Date: Mon, 11 Jan 2016 20:38:39 +0000 (UTC) From: Colin Percival <cperciva@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r293698 - head/sys/kern Message-ID: <201601112038.u0BKcdhW088420@repo.freebsd.org>
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Author: cperciva Date: Mon Jan 11 20:38:39 2016 New Revision: 293698 URL: https://svnweb.freebsd.org/changeset/base/293698 Log: Fix a bug introduced in r291716: "The problem with the approach taken both in _bus_dmamap_load_pages and bus_dmamap_load_ma_triv is that they split the request buffer into arbitrary chunks based on page boundaries, creating segments that no longer have a size that's a multiple of the sector size. This breaks drivers like blkfront (and probably other stuff)." [1] This was most easily triggered by running `fsck /` on a system running in Xen (e.g. Amazon EC2) but also showed up via growfs(8) and probably many other userland tools which access the disk directly. Patch by: royger [1] "Thinks this should be fine" by: ken Modified: head/sys/kern/subr_bus_dma.c Modified: head/sys/kern/subr_bus_dma.c ============================================================================== --- head/sys/kern/subr_bus_dma.c Mon Jan 11 20:27:05 2016 (r293697) +++ head/sys/kern/subr_bus_dma.c Mon Jan 11 20:38:39 2016 (r293698) @@ -131,28 +131,6 @@ _bus_dmamap_load_mbuf_sg(bus_dma_tag_t d } /* - * Load tlen data starting at offset within a region specified by a list of - * physical pages. - */ -static int -_bus_dmamap_load_pages(bus_dma_tag_t dmat, bus_dmamap_t map, - vm_page_t *pages, bus_size_t tlen, int offset, int *nsegs, int flags) -{ - vm_paddr_t paddr; - bus_size_t len; - int error, i; - - for (i = 0, error = 0; error == 0 && tlen > 0; i++, tlen -= len) { - len = min(PAGE_SIZE - offset, tlen); - paddr = VM_PAGE_TO_PHYS(pages[i]) + offset; - error = _bus_dmamap_load_phys(dmat, map, paddr, len, - flags, NULL, nsegs); - offset = 0; - } - return (error); -} - -/* * Load from block io. */ static int @@ -168,8 +146,8 @@ _bus_dmamap_load_bio(bus_dma_tag_t dmat, } if ((bio->bio_flags & BIO_UNMAPPED) != 0) - return (_bus_dmamap_load_pages(dmat, map, bio->bio_ma, - bio->bio_bcount, bio->bio_ma_offset, nsegs, flags)); + return (_bus_dmamap_load_ma(dmat, map, bio->bio_ma, + bio->bio_bcount, bio->bio_ma_offset, flags, NULL, nsegs)); return (_bus_dmamap_load_buffer(dmat, map, bio->bio_data, bio->bio_bcount, kernel_pmap, flags, NULL, nsegs));
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