path: root/block/blk-settings.c
diff options
authorAndrea Arcangeli <andrea@qumranet.com>2008-04-02 09:06:44 +0200
committerJens Axboe <jens.axboe@oracle.com>2008-04-02 09:06:44 +0200
commit00d61e3e8c12d5f395b167856d2b3c430816afb0 (patch)
tree757df09b076810b40ee3431a394882a2be860a68 /block/blk-settings.c
parent0e81a8ae37687845f7cdfa2adce14ea6a5f1dd34 (diff)
Fix bounce setting for 64-bit
Looking a bit closer into this regression the reason this can't be right is that dma_addr common default is BLK_BOUNCE_HIGH and most machines have less than 4G. So if you do: if (b_pfn <= (min_t(u64, 0xffffffff, BLK_BOUNCE_HIGH) >> PAGE_SHIFT)) dma = 1 that will translate to: if (BLK_BOUNCE_HIGH <= BLK_BOUNCE_HIGH) dma = 1 So for 99% of hardware this will trigger unnecessary GFP_DMA allocations and isa pooling operations. Also note how the 32bit code still does b_pfn < blk_max_low_pfn. I guess this is what you were looking after. I didn't verify but as far as I can tell, this will stop the regression with isa dma operations at boot for 99% of blkdev/memory combinations out there and I guess this fixes the setups with >4G of ram and 32bit pci cards as well (this also retains symmetry with the 32bit code). Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blk-settings.c')
1 files changed, 1 insertions, 1 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 1344a0ea5cc..5713f7e5cbd 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -140,7 +140,7 @@ void blk_queue_bounce_limit(struct request_queue *q, u64 dma_addr)
/* Assume anything <= 4GB can be handled by IOMMU.
Actually some IOMMUs can handle everything, but I don't
know of a way to test this here. */
- if (b_pfn <= (min_t(u64, 0xffffffff, BLK_BOUNCE_HIGH) >> PAGE_SHIFT))
+ if (b_pfn < (min_t(u64, 0x100000000UL, BLK_BOUNCE_HIGH) >> PAGE_SHIFT))
dma = 1;
q->bounce_pfn = max_low_pfn;