diff options
| author | Chao Gao <chao.gao@intel.com> | 2022-07-15 18:45:35 +0800 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2022-07-18 06:50:01 +0200 |
| commit | 57e6840cf79a4af84f44af3f8cfeacd8a14a6c6f (patch) | |
| tree | 066c3e6401fa68816347a4c109db5b94d729af56 /kernel/dma | |
| parent | 44335487bab05e06902f9184179857aae764bfe6 (diff) | |
| download | linux-57e6840cf79a4af84f44af3f8cfeacd8a14a6c6f.tar.gz | |
swiotlb: ensure a segment doesn't cross the area boundary
Free slots tracking assumes that slots in a segment can be allocated to
fulfill a request. This implies that slots in a segment should belong to
the same area. Although the possibility of a violation is low, it is better
to explicitly enforce segments won't span multiple areas by adjusting the
number of slabs when configuring areas.
Signed-off-by: Chao Gao <chao.gao@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'kernel/dma')
| -rw-r--r-- | kernel/dma/swiotlb.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 604f2469ac0e7..608923e8dab1d 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -91,12 +91,21 @@ struct io_tlb_area { /* * Round up number of slabs to the next power of 2. The last area is going * be smaller than the rest if default_nslabs is not power of two. + * The number of slot in an area should be a multiple of IO_TLB_SEGSIZE, + * otherwise a segment may span two or more areas. It conflicts with free + * contiguous slots tracking: free slots are treated contiguous no matter + * whether they cross an area boundary. * * Return true if default_nslabs is rounded up. */ static bool round_up_default_nslabs(void) { - if (!default_nareas || is_power_of_2(default_nslabs)) + if (!default_nareas) + return false; + + if (default_nslabs < IO_TLB_SEGSIZE * default_nareas) + default_nslabs = IO_TLB_SEGSIZE * default_nareas; + else if (is_power_of_2(default_nslabs)) return false; default_nslabs = roundup_pow_of_two(default_nslabs); return true; |