Re: [PATCH 1/5] locking: Add rwsem_is_write_locked()

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]


On 9/7/23 15:33, Matthew Wilcox wrote:
On Thu, Sep 07, 2023 at 02:05:54PM -0400, Waiman Long wrote:
On 9/7/23 13:47, Matthew Wilcox (Oracle) wrote:
+static inline int rwsem_is_write_locked(struct rw_semaphore *sem)
+	return atomic_long_read(&sem->count) & 1 /* RWSEM_WRITER_LOCKED */;
I would prefer you move the various RWSEM_* count bit macros from
kernel/locking/rwsem.c to under the !PREEMPT_RT block and directly use
RWSEM_WRITER_LOCKED instead of hardcoding a value of 1.
Just to be clear, you want the ~50 lines from:

  * On 64-bit architectures, the bit definitions of the count are:

moved from rwsem.c to rwsem.h?

Or just these four lines:

#define RWSEM_WRITER_LOCKED     (1UL << 0)
#define RWSEM_FLAG_WAITERS      (1UL << 1)
#define RWSEM_FLAG_HANDOFF      (1UL << 2)
#define RWSEM_FLAG_READFAIL     (1UL << (BITS_PER_LONG - 1))

I think just the first 3 lines will be enough. Maybe a bit of comment about these bit flags in the count atomic_long value.


[Index of Archives]     [XFS Filesystem Development (older mail)]     [Linux Filesystem Development]     [Linux Audio Users]     [Yosemite Trails]     [Linux Kernel]     [Linux RAID]     [Linux SCSI]

  Powered by Linux