[PATCH 15/32] aio: Use flush_dcache_page()

From: Kent Overstreet
Date: Wed Dec 26 2012 - 21:06:24 EST


Signed-off-by: Kent Overstreet <koverstreet@xxxxxxxxxx>
---
fs/aio.c | 45 +++++++++++++++++----------------------------
1 file changed, 17 insertions(+), 28 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index 06e1dd0..c1047c8 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -208,33 +208,15 @@ static int aio_setup_ring(struct kioctx *ctx)
ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
ring->header_length = sizeof(struct aio_ring);
kunmap_atomic(ring);
+ flush_dcache_page(info->ring_pages[0]);

return 0;
}

-
-/* aio_ring_event: returns a pointer to the event at the given index from
- * kmap_atomic(). 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_ring_event(info, nr) ({ \
- unsigned pos = (nr) + AIO_EVENTS_OFFSET; \
- struct io_event *__event; \
- __event = kmap_atomic( \
- (info)->ring_pages[pos / AIO_EVENTS_PER_PAGE]); \
- __event += pos % AIO_EVENTS_PER_PAGE; \
- __event; \
-})
-
-#define put_aio_ring_event(event) do { \
- struct io_event *__event = (event); \
- (void)__event; \
- kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK)); \
-} while(0)
-
static int kiocb_cancel(struct kioctx *ctx, struct kiocb *kiocb,
struct io_event *res)
{
@@ -645,9 +627,9 @@ void aio_complete(struct kiocb *iocb, long res, long res2)
struct kioctx *ctx = iocb->ki_ctx;
struct aio_ring_info *info;
struct aio_ring *ring;
- struct io_event *event;
+ struct io_event *ev_page, *event;
unsigned long flags;
- unsigned long tail;
+ unsigned tail, pos;

/*
* Special case handling for sync iocbs:
@@ -686,19 +668,24 @@ void aio_complete(struct kiocb *iocb, long res, long res2)
if (kiocbIsCancelled(iocb))
goto put_rq;

- ring = kmap_atomic(info->ring_pages[0]);
-
tail = info->tail;
- event = aio_ring_event(info, tail);
+ pos = tail + AIO_EVENTS_OFFSET;
+
if (++tail >= info->nr)
tail = 0;

+ ev_page = kmap_atomic(info->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
+ event = ev_page + pos % AIO_EVENTS_PER_PAGE;
+
event->obj = (u64)(unsigned long)iocb->ki_obj.user;
event->data = iocb->ki_user_data;
event->res = res;
event->res2 = res2;

- pr_debug("%p[%lu]: %p: %p %Lx %lx %lx\n",
+ kunmap_atomic(ev_page);
+ flush_dcache_page(info->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
+
+ pr_debug("%p[%u]: %p: %p %Lx %lx %lx\n",
ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data,
res, res2);

@@ -708,12 +695,13 @@ void aio_complete(struct kiocb *iocb, long res, long res2)
smp_wmb(); /* make event visible before updating tail */

info->tail = tail;
- ring->tail = tail;

- put_aio_ring_event(event);
+ ring = kmap_atomic(info->ring_pages[0]);
+ ring->tail = tail;
kunmap_atomic(ring);
+ flush_dcache_page(info->ring_pages[0]);

- pr_debug("added to ring %p at [%lu]\n", iocb, tail);
+ pr_debug("added to ring %p at [%u]\n", iocb, tail);

/*
* Check if the user asked us to deliver the result through an
@@ -805,6 +793,7 @@ static int aio_read_events_ring(struct kioctx *ctx,
ring = kmap_atomic(info->ring_pages[0]);
ring->head = head;
kunmap_atomic(ring);
+ flush_dcache_page(info->ring_pages[0]);

pr_debug("%d h%u t%u\n", ret, head, info->tail);
out:
--
1.7.12

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