diff options
| author | Christoph Hellwig <hch@lst.de> | 2025-05-05 10:01:45 +0300 |
|---|---|---|
| committer | Marek Szyprowski <m.szyprowski@samsung.com> | 2025-05-06 08:36:53 +0200 |
| commit | 5f3b133a23c545272b6bc1e818a5a35e1ca84b1e (patch) | |
| tree | a3b8005fab8f8ce46facaabaf7c10dc41dfeedf4 /kernel | |
| parent | 433a76207dcf5facc0183acb790f6e8398585258 (diff) | |
dma-mapping: add a dma_need_unmap helper
Add helper that allows a driver to skip calling dma_unmap_*
if the DMA layer can guarantee that they are no-nops.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/dma/mapping.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index cda127027e48a..3c3204ad2839b 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -443,6 +443,24 @@ bool __dma_need_sync(struct device *dev, dma_addr_t dma_addr) } EXPORT_SYMBOL_GPL(__dma_need_sync); +/** + * dma_need_unmap - does this device need dma_unmap_* operations + * @dev: device to check + * + * If this function returns %false, drivers can skip calling dma_unmap_* after + * finishing an I/O. This function must be called after all mappings that might + * need to be unmapped have been performed. + */ +bool dma_need_unmap(struct device *dev) +{ + if (!dma_map_direct(dev, get_dma_ops(dev))) + return true; + if (!dev->dma_skip_sync) + return true; + return IS_ENABLED(CONFIG_DMA_API_DEBUG); +} +EXPORT_SYMBOL_GPL(dma_need_unmap); + static void dma_setup_need_sync(struct device *dev) { const struct dma_map_ops *ops = get_dma_ops(dev); |