From: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
To: "'Zach Brown'" <zach.brown@oracle.com>,
"'Suparna Bhattacharya'" <suparna@in.ibm.com>,
"Lahaise, Benjamin C" <benjamin.c.lahaise@intel.com>
Cc: <linux-kernel@vger.kernel.org>, "'linux-aio'" <linux-aio@kvack.org>
Subject: [patch] clarify AIO_EVENTS_OFFSET constant
Date: Thu, 12 Oct 2006 17:00:24 -0700 [thread overview]
Message-ID: <000301c6ee5a$9dfae250$db34030a@amr.corp.intel.com> (raw)
A clean up patch: I think it is a lot easier to read AIO_EVENTS_OFFSET
as an offset because of aio_ring at the beginning of a head page, instead
of doing arithmetic of (event on 2nd page - event on 1st page).
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
diff -Nurp linux-2.6.18/fs/aio.c linux-2.6.18.ken/fs/aio.c
--- linux-2.6.18/fs/aio.c 2006-09-19 20:42:06.000000000 -0700
+++ linux-2.6.18.ken/fs/aio.c 2006-10-12 13:33:09.000000000 -0700
@@ -173,9 +173,8 @@ static int aio_setup_ring(struct kioctx
/* aio_ring_event: returns a pointer to the event at the given index from
* kmap_atomic(, km). Release the pointer with put_aio_ring_event();
*/
-#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
-#define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
-#define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
+#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
+#define AIO_EVENTS_OFFSET (sizeof(struct aio_ring) / sizeof(struct io_event))
#define aio_ring_event(info, nr, km) ({ \
unsigned pos = (nr) + AIO_EVENTS_OFFSET; \
next reply other threads:[~2006-10-13 0:00 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-13 0:00 Chen, Kenneth W [this message]
2006-10-13 14:22 ` Benjamin LaHaise
2006-10-13 20:38 ` Chen, Kenneth W
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