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Wong" , linux-xfs@vger.kernel.org Subject: Re: [PATCH 1/5] locking: Add rwsem_is_write_locked() Message-ID: References: <20230907174705.2976191-1-willy@infradead.org> <20230907174705.2976191-2-willy@infradead.org> <2cd975ec-f868-f180-350f-b1b704118777@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2cd975ec-f868-f180-350f-b1b704118777@redhat.com> X-Rspamd-Queue-Id: 1B9BE18001D X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: yhuhynzzpcuj6atmcwoa7jubm5yo61ff X-HE-Tag: 1694115247-335711 X-HE-Meta: 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 Um2pj7kO we3OtxMUsadICeH13w25vBhxdN8K6M4ymDt+BAAFLuid92fqVQ4nJm9aPuCmujrZAF9RErTCCqyrBoCyXTMvGLT7IPl5Y9K8EBTPdKyyH85h5SFHWURaWcQJQk5eu9JSSchf8iHglnaFAU/X7u9jRZThf/wDEgifczL+cI4dAVh2PvRUiTEhqnWf+UVuCve9h5UiSp9rH40sKlEM= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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: ... #define RWSEM_READ_FAILED_MASK (RWSEM_WRITER_MASK|RWSEM_FLAG_WAITERS|\ RWSEM_FLAG_HANDOFF|RWSEM_FLAG_READFAIL) 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))