Date: Tue, 6 Feb 2018 06:55:55 +0000 (UTC) From: Scott Long <scottl@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r328919 - head/sys/dev/mps Message-ID: <201802060655.w166ttPw076105@repo.freebsd.org>
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Author: scottl Date: Tue Feb 6 06:55:55 2018 New Revision: 328919 URL: https://svnweb.freebsd.org/changeset/base/328919 Log: Fix a case where a request frame can be composed that requires 2 or more SGList elements, but there's only enough space in the request frame for either 1 element or a chain frame pointer. Previously, the code would hit the wrong case, add the SGList element, but then fail to add the chain frame due to lack of space. Re-arrange the code to catch this case earlier and handle it. Sponsored by: Netflix Modified: head/sys/dev/mps/mps.c Modified: head/sys/dev/mps/mps.c ============================================================================== --- head/sys/dev/mps/mps.c Tue Feb 6 06:42:25 2018 (r328918) +++ head/sys/dev/mps/mps.c Tue Feb 6 06:55:55 2018 (r328919) @@ -2609,6 +2609,17 @@ mps_push_sge(struct mps_command *cm, void *sgep, size_ if (cm->cm_sglsize < MPS_SGC_SIZE) panic("MPS: Need SGE Error Code\n"); + if (segsleft >= 1 && cm->cm_sglsize < len + MPS_SGC_SIZE) { + /* + * 1 or more segment, enough room for only a chain. + * Hope the previous element wasn't a Simple entry + * that needed to be marked with + * MPI2_SGE_FLAGS_LAST_ELEMENT. Case (4). + */ + if ((error = mps_add_chain(cm)) != 0) + return (error); + } + if (segsleft >= 2 && cm->cm_sglsize < len + MPS_SGC_SIZE + MPS_SGE64_SIZE) { /* @@ -2631,17 +2642,6 @@ mps_push_sge(struct mps_command *cm, void *sgep, size_ bcopy(sgep, cm->cm_sge, len); cm->cm_sge = (MPI2_SGE_IO_UNION *)((uintptr_t)cm->cm_sge + len); return (mps_add_chain(cm)); - } - - if (segsleft >= 1 && cm->cm_sglsize < len + MPS_SGC_SIZE) { - /* - * 1 or more segment, enough room for only a chain. - * Hope the previous element wasn't a Simple entry - * that needed to be marked with - * MPI2_SGE_FLAGS_LAST_ELEMENT. Case (4). - */ - if ((error = mps_add_chain(cm)) != 0) - return (error); } #ifdef INVARIANTS
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