diff options
| author | FUJITA Tomonori <tomof@acm.org> | 2008-02-04 22:28:16 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2008-02-05 09:44:12 -0800 |
| commit | 681cc5cd3efbeafca6386114070e0bfb5012e249 (patch) | |
| tree | 21249148cf78175e1d099999784053a14dc2fc50 /lib/swiotlb.c | |
| parent | 59fc67dedb46c29442989e52af39da67aea52512 (diff) | |
| download | linux-681cc5cd3efbeafca6386114070e0bfb5012e249.tar.bz2 | |
iommu sg merging: swiotlb: respect the segment boundary limits
This patch makes swiotlb not allocate a memory area spanning LLD's segment
boundary.
is_span_boundary() judges whether a memory area spans LLD's segment boundary.
If map_single finds such a area, map_single tries to find the next available
memory area.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Greg KH <greg@kroah.com>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/swiotlb.c')
| -rw-r--r-- | lib/swiotlb.c | 41 |
1 files changed, 35 insertions, 6 deletions
diff --git a/lib/swiotlb.c b/lib/swiotlb.c index 1a8050ade861..4bb5a11e18a2 100644 --- a/lib/swiotlb.c +++ b/lib/swiotlb.c @@ -282,6 +282,15 @@ address_needs_mapping(struct device *hwdev, dma_addr_t addr) return (addr & ~mask) != 0; } +static inline unsigned int is_span_boundary(unsigned int index, + unsigned int nslots, + unsigned long offset_slots, + unsigned long max_slots) +{ + unsigned long offset = (offset_slots + index) & (max_slots - 1); + return offset + nslots > max_slots; +} + /* * Allocates bounce buffer and returns its kernel virtual address. */ @@ -292,6 +301,16 @@ map_single(struct device *hwdev, char *buffer, size_t size, int dir) char *dma_addr; unsigned int nslots, stride, index, wrap; int i; + unsigned long start_dma_addr; + unsigned long mask; + unsigned long offset_slots; + unsigned long max_slots; + + mask = dma_get_seg_boundary(hwdev); + start_dma_addr = virt_to_bus(io_tlb_start) & mask; + + offset_slots = ALIGN(start_dma_addr, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT; + max_slots = ALIGN(mask + 1, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT; /* * For mappings greater than a page, we limit the stride (and @@ -311,10 +330,17 @@ map_single(struct device *hwdev, char *buffer, size_t size, int dir) */ spin_lock_irqsave(&io_tlb_lock, flags); { - wrap = index = ALIGN(io_tlb_index, stride); - + index = ALIGN(io_tlb_index, stride); if (index >= io_tlb_nslabs) - wrap = index = 0; + index = 0; + + while (is_span_boundary(index, nslots, offset_slots, + max_slots)) { + index += stride; + if (index >= io_tlb_nslabs) + index = 0; + } + wrap = index; do { /* @@ -341,9 +367,12 @@ map_single(struct device *hwdev, char *buffer, size_t size, int dir) goto found; } - index += stride; - if (index >= io_tlb_nslabs) - index = 0; + do { + index += stride; + if (index >= io_tlb_nslabs) + index = 0; + } while (is_span_boundary(index, nslots, offset_slots, + max_slots)); } while (index != wrap); spin_unlock_irqrestore(&io_tlb_lock, flags); |