diff options
| author | Dan Williams <dan.j.williams@intel.com> | 2014-01-21 15:48:12 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-01-21 16:19:41 -0800 |
| commit | 0abdd7a81b7e3fd781d7fabcca49501852bba17e (patch) | |
| tree | 20ab3aa4b476ceaf6d3a824c842cd581445ded8b /include/linux/dma-debug.h | |
| parent | 03d11a0e458d7008192585124e4c3313c2829046 (diff) | |
dma-debug: introduce debug_dma_assert_idle()
Record actively mapped pages and provide an api for asserting a given
page is dma inactive before execution proceeds. Placing
debug_dma_assert_idle() in cow_user_page() flagged the violation of the
dma-api in the NET_DMA implementation (see commit 77873803363c "net_dma:
mark broken").
The implementation includes the capability to count, in a limited way,
repeat mappings of the same page that occur without an intervening
unmap. This 'overlap' counter is limited to the few bits of tag space
in a radix tree. This mechanism is added to mitigate false negative
cases where, for example, a page is dma mapped twice and
debug_dma_assert_idle() is called after the page is un-mapped once.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/dma-debug.h')
| -rw-r--r-- | include/linux/dma-debug.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/dma-debug.h b/include/linux/dma-debug.h index fc0e34ce038f..fe8cb610deac 100644 --- a/include/linux/dma-debug.h +++ b/include/linux/dma-debug.h @@ -85,6 +85,8 @@ extern void debug_dma_sync_sg_for_device(struct device *dev, extern void debug_dma_dump_mappings(struct device *dev); +extern void debug_dma_assert_idle(struct page *page); + #else /* CONFIG_DMA_API_DEBUG */ static inline void dma_debug_add_bus(struct bus_type *bus) @@ -183,6 +185,10 @@ static inline void debug_dma_dump_mappings(struct device *dev) { } +static inline void debug_dma_assert_idle(struct page *page) +{ +} + #endif /* CONFIG_DMA_API_DEBUG */ #endif /* __DMA_DEBUG_H */ |