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author | Dan Williams <dan.j.williams@intel.com> | 2009-07-14 12:19:02 -0700 |
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committer | Dan Williams <dan.j.williams@intel.com> | 2009-08-29 19:09:27 -0700 |
commit | 95475e57113c66aac7583925736ed2e2d58c990d (patch) | |
tree | 933aa0ca3bffef5b1457c516fbe3e8690b4c4cb1 /include/linux | |
parent | af1f951eb6ef27b01cbfb3f6c21b770af4368a6d (diff) | |
download | kernel_samsung_smdk4412-95475e57113c66aac7583925736ed2e2d58c990d.zip kernel_samsung_smdk4412-95475e57113c66aac7583925736ed2e2d58c990d.tar.gz kernel_samsung_smdk4412-95475e57113c66aac7583925736ed2e2d58c990d.tar.bz2 |
async_tx: remove walk of tx->parent chain in dma_wait_for_async_tx
We currently walk the parent chain when waiting for a given tx to
complete however this walk may race with the driver cleanup routine.
The routines in async_raid6_recov.c may fall back to the synchronous
path at any point so we need to be prepared to call async_tx_quiesce()
(which calls dma_wait_for_async_tx). To remove the ->parent walk we
guarantee that every time a dependency is attached ->issue_pending() is
invoked, then we can simply poll the initial descriptor until
completion.
This also allows for a lighter weight 'issue pending' implementation as
there is no longer a requirement to iterate through all the channels'
->issue_pending() routines as long as operations have been submitted in
an ordered chain. async_tx_issue_pending() is added for this case.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'include/linux')
-rw-r--r-- | include/linux/async_tx.h | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/include/linux/async_tx.h b/include/linux/async_tx.h index 3d21a25..12a2efc 100644 --- a/include/linux/async_tx.h +++ b/include/linux/async_tx.h @@ -83,6 +83,24 @@ struct async_submit_ctl { #ifdef CONFIG_DMA_ENGINE #define async_tx_issue_pending_all dma_issue_pending_all + +/** + * async_tx_issue_pending - send pending descriptor to the hardware channel + * @tx: descriptor handle to retrieve hardware context + * + * Note: any dependent operations will have already been issued by + * async_tx_channel_switch, or (in the case of no channel switch) will + * be already pending on this channel. + */ +static inline void async_tx_issue_pending(struct dma_async_tx_descriptor *tx) +{ + if (likely(tx)) { + struct dma_chan *chan = tx->chan; + struct dma_device *dma = chan->device; + + dma->device_issue_pending(chan); + } +} #ifdef CONFIG_ARCH_HAS_ASYNC_TX_FIND_CHANNEL #include <asm/async_tx.h> #else @@ -98,6 +116,11 @@ static inline void async_tx_issue_pending_all(void) do { } while (0); } +static inline void async_tx_issue_pending(struct dma_async_tx_descriptor *tx) +{ + do { } while (0); +} + static inline struct dma_chan * async_tx_find_channel(struct async_submit_ctl *submit, enum dma_transaction_type tx_type, struct page **dst, |