The following reply was made to PR kern/152818; it has been noted by GNATS.
From: dfil...@freebsd.org (dfilter service) To: bug-follo...@freebsd.org Cc: Subject: Re: kern/152818: commit references a PR Date: Sun, 5 Dec 2010 03:21:00 +0000 (UTC) Author: cperciva Date: Sun Dec 5 03:20:55 2010 New Revision: 216194 URL: http://svn.freebsd.org/changeset/base/216194 Log: MFamd64 r204214: Enforce stronger alignment semantics (require that the end of segments be aligned, not just the start of segments) in order to allow Xen's blkfront driver to operate correctly. PR: kern/152818 MFC after: 3 days Modified: head/sys/i386/i386/busdma_machdep.c Modified: head/sys/i386/i386/busdma_machdep.c ============================================================================== --- head/sys/i386/i386/busdma_machdep.c Sun Dec 5 01:17:53 2010 (r216193) +++ head/sys/i386/i386/busdma_machdep.c Sun Dec 5 03:20:55 2010 (r216194) @@ -246,8 +246,7 @@ 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; @@ -594,15 +593,19 @@ _bus_dmamap_count_pages(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 (((dmat->flags & BUS_DMA_COULD_BOUNCE) != 0) && 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); } @@ -669,6 +672,8 @@ _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. */ @@ -680,11 +685,16 @@ _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 (((dmat->flags & BUS_DMA_COULD_BOUNCE) != 0) && + 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. @@ -695,10 +705,6 @@ _bus_dmamap_load_buffer(bus_dma_tag_t dm sgsize = (baddr - curaddr); } - if (((dmat->flags & BUS_DMA_COULD_BOUNCE) != 0) && - 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. _______________________________________________ svn-src-...@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org" _______________________________________________ freebsd-xen@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-xen To unsubscribe, send any mail to "freebsd-xen-unsubscr...@freebsd.org"
