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| author | Logan Gunthorpe <logang@deltatee.com> | 2019-12-16 12:01:19 -0700 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2019-12-24 10:18:32 +0530 |
| commit | 8ad342a863590b24ce77681b7e081363fb3333f7 (patch) | |
| tree | 393b6621b115e7cc07ff47e75ab897f929902654 /include/linux/dmaengine.h | |
| parent | 11a0fd2b3baa5e4a97197b9cd990b5d05e69d669 (diff) | |
| download | lwn-8ad342a863590b24ce77681b7e081363fb3333f7.tar.gz lwn-8ad342a863590b24ce77681b7e081363fb3333f7.zip | |
dmaengine: Add reference counting to dma_device struct
Adding a reference count helps drivers to properly implement the unbind
while in use case.
References are taken and put every time a channel is allocated or freed.
Once the final reference is put, the device is removed from the
dma_device_list and a release callback function is called to signal
the driver to free the memory.
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Link: https://lore.kernel.org/r/20191216190120.21374-5-logang@deltatee.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'include/linux/dmaengine.h')
| -rw-r--r-- | include/linux/dmaengine.h | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 11b15a2e97a0..7927731e3716 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -719,9 +719,14 @@ struct dma_filter { * will just return a simple status code * @device_issue_pending: push pending transactions to hardware * @descriptor_reuse: a submitted transfer can be resubmitted after completion + * @device_release: called sometime atfer dma_async_device_unregister() is + * called and there are no further references to this structure. This + * must be implemented to free resources however many existing drivers + * do not and are therefore not safe to unbind while in use. + * */ struct dma_device { - + struct kref ref; unsigned int chancnt; unsigned int privatecnt; struct list_head channels; @@ -802,6 +807,7 @@ struct dma_device { dma_cookie_t cookie, struct dma_tx_state *txstate); void (*device_issue_pending)(struct dma_chan *chan); + void (*device_release)(struct dma_device *dev); }; static inline int dmaengine_slave_config(struct dma_chan *chan, |