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Avoid hw_desc array overrun in dw-axi-dmac
[ Upstream commit 333e11bf47
]
I have a use case where nr_buffers = 3 and in which each descriptor is composed by 3
segments, resulting in the DMA channel descs_allocated to be 9. Since axi_desc_put()
handles the hw_desc considering the descs_allocated, this scenario would result in a
kernel panic (hw_desc array will be overrun).
To fix this, the proposal is to add a new member to the axi_dma_desc structure,
where we keep the number of allocated hw_descs (axi_desc_alloc()) and use it in
axi_desc_put() to handle the hw_desc array correctly.
Additionally I propose to remove the axi_chan_start_first_queued() call after completing
the transfer, since it was identified that unbalance can occur (started descriptors can
be interrupted and transfer ignored due to DMA channel not being enabled).
Signed-off-by: Joao Pinto <jpinto@synopsys.com>
Link: https://lore.kernel.org/r/1711536564-12919-1-git-send-email-jpinto@synopsys.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
parent
10132ccf99
commit
e151ae1ee0
2 changed files with 3 additions and 4 deletions
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@ -256,6 +256,7 @@ static struct axi_dma_desc *axi_desc_alloc(u32 num)
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kfree(desc);
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return NULL;
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}
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desc->nr_hw_descs = num;
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return desc;
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}
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@ -282,7 +283,7 @@ static struct axi_dma_lli *axi_desc_get(struct axi_dma_chan *chan,
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static void axi_desc_put(struct axi_dma_desc *desc)
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{
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struct axi_dma_chan *chan = desc->chan;
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int count = atomic_read(&chan->descs_allocated);
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int count = desc->nr_hw_descs;
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struct axi_dma_hw_desc *hw_desc;
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int descs_put;
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@ -1093,9 +1094,6 @@ static void axi_chan_block_xfer_complete(struct axi_dma_chan *chan)
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/* Remove the completed descriptor from issued list before completing */
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list_del(&vd->node);
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vchan_cookie_complete(vd);
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/* Submit queued descriptors after processing the completed ones */
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axi_chan_start_first_queued(chan);
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}
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out:
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@ -104,6 +104,7 @@ struct axi_dma_desc {
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u32 completed_blocks;
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u32 length;
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u32 period_len;
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u32 nr_hw_descs;
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};
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struct axi_dma_chan_config {
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