Date: Mon, 5 Dec 2016 23:46:21 +0000 (UTC) From: John Baldwin <jhb@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r309579 - in stable: 10/sys/dev/cxgbe 11/sys/dev/cxgbe Message-ID: <201612052346.uB5NkLEV054556@repo.freebsd.org>
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Author: jhb Date: Mon Dec 5 23:46:21 2016 New Revision: 309579 URL: https://svnweb.freebsd.org/changeset/base/309579 Log: MFC 307876: cxgbe(4): Fix bug in the calculation of the number of physically contiguous regions in an mbuf chain. If the payload of an mbuf ends at a page boundary count_mbuf_nsegs would incorrectly consider the next mbuf's payload physically contiguous based solely on a KVA comparison. Modified: stable/11/sys/dev/cxgbe/t4_sge.c Directory Properties: stable/11/ (props changed) Changes in other areas also in this revision: Modified: stable/10/sys/dev/cxgbe/t4_sge.c Directory Properties: stable/10/ (props changed) Modified: stable/11/sys/dev/cxgbe/t4_sge.c ============================================================================== --- stable/11/sys/dev/cxgbe/t4_sge.c Mon Dec 5 23:35:37 2016 (r309578) +++ stable/11/sys/dev/cxgbe/t4_sge.c Mon Dec 5 23:46:21 2016 (r309579) @@ -2101,24 +2101,6 @@ m_advance(struct mbuf **pm, int *poffset return ((void *)p); } -static inline int -same_paddr(char *a, char *b) -{ - - if (a == b) - return (1); - else if (a != NULL && b != NULL) { - vm_offset_t x = (vm_offset_t)a; - vm_offset_t y = (vm_offset_t)b; - - if ((x & PAGE_MASK) == (y & PAGE_MASK) && - pmap_kextract(x) == pmap_kextract(y)) - return (1); - } - - return (0); -} - /* * Can deal with empty mbufs in the chain that have m_len = 0, but the chain * must have at least one mbuf that's not empty. @@ -2126,24 +2108,25 @@ same_paddr(char *a, char *b) static inline int count_mbuf_nsegs(struct mbuf *m) { - char *prev_end, *start; + vm_paddr_t lastb, next; + vm_offset_t va; int len, nsegs; MPASS(m != NULL); nsegs = 0; - prev_end = NULL; + lastb = 0; for (; m; m = m->m_next) { len = m->m_len; if (__predict_false(len == 0)) continue; - start = mtod(m, char *); - - nsegs += sglist_count(start, len); - if (same_paddr(prev_end, start)) + va = mtod(m, vm_offset_t); + next = pmap_kextract(va); + nsegs += sglist_count(m->m_data, len); + if (lastb + 1 == next) nsegs--; - prev_end = start + len; + lastb = pmap_kextract(va + len - 1); } MPASS(nsegs > 0);
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