Date: Mon, 18 May 2020 09:44:26 +0000 (UTC) From: Hans Petter Selasky <hselasky@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r361205 - stable/12/sys/compat/linuxkpi/common/include/linux Message-ID: <202005180944.04I9iQAq077329@repo.freebsd.org>
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Author: hselasky Date: Mon May 18 09:44:26 2020 New Revision: 361205 URL: https://svnweb.freebsd.org/changeset/base/361205 Log: MFC r360623: Optimise use of sg_page_count() in __sg_page_iter_next() in the LinuxKPI. No need to compute value twice. No functional change intended. Sponsored by: Mellanox Technologies Modified: stable/12/sys/compat/linuxkpi/common/include/linux/scatterlist.h Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/compat/linuxkpi/common/include/linux/scatterlist.h ============================================================================== --- stable/12/sys/compat/linuxkpi/common/include/linux/scatterlist.h Mon May 18 09:43:31 2020 (r361204) +++ stable/12/sys/compat/linuxkpi/common/include/linux/scatterlist.h Mon May 18 09:44:26 2020 (r361205) @@ -416,6 +416,8 @@ sg_page_count(struct scatterlist *sg) static inline bool __sg_page_iter_next(struct sg_page_iter *piter) { + unsigned int pgcount; + if (piter->internal.nents == 0) return (0); if (piter->sg == NULL) @@ -424,8 +426,11 @@ __sg_page_iter_next(struct sg_page_iter *piter) piter->sg_pgoffset += piter->internal.pg_advance; piter->internal.pg_advance = 1; - while (piter->sg_pgoffset >= sg_page_count(piter->sg)) { - piter->sg_pgoffset -= sg_page_count(piter->sg); + while (1) { + pgcount = sg_page_count(piter->sg); + if (likely(piter->sg_pgoffset < pgcount)) + break; + piter->sg_pgoffset -= pgcount; piter->sg = sg_next(piter->sg); if (--piter->internal.nents == 0) return (0);
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