* [PATCH] incorrect use of init_completion fixup
@ 2014-12-23 17:44 Nicholas Mc Guire
0 siblings, 0 replies; 5+ messages in thread
From: Nicholas Mc Guire @ 2014-12-23 17:44 UTC (permalink / raw)
To: Ed L. Cashin; +Cc: linux-kernel, Nicholas Mc Guire
The second init_completion call should be a reinit_completion here.
patch is against 3.18.0 linux-next
Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at>
---
drivers/block/aoe/aoecmd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c
index 422b7d8..2239513 100644
--- a/drivers/block/aoe/aoecmd.c
+++ b/drivers/block/aoe/aoecmd.c
@@ -1331,7 +1331,7 @@ aoe_ktstart(struct ktstate *k)
return -ENOMEM;
k->task = task;
wait_for_completion(&k->rendez); /* allow kthread to start */
- init_completion(&k->rendez); /* for waiting for exit later */
+ reinit_completion(&k->rendez); /* for waiting for exit later */
return 0;
}
--
1.7.10.4
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] incorrect use of init_completion fixup
2014-12-24 19:01 ` Prarit Bhargava
@ 2014-12-24 19:11 ` Nicholas Mc Guire
0 siblings, 0 replies; 5+ messages in thread
From: Nicholas Mc Guire @ 2014-12-24 19:11 UTC (permalink / raw)
To: Prarit Bhargava; +Cc: Dan Williams, Vinod Koul, dmaengine, linux-kernel
On Wed, 24 Dec 2014, Prarit Bhargava wrote:
>
>
> On 12/23/2014 12:52 PM, Nicholas Mc Guire wrote:
> > The successive init_completion calls should be reinit_completion here.
> >
>
> Hi Nicholas,
>
> I know enough about this code to break it ;) ... what condition did you hit that
> led you to this patch?
>
Was writing up documentation for completion (also posted today) and the
intended API is reinit_completion which is just resetting the counter but
not touching the related waitqueu. So the failure scenario would be
a race between accessing elements on the current wait-queue and the
init_completion reinitializing this very wait-queue.
Further if switching from init_completion -> reinit_completion brakes
anything then it really *is* broken now.
thx!
hofrat
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] incorrect use of init_completion fixup
2014-12-23 17:52 Nicholas Mc Guire
@ 2014-12-24 19:01 ` Prarit Bhargava
2014-12-24 19:11 ` Nicholas Mc Guire
0 siblings, 1 reply; 5+ messages in thread
From: Prarit Bhargava @ 2014-12-24 19:01 UTC (permalink / raw)
To: Nicholas Mc Guire; +Cc: Dan Williams, Vinod Koul, dmaengine, linux-kernel
On 12/23/2014 12:52 PM, Nicholas Mc Guire wrote:
> The successive init_completion calls should be reinit_completion here.
>
Hi Nicholas,
I know enough about this code to break it ;) ... what condition did you hit that
led you to this patch?
P.
> patch is against 3.18.0 linux-next
>
> Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at>
> ---
> drivers/dma/ioat/dma_v3.c | 4 +-
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/ioat/dma_v3.c b/drivers/dma/ioat/dma_v3.c
> index 32eae38..3dbcc42 100644
> --- a/drivers/dma/ioat/dma_v3.c
> +++ b/drivers/dma/ioat/dma_v3.c
> @@ -1353,7 +1353,7 @@ static int ioat_xor_val_self_test(struct ioatdma_device *device)
> }
>
> async_tx_ack(tx);
> - init_completion(&cmp);
> + reinit_completion(&cmp);
> tx->callback = ioat3_dma_test_callback;
> tx->callback_param = &cmp;
> cookie = tx->tx_submit(tx);
> @@ -1405,7 +1405,7 @@ static int ioat_xor_val_self_test(struct ioatdma_device *device)
> }
>
> async_tx_ack(tx);
> - init_completion(&cmp);
> + reinit_completion(&cmp);
> tx->callback = ioat3_dma_test_callback;
> tx->callback_param = &cmp;
> cookie = tx->tx_submit(tx);
> --
> 1.7.10.4
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] incorrect use of init_completion fixup
[not found] <49ea5f8dc52545d4a5df6b1ad8302410@HT17-E6.exg6.exghost.com>
@ 2014-12-24 2:14 ` Ed Cashin
0 siblings, 0 replies; 5+ messages in thread
From: Ed Cashin @ 2014-12-24 2:14 UTC (permalink / raw)
To: Nicholas Mc Guire; +Cc: linux-kernel
On Tue, Dec 23, 2014 at 12:44 PM, Nicholas Mc Guire <der.herr@hofr.at> wrote:
>
> The second init_completion call should be a reinit_completion here.
>
> patch is against 3.18.0 linux-next
>
> Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at>
> ---
> drivers/block/aoe/aoecmd.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c
> index 422b7d8..2239513 100644
> --- a/drivers/block/aoe/aoecmd.c
> +++ b/drivers/block/aoe/aoecmd.c
> @@ -1331,7 +1331,7 @@ aoe_ktstart(struct ktstate *k)
> return -ENOMEM;
> k->task = task;
> wait_for_completion(&k->rendez); /* allow kthread to start */
> - init_completion(&k->rendez); /* for waiting for exit later */
> + reinit_completion(&k->rendez); /* for waiting for exit later */
> return 0;
> }
That looks good to me, thanks.
--
Ed Cashin <ecashin@noserose.net>
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH] incorrect use of init_completion fixup
@ 2014-12-23 17:52 Nicholas Mc Guire
2014-12-24 19:01 ` Prarit Bhargava
0 siblings, 1 reply; 5+ messages in thread
From: Nicholas Mc Guire @ 2014-12-23 17:52 UTC (permalink / raw)
To: Dan Williams
Cc: Vinod Koul, Prarit Bhargava, dmaengine, linux-kernel, Nicholas Mc Guire
The successive init_completion calls should be reinit_completion here.
patch is against 3.18.0 linux-next
Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at>
---
drivers/dma/ioat/dma_v3.c | 4 +-
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/ioat/dma_v3.c b/drivers/dma/ioat/dma_v3.c
index 32eae38..3dbcc42 100644
--- a/drivers/dma/ioat/dma_v3.c
+++ b/drivers/dma/ioat/dma_v3.c
@@ -1353,7 +1353,7 @@ static int ioat_xor_val_self_test(struct ioatdma_device *device)
}
async_tx_ack(tx);
- init_completion(&cmp);
+ reinit_completion(&cmp);
tx->callback = ioat3_dma_test_callback;
tx->callback_param = &cmp;
cookie = tx->tx_submit(tx);
@@ -1405,7 +1405,7 @@ static int ioat_xor_val_self_test(struct ioatdma_device *device)
}
async_tx_ack(tx);
- init_completion(&cmp);
+ reinit_completion(&cmp);
tx->callback = ioat3_dma_test_callback;
tx->callback_param = &cmp;
cookie = tx->tx_submit(tx);
--
1.7.10.4
^ permalink raw reply related [flat|nested] 5+ messages in thread
end of thread, other threads:[~2014-12-24 19:11 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2014-12-23 17:44 [PATCH] incorrect use of init_completion fixup Nicholas Mc Guire
2014-12-23 17:52 Nicholas Mc Guire
2014-12-24 19:01 ` Prarit Bhargava
2014-12-24 19:11 ` Nicholas Mc Guire
[not found] <49ea5f8dc52545d4a5df6b1ad8302410@HT17-E6.exg6.exghost.com>
2014-12-24 2:14 ` Ed Cashin
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