From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 872DB25394C for ; Tue, 5 Aug 2025 18:44:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754419471; cv=none; b=g7TfkSkn4ui8x2OE4NCsVo0/XI11XUslTS/Kj6q7YH728yOwTTrai3YfsEe2M6Qee8hGwNLytU734MWYxad0Aj1d9988Kntc4KuBUHfaWTZkk1yGsbRor9TKht0HZAejXErs/Yg0gtEGgIon5VBHi4GjW9x/K3As/IR+ahtQv0U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754419471; c=relaxed/simple; bh=Phetx1Z0yj6+Gkn9ZxDbDyywbvLSkhkFuvJZYSc2wiQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=d656Oj03kdk81mPlOJn5X0vtnQRFdxVtsPD+RyLuGFhQnnQ0z5KN4m13CDvLAP4GKH2IsuJe7c/Ag5XRZYNPmSg0vQEv8Fb36oMaWOgsFalvUtN8cI60HW987/nMmcsx/UrF8ysWLNgIMmdeQDlh1V2VAv0EoaFL8wBFKjnwA1g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZByf8shJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZByf8shJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C4401C4CEF0; Tue, 5 Aug 2025 18:44:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754419471; bh=Phetx1Z0yj6+Gkn9ZxDbDyywbvLSkhkFuvJZYSc2wiQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZByf8shJmE/gcYYoDeKJzLUfiWxeeuehL80ZP8wy77Qhz6jxm5tmyXbNtUmb1jeoH KSvTCdw5ml57LVu49YkoKPiEjSvbqGqWcXFyjkFIsOkuQY3vSjJwaZl149fmVQz16W 3OYw2xh67frni9x3nqwk4AcIl3qJR7HLupjvvQV01ezb2gKM5gb070SNymqd9Zdgxp QavUyGOKN3WGXLYYDbRtFOwF1HO+fano9OWkgH1AyXyd9C8DBFwjb0wwuvPKhW/SNp E++SZbHVuOCcZPmp8oy69E5fYfGSnMyNn78pD5VapO4npFIKGPQvV5JDqD4D2AvDYy kRuZ3D6BvU6CA== From: Mike Snitzer To: Chuck Lever , Jeff Layton Cc: linux-nfs@vger.kernel.org Subject: [PATCH v4 1/4] NFSD: avoid using iov_iter_is_aligned() in nfsd_iter_read() Date: Tue, 5 Aug 2025 14:44:25 -0400 Message-ID: <20250805184428.5848-2-snitzer@kernel.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20250805184428.5848-1-snitzer@kernel.org> References: <20250805184428.5848-1-snitzer@kernel.org> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Mike Snitzer Check the bvec is DIO-aligned while creating it, saves CPU cycles by avoiding iterating the bvec elements a second time using iov_iter_is_aligned(). This prepares for Keith Busch's near-term removal of the iov_iter_is_aligned() interface. This fixes cel/nfsd-testing commit 5d78ac1e674b4 ("NFSD: issue READs using O_DIRECT even if IO is misaligned") and it should be folded into that commit so that NFSD doesn't require iov_iter_is_aligned() while it is being removed upstream in parallel. Fixes: cel/nfsd-testing 5d78ac1e674b4 ("NFSD: issue READs using O_DIRECT even if IO is misaligned") Signed-off-by: Mike Snitzer --- fs/nfsd/vfs.c | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-) diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 46189020172fb..e1751d3715264 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1226,7 +1226,10 @@ __be32 nfsd_iter_read(struct svc_rqst *rqstp, struct svc_fh *fhp, */ offset = read_dio.start; in_count = read_dio.end - offset; - kiocb.ki_flags = IOCB_DIRECT; + /* Verify ondisk DIO alignment, memory addrs checked below */ + if (likely(((offset | in_count) & + (nf->nf_dio_read_offset_align - 1)) == 0)) + kiocb.ki_flags = IOCB_DIRECT; } } else if (nfsd_io_cache_read == NFSD_IO_DONTCACHE) kiocb.ki_flags = IOCB_DONTCACHE; @@ -1236,16 +1239,24 @@ __be32 nfsd_iter_read(struct svc_rqst *rqstp, struct svc_fh *fhp, v = 0; total = in_count; if (read_dio.start_extra) { - bvec_set_page(&rqstp->rq_bvec[v++], read_dio.start_extra_page, + bvec_set_page(&rqstp->rq_bvec[v], read_dio.start_extra_page, read_dio.start_extra, PAGE_SIZE - read_dio.start_extra); + if (unlikely((kiocb.ki_flags & IOCB_DIRECT) && + rqstp->rq_bvec[v].bv_offset & (nf->nf_dio_mem_align - 1))) + kiocb.ki_flags &= ~IOCB_DIRECT; total -= read_dio.start_extra; + v++; } while (total) { len = min_t(size_t, total, PAGE_SIZE - base); - bvec_set_page(&rqstp->rq_bvec[v++], *(rqstp->rq_next_page++), - len, base); + bvec_set_page(&rqstp->rq_bvec[v], *(rqstp->rq_next_page++), len, base); + /* No need to verify memory is DIO-aligned since bv_offset is 0 */ + if (unlikely((kiocb.ki_flags & IOCB_DIRECT) && base && + (base & (nf->nf_dio_mem_align - 1)))) + kiocb.ki_flags &= ~IOCB_DIRECT; total -= len; base = 0; + v++; } if (WARN_ONCE(v > rqstp->rq_maxpages, "%s: v=%lu exceeds rqstp->rq_maxpages=%lu\n", __func__, @@ -1256,16 +1267,6 @@ __be32 nfsd_iter_read(struct svc_rqst *rqstp, struct svc_fh *fhp, if (!host_err) { trace_nfsd_read_vector(rqstp, fhp, offset, in_count); iov_iter_bvec(&iter, ITER_DEST, rqstp->rq_bvec, v, in_count); - - /* Double check nfsd_analyze_read_dio's DIO-aligned result */ - if (unlikely((kiocb.ki_flags & IOCB_DIRECT) && - !iov_iter_is_aligned(&iter, - nf->nf_dio_mem_align - 1, - nf->nf_dio_read_offset_align - 1))) { - /* Fallback to buffered IO */ - kiocb.ki_flags &= ~IOCB_DIRECT; - } - host_err = vfs_iocb_iter_read(file, &kiocb, &iter); } -- 2.44.0