ee62b18 for complete details. Signed-off-by: Tim Chase <[email protected]> Signed-off-by: Chunwei Chen <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #563
Diffstat (limited to 'module')
-rw-r--r--module/spl/spl-rwlock.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/module/spl/spl-rwlock.c b/module/spl/spl-rwlock.c
index 9b356a843..77f46f2d6 100644
--- a/module/spl/spl-rwlock.c
+++ b/module/spl/spl-rwlock.c
@@ -32,7 +32,7 @@
#define DEBUG_SUBSYSTEM S_RWLOCK
-#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
+#if defined(CONFIG_RWSEM_GENERIC_SPINLOCK)
static int
__rwsem_tryupgrade(struct rw_semaphore *rwsem)
{
@@ -47,6 +47,15 @@ __rwsem_tryupgrade(struct rw_semaphore *rwsem)
spl_rwsem_unlock_irqrestore(&rwsem->wait_lock, flags);
return (ret);
}
+#elif defined(HAVE_RWSEM_ATOMIC_LONG_COUNT)
+static int
+__rwsem_tryupgrade(struct rw_semaphore *rwsem)
+{
+ long val;
+ val = atomic_long_cmpxchg(&rwsem->count, SPL_RWSEM_SINGLE_READER_VALUE,
+ SPL_RWSEM_SINGLE_WRITER_VALUE);
+ return (val == SPL_RWSEM_SINGLE_READER_VALUE);
+}
#else
static int
__rwsem_tryupgrade(struct rw_semaphore *rwsem)