From owner-svn-src-head@freebsd.org Mon May 7 18:11:23 2018 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 5A10AFB8822; Mon, 7 May 2018 18:11:23 +0000 (UTC) (envelope-from gallatin@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id A2CF88465B; Mon, 7 May 2018 18:11:22 +0000 (UTC) (envelope-from gallatin@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 9D9D71ECC2; Mon, 7 May 2018 18:11:22 +0000 (UTC) (envelope-from gallatin@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id w47IBM89026544; Mon, 7 May 2018 18:11:22 GMT (envelope-from gallatin@FreeBSD.org) Received: (from gallatin@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id w47IBMUx026543; Mon, 7 May 2018 18:11:22 GMT (envelope-from gallatin@FreeBSD.org) Message-Id: <201805071811.w47IBMUx026543@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: gallatin set sender to gallatin@FreeBSD.org using -f From: Andrew Gallatin Date: Mon, 7 May 2018 18:11:22 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r333329 - head/sys/net X-SVN-Group: head X-SVN-Commit-Author: gallatin X-SVN-Commit-Paths: head/sys/net X-SVN-Commit-Revision: 333329 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 07 May 2018 18:11:23 -0000 Author: gallatin Date: Mon May 7 18:11:22 2018 New Revision: 333329 URL: https://svnweb.freebsd.org/changeset/base/333329 Log: Fix an off-by-one error when deciding to request a tx interrupt The canonical check for whether or not a ring is drainable is TXQ_AVAIL() > MAX_TX_DESC() + 2. Use this same construct here, in order to avoid a potential off-by-one error where we might otherwise fail to request an interrupt. Reviewed by: mmacy Sponsored by: Netflix Modified: head/sys/net/iflib.c Modified: head/sys/net/iflib.c ============================================================================== --- head/sys/net/iflib.c Mon May 7 17:37:07 2018 (r333328) +++ head/sys/net/iflib.c Mon May 7 18:11:22 2018 (r333329) @@ -3299,7 +3299,7 @@ defrag: */ txq->ift_rs_pending += nsegs + 1; if (txq->ift_rs_pending > TXQ_MAX_RS_DEFERRED(txq) || - iflib_no_tx_batch || (TXQ_AVAIL(txq) - nsegs - 1) <= MAX_TX_DESC(ctx)) { + iflib_no_tx_batch || (TXQ_AVAIL(txq) - nsegs) <= MAX_TX_DESC(ctx) + 2) { pi.ipi_flags |= IPI_TX_INTR; txq->ift_rs_pending = 0; }