svn commit: r206610 - stable/8/sys/amd64/amd64
Justin T. Gibbs
gibbs at FreeBSD.org
Wed Apr 14 17:01:30 UTC 2010
Author: gibbs
Date: Wed Apr 14 17:01:29 2010
New Revision: 206610
URL: http://svn.freebsd.org/changeset/base/206610
Log:
MFC 204214:
Enforce stronger bus-dma alignment semantics so bus-dma operates correctly
with Xen's blkfront driver.
Modified:
stable/8/sys/amd64/amd64/busdma_machdep.c
Modified: stable/8/sys/amd64/amd64/busdma_machdep.c
==============================================================================
--- stable/8/sys/amd64/amd64/busdma_machdep.c Wed Apr 14 16:54:49 2010 (r206609)
+++ stable/8/sys/amd64/amd64/busdma_machdep.c Wed Apr 14 17:01:29 2010 (r206610)
@@ -239,8 +239,7 @@ bus_dma_tag_create(bus_dma_tag_t parent,
newtag->alignment = alignment;
newtag->boundary = boundary;
newtag->lowaddr = trunc_page((vm_paddr_t)lowaddr) + (PAGE_SIZE - 1);
- newtag->highaddr = trunc_page((vm_paddr_t)highaddr) +
- (PAGE_SIZE - 1);
+ newtag->highaddr = trunc_page((vm_paddr_t)highaddr) + (PAGE_SIZE - 1);
newtag->filter = filter;
newtag->filterarg = filterarg;
newtag->maxsize = maxsize;
@@ -605,13 +604,18 @@ _bus_dmamap_load_buffer(bus_dma_tag_t dm
vendaddr = (vm_offset_t)buf + buflen;
while (vaddr < vendaddr) {
+ bus_size_t sg_len;
+
+ sg_len = PAGE_SIZE - ((vm_offset_t)vaddr & PAGE_MASK);
if (pmap)
paddr = pmap_extract(pmap, vaddr);
else
paddr = pmap_kextract(vaddr);
- if (run_filter(dmat, paddr) != 0)
+ if (run_filter(dmat, paddr) != 0) {
+ sg_len = roundup2(sg_len, dmat->alignment);
map->pagesneeded++;
- vaddr += (PAGE_SIZE - ((vm_offset_t)vaddr & PAGE_MASK));
+ }
+ vaddr += sg_len;
}
CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
}
@@ -644,6 +648,8 @@ _bus_dmamap_load_buffer(bus_dma_tag_t dm
bmask = ~(dmat->boundary - 1);
for (seg = *segp; buflen > 0 ; ) {
+ bus_size_t max_sgsize;
+
/*
* Get the physical address for this segment.
*/
@@ -655,11 +661,15 @@ _bus_dmamap_load_buffer(bus_dma_tag_t dm
/*
* Compute the segment size, and adjust counts.
*/
- sgsize = PAGE_SIZE - ((u_long)curaddr & PAGE_MASK);
- if (sgsize > dmat->maxsegsz)
- sgsize = dmat->maxsegsz;
- if (buflen < sgsize)
- sgsize = buflen;
+ max_sgsize = MIN(buflen, dmat->maxsegsz);
+ sgsize = PAGE_SIZE - ((vm_offset_t)curaddr & PAGE_MASK);
+ if (map->pagesneeded != 0 && run_filter(dmat, curaddr)) {
+ sgsize = roundup2(sgsize, dmat->alignment);
+ sgsize = MIN(sgsize, max_sgsize);
+ curaddr = add_bounce_page(dmat, map, vaddr, sgsize);
+ } else {
+ sgsize = MIN(sgsize, max_sgsize);
+ }
/*
* Make sure we don't cross any boundaries.
@@ -670,9 +680,6 @@ _bus_dmamap_load_buffer(bus_dma_tag_t dm
sgsize = (baddr - curaddr);
}
- if (map->pagesneeded != 0 && run_filter(dmat, curaddr))
- curaddr = add_bounce_page(dmat, map, vaddr, sgsize);
-
/*
* Insert chunk into a segment, coalescing with
* previous segment if possible.
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