From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Williams Subject: [PATCH 2.6.23-rc7 2/3] async_tx: fix dma_wait_for_async_tx Date: Thu, 20 Sep 2007 18:27:45 -0700 Message-ID: <20070921012745.17157.18043.stgit@dwillia2-linux.ch.intel.com> References: <20070921012141.17157.65717.stgit@dwillia2-linux.ch.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20070921012141.17157.65717.stgit@dwillia2-linux.ch.intel.com> Sender: linux-raid-owner@vger.kernel.org To: linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, neilb@suse.de Cc: akpm@linux-foundation.org, yur@emcraft.com, saeed.bishara@gmail.com, shannon.nelson@intel.com List-Id: linux-raid.ids Fix dma_wait_for_async_tx to not loop forever in the case where a dependency chain is longer than two entries. This condition will not happen with current in-kernel drivers, but fix it for future drivers. Found-by: Saeed Bishara Signed-off-by: Dan Williams --- crypto/async_tx/async_tx.c | 12 ++++++++++-- 1 files changed, 10 insertions(+), 2 deletions(-) diff --git a/crypto/async_tx/async_tx.c b/crypto/async_tx/async_tx.c index 0350071..bc18cbb 100644 --- a/crypto/async_tx/async_tx.c +++ b/crypto/async_tx/async_tx.c @@ -80,6 +80,7 @@ dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx) { enum dma_status status; struct dma_async_tx_descriptor *iter; + struct dma_async_tx_descriptor *parent; if (!tx) return DMA_SUCCESS; @@ -87,8 +88,15 @@ dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx) /* poll through the dependency chain, return when tx is complete */ do { iter = tx; - while (iter->cookie == -EBUSY) - iter = iter->parent; + + /* find the root of the unsubmitted dependency chain */ + while (iter->cookie == -EBUSY) { + parent = iter->parent; + if (parent && parent->cookie == -EBUSY) + iter = iter->parent; + else + break; + } status = dma_sync_wait(iter->chan, iter->cookie); } while (status == DMA_IN_PROGRESS || (iter != tx));