On Thu, Jul 15, 2021 at 10:45:28AM -0600, Logan Gunthorpe wrote: > Hi, > > This series is spun out and expanded from my work to add P2PDMA support > to DMA map operations[1]. > > The P2PDMA work requires distinguishing different error conditions in > a map_sg operation. dma_map_sgtable() already allows for returning an > error code (where as dma_map_sg() is only allowed to return zero) > however, it currently only returns -EINVAL when a .map_sg() call returns > zero. > > This series cleans up all .map_sg() implementations to return appropriate > error codes. After the cleanup, dma_map_sg() will still return zero, > however dma_map_sgtable() will pass the error code from the .map_sg() > call. Thanks go to Martn Oliveira for doing a lot of the cleanup of the > obscure implementations. > > The patch set is based off of v5.14-rc1 and a git repo can be found > here: Have all the callers for dma_map_sg() been updated to check for error codes? If not, isn't that a pre-requisit to this patch set? >From what I see in Linus' current tree, we still have cases today where the return value of dma_map_sg() is compared with zero to detect failure, so I think that needs fixing before we start changing the dma_map_sg() implementation to return negative numbers. I also notice that there are various places that don't check the return value - and returning a negative number instead of zero may well cause random other bits to be set in fields. So, I think there's a fair amount of work to do in all the drivers before this change can be considered. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
