Date: Fri, 5 Aug 2016 08:57:51 +0000 (UTC) From: Sepherosa Ziehau <sephe@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r303764 - head/sys/dev/hyperv/vmbus Message-ID: <201608050857.u758vpRi074774@repo.freebsd.org>
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Author: sephe Date: Fri Aug 5 08:57:51 2016 New Revision: 303764 URL: https://svnweb.freebsd.org/changeset/base/303764 Log: hyperv/vmbus: Only make sure the TX bufring will not be closed. KVP can write data, whose size is > 1/2 TX bufring size. MFC after: 1 week Sponsored by: Microsoft OSTC Differential Revision: https://reviews.freebsd.org/D7414 Modified: head/sys/dev/hyperv/vmbus/vmbus_brvar.h Modified: head/sys/dev/hyperv/vmbus/vmbus_brvar.h ============================================================================== --- head/sys/dev/hyperv/vmbus/vmbus_brvar.h Fri Aug 5 06:23:06 2016 (r303763) +++ head/sys/dev/hyperv/vmbus/vmbus_brvar.h Fri Aug 5 08:57:51 2016 (r303764) @@ -74,8 +74,12 @@ struct sysctl_oid; static __inline int vmbus_txbr_maxpktsz(const struct vmbus_txbr *tbr) { - /* 1/2 data size */ - return (tbr->txbr_dsize / 2); + /* + * - 64 bits for the trailing start index (- sizeof(uint64_t)). + * - The rindex and windex can't be same (- 1). See + * the comment near vmbus_bufring.br_{r,w}index. + */ + return (tbr->txbr_dsize - sizeof(uint64_t) - 1); } void vmbus_br_sysctl_create(struct sysctl_ctx_list *ctx,
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