diff options
| author | Michael S. Tsirkin <mst@redhat.com> | 2025-12-29 07:28:43 -0500 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2025-12-31 19:30:02 -0500 |
| commit | 61868dc55a119a5e4b912d458fc2c48ba80a35fe (patch) | |
| tree | 890eda524fdc6fd1609d056f201af91554b2dd02 /kernel | |
| parent | 1e8b5d855525e0863198797a67a69774f426e142 (diff) | |
dma-mapping: add DMA_ATTR_CPU_CACHE_CLEAN
When multiple small DMA_FROM_DEVICE or DMA_BIDIRECTIONAL buffers share a
cacheline, and DMA_API_DEBUG is enabled, we get this warning:
cacheline tracking EEXIST, overlapping mappings aren't supported.
This is because when one of the mappings is removed, while another one
is active, CPU might write into the buffer.
Add an attribute for the driver to promise not to do this, making the
overlapping safe, and suppressing the warning.
Message-ID: <2d5d091f9d84b68ea96abd545b365dd1d00bbf48.1767601130.git.mst@redhat.com>
Reviewed-by: Petr Tesarik <ptesarik@suse.com>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/dma/debug.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c index 138ede653de4..7e66d863d573 100644 --- a/kernel/dma/debug.c +++ b/kernel/dma/debug.c @@ -595,7 +595,8 @@ static void add_dma_entry(struct dma_debug_entry *entry, unsigned long attrs) if (rc == -ENOMEM) { pr_err_once("cacheline tracking ENOMEM, dma-debug disabled\n"); global_disable = true; - } else if (rc == -EEXIST && !(attrs & DMA_ATTR_SKIP_CPU_SYNC) && + } else if (rc == -EEXIST && + !(attrs & (DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_CPU_CACHE_CLEAN)) && !(IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC) && is_swiotlb_active(entry->dev))) { err_printk(entry->dev, entry, |