dmaengine: rcar-dmac: Reject zero-length slave DMA requests
While the .device_prep_slave_sg() callback rejects empty scatterlists, it still accepts single-entry scatterlists with a zero-length segment. These may happen if a driver calls dmaengine_prep_slave_single() with a zero len parameter. The corresponding DMA request will never complete, leading to messages like: rcar-dmac e7300000.dma-controller: Channel Address Error happen and DMA timeouts. Although requesting a zero-length DMA request is a driver bug, rejecting it early eases debugging. Note that the .device_prep_dma_memcpy() callback already rejects requests to copy zero bytes. Reported-by:Eugeniu Rosca <erosca@de.adit-jv.com> Analyzed-by:
Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Signed-off-by:
Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by:
Vinod Koul <vkoul@kernel.org>
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9e5ab065
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