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Mon, 21 Sep 2020 14:34:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=puJFCdMF2FXbv89uAHf/KkyLCkpGKdSCiHzE06eX0/Y=; b=GRkfTBxWaYN59mWczbVBJZ/J4z kVM8Nphlbf3FY02zkGWWBVM283NPs2K9y+IDVdwyxNN1Q6a4B7YoCyWtJodiottCcy6XpP96dRyGn JHkp6fow0Ism2aY5WYKFck/rP6z+BMXBmYaJqqKRA5DWZwKptXaUZhs1y+Gx9Hcs78ge5sNfRyKIN h2HYTgdyzISCw5GbBnBiQ0zAOMx4TZdmJQTPfx5COcVblaZe9D1Cqm0YVjyEpK04tgDaqtazmJ5UR ftg8Mk3Zj7g+8AAriBQApIZOIJYX0rTvWCnxH8RgTXNwePT8RLDRBDPDY+Cv19f1nEHzB8vcryJzp d7oTPRIQ==; Received: from p4fdb0c34.dip0.t-ipconnect.de ([79.219.12.52] helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kKMtZ-0007rC-EL; Mon, 21 Sep 2020 14:34:21 +0000 From: Christoph Hellwig To: Alexander Viro Cc: Andrew Morton , Jens Axboe , Arnd Bergmann , David Howells , David Laight , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, io-uring@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, David Laight , David Laight Subject: [PATCH 02/11] mm: call import_iovec() instead of rw_copy_check_uvector() in process_vm_rw() Date: Mon, 21 Sep 2020 16:34:25 +0200 Message-Id: <20200921143434.707844-3-hch@lst.de> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200921143434.707844-1-hch@lst.de> References: <20200921143434.707844-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: David Laight This is the only direct call of rw_copy_check_uvector(). Removing it will allow rw_copy_check_uvector() to be inlined into import_iovec(), while only paying a minor price by setting up an otherwise unused iov_iter in the process_vm_readv/process_vm_writev syscalls that aren't in a super hot path. Signed-off-by: David Laight [hch: expanded the commit log, pass CHECK_IOVEC_ONLY instead of 0 for the compat case, handle CHECK_IOVEC_ONLY in iov_iter_init] Signed-off-by: Christoph Hellwig --- lib/iov_iter.c | 2 +- mm/process_vm_access.c | 33 ++++++++++++++++++--------------- 2 files changed, 19 insertions(+), 16 deletions(-) diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 5e40786c8f1232..db54588406dfae 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -443,7 +443,7 @@ void iov_iter_init(struct iov_iter *i, unsigned int direction, const struct iovec *iov, unsigned long nr_segs, size_t count) { - WARN_ON(direction & ~(READ | WRITE)); + WARN_ON(direction & ~(READ | WRITE | CHECK_IOVEC_ONLY)); direction &= READ | WRITE; /* It will get better. Eventually... */ diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c index 29c052099affdc..40cd502c337534 100644 --- a/mm/process_vm_access.c +++ b/mm/process_vm_access.c @@ -264,7 +264,7 @@ static ssize_t process_vm_rw(pid_t pid, struct iovec iovstack_r[UIO_FASTIOV]; struct iovec *iov_l = iovstack_l; struct iovec *iov_r = iovstack_r; - struct iov_iter iter; + struct iov_iter iter_l, iter_r; ssize_t rc; int dir = vm_write ? WRITE : READ; @@ -272,23 +272,25 @@ static ssize_t process_vm_rw(pid_t pid, return -EINVAL; /* Check iovecs */ - rc = import_iovec(dir, lvec, liovcnt, UIO_FASTIOV, &iov_l, &iter); + rc = import_iovec(dir, lvec, liovcnt, UIO_FASTIOV, &iov_l, &iter_l); if (rc < 0) return rc; - if (!iov_iter_count(&iter)) + if (!iov_iter_count(&iter_l)) goto free_iovecs; - rc = rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt, UIO_FASTIOV, - iovstack_r, &iov_r); + rc = import_iovec(CHECK_IOVEC_ONLY, rvec, riovcnt, UIO_FASTIOV, &iov_r, + &iter_r); if (rc <= 0) goto free_iovecs; - rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write); + rc = process_vm_rw_core(pid, &iter_l, iter_r.iov, iter_r.nr_segs, + flags, vm_write); free_iovecs: if (iov_r != iovstack_r) kfree(iov_r); - kfree(iov_l); + if (iov_l != iovstack_l) + kfree(iov_l); return rc; } @@ -322,30 +324,31 @@ compat_process_vm_rw(compat_pid_t pid, struct iovec iovstack_r[UIO_FASTIOV]; struct iovec *iov_l = iovstack_l; struct iovec *iov_r = iovstack_r; - struct iov_iter iter; + struct iov_iter iter_l, iter_r; ssize_t rc = -EFAULT; int dir = vm_write ? WRITE : READ; if (flags != 0) return -EINVAL; - rc = compat_import_iovec(dir, lvec, liovcnt, UIO_FASTIOV, &iov_l, &iter); + rc = compat_import_iovec(dir, lvec, liovcnt, UIO_FASTIOV, &iov_l, &iter_l); if (rc < 0) return rc; - if (!iov_iter_count(&iter)) + if (!iov_iter_count(&iter_l)) goto free_iovecs; - rc = compat_rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt, - UIO_FASTIOV, iovstack_r, - &iov_r); + rc = compat_import_iovec(CHECK_IOVEC_ONLY, rvec, riovcnt, UIO_FASTIOV, + &iov_r, &iter_r); if (rc <= 0) goto free_iovecs; - rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write); + rc = process_vm_rw_core(pid, &iter_l, iter_r.iov, iter_r.nr_segs, + flags, vm_write); free_iovecs: if (iov_r != iovstack_r) kfree(iov_r); - kfree(iov_l); + if (iov_l != iovstack_l) + kfree(iov_l); return rc; }