From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rusty Russell Subject: Re: [PATCHv7 2/4] virtio_console: Use kmalloc instead of kzalloc Date: Tue, 23 Oct 2012 12:06:34 +1030 Message-ID: <87d30ahsv1.fsf@rustcorp.com.au> References: <1350287856-5284-1-git-send-email-sjur.brandeland@stericsson.com> <1350287856-5284-3-git-send-email-sjur.brandeland@stericsson.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <1350287856-5284-3-git-send-email-sjur.brandeland@stericsson.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Amit Shah Cc: "Michael S. Tsirkin" , Linus Walleij , linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Masami Hiramatsu , Sjur =?utf-8?Q?Br=C3=A6ndeland?= List-Id: virtualization@lists.linuxfoundation.org c2p1ci5icmFuZGVsYW5kQHN0ZXJpY3Nzb24uY29tIHdyaXRlczoKCj4gRnJvbTogU2p1ciBCcsOm bmRlbGFuZCA8c2p1ci5icmFuZGVsYW5kQHN0ZXJpY3Nzb24uY29tPgo+Cj4gQXZvaWQgdGhlIG1v cmUgY3B1IGV4cGVuc2l2ZSBremFsbG9jIHdoZW4gYWxsb2NhdGluZyBidWZmZXJzLgo+IE9yaWdp bmFsbHkga3phbGxvYyB3YXMgaW50ZW5kZWQgZm9yIGlzb2xhdGluZyB0aGUgZ3Vlc3QgZnJvbQo+ IHRoZSBob3N0IGJ5IG5vdCBzZW5kaW5nIHJhbmRvbSBndWVzdCBkYXRhIHRvIHRoZSBob3N0LiBC dXQgZGV2aWNlCj4gaXNvbGF0aW9uIGlzIG5vdCB5ZXQgaW4gcGxhY2Ugc28ga3phbGxvYyBpcyBu b3QgcmVhbGx5IG5lZWRlZC4KPgo+IFNpZ25lZC1vZmYtYnk6IFNqdXIgQnLDpm5kZWxhbmQgPHNq dXIuYnJhbmRlbGFuZEBzdGVyaWNzc29uLmNvbT4KClRoaXMgbG9va3MgZmluZSB0byBtZS4gIFRo aXMgaXMgKndoeSogdGhlIGRldmljZSBnaXZlcyB1cyB0aGUgbGVuZ3RoCndoaWNoIHdhcyB3cml0 dGVuOyB3ZSBjYW4gdHJ1c3QgdGhhdCwgZXZlbiBpZiB3ZSBjYW4ndCB0cnVzdCB0aGUKd3JpdGVy IG9mIGRhdGEuCgooSW4gdGhlb3J5OiBub29uZSBoYXMgaW1wbGVtZW50ZWQgc3VjaCBhIHN5c3Rl bSwgeWV0KS4KCkFwcGxpZWQuClJ1c3R5LgoKPiBkaWZmIC0tZ2l0IGEvZHJpdmVycy9jaGFyL3Zp cnRpb19jb25zb2xlLmMgYi9kcml2ZXJzL2NoYXIvdmlydGlvX2NvbnNvbGUuYwo+IGluZGV4IGMz NmIyZjYuLjMwMWQxN2UgMTAwNjQ0Cj4gLS0tIGEvZHJpdmVycy9jaGFyL3ZpcnRpb19jb25zb2xl LmMKPiArKysgYi9kcml2ZXJzL2NoYXIvdmlydGlvX2NvbnNvbGUuYwo+IEBAIC0zNDksNyArMzQ5 LDcgQEAgc3RhdGljIHN0cnVjdCBwb3J0X2J1ZmZlciAqYWxsb2NfYnVmKHNpemVfdCBidWZfc2l6 ZSkKPiAgCWJ1ZiA9IGttYWxsb2Moc2l6ZW9mKCpidWYpLCBHRlBfS0VSTkVMKTsKPiAgCWlmICgh YnVmKQo+ICAJCWdvdG8gZmFpbDsKPiAtCWJ1Zi0+YnVmID0ga3phbGxvYyhidWZfc2l6ZSwgR0ZQ X0tFUk5FTCk7Cj4gKwlidWYtPmJ1ZiA9IGttYWxsb2MoYnVmX3NpemUsIEdGUF9LRVJORUwpOwo+ ICAJaWYgKCFidWYtPmJ1ZikKPiAgCQlnb3RvIGZyZWVfYnVmOwo+ICAJYnVmLT5sZW4gPSAwOwo+ IC0tIAo+IDEuNy41LjQKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX18KVmlydHVhbGl6YXRpb24gbWFpbGluZyBsaXN0ClZpcnR1YWxpemF0aW9uQGxpc3RzLmxp bnV4LWZvdW5kYXRpb24ub3JnCmh0dHBzOi8vbGlzdHMubGludXhmb3VuZGF0aW9uLm9yZy9tYWls bWFuL2xpc3RpbmZvL3ZpcnR1YWxpemF0aW9u From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756584Ab2JWCBB (ORCPT ); Mon, 22 Oct 2012 22:01:01 -0400 Received: from ozlabs.org ([203.10.76.45]:54504 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756496Ab2JWCA4 convert rfc822-to-8bit (ORCPT ); Mon, 22 Oct 2012 22:00:56 -0400 From: Rusty Russell To: sjur.brandeland@stericsson.com, Amit Shah Cc: "Michael S. Tsirkin" , Linus Walleij , Masami Hiramatsu , Ohad Ben-Cohen , linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, sjurbren@gmail.com, Sjur =?utf-8?Q?Br=C3=A6ndeland?= Subject: Re: [PATCHv7 2/4] virtio_console: Use kmalloc instead of kzalloc In-Reply-To: <1350287856-5284-3-git-send-email-sjur.brandeland@stericsson.com> References: <1350287856-5284-1-git-send-email-sjur.brandeland@stericsson.com> <1350287856-5284-3-git-send-email-sjur.brandeland@stericsson.com> User-Agent: Notmuch/0.14 (http://notmuchmail.org) Emacs/23.4.1 (i686-pc-linux-gnu) Date: Tue, 23 Oct 2012 12:06:34 +1030 Message-ID: <87d30ahsv1.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org sjur.brandeland@stericsson.com writes: > From: Sjur Brændeland > > Avoid the more cpu expensive kzalloc when allocating buffers. > Originally kzalloc was intended for isolating the guest from > the host by not sending random guest data to the host. But device > isolation is not yet in place so kzalloc is not really needed. > > Signed-off-by: Sjur Brændeland This looks fine to me. This is *why* the device gives us the length which was written; we can trust that, even if we can't trust the writer of data. (In theory: noone has implemented such a system, yet). Applied. Rusty. > diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c > index c36b2f6..301d17e 100644 > --- a/drivers/char/virtio_console.c > +++ b/drivers/char/virtio_console.c > @@ -349,7 +349,7 @@ static struct port_buffer *alloc_buf(size_t buf_size) > buf = kmalloc(sizeof(*buf), GFP_KERNEL); > if (!buf) > goto fail; > - buf->buf = kzalloc(buf_size, GFP_KERNEL); > + buf->buf = kmalloc(buf_size, GFP_KERNEL); > if (!buf->buf) > goto free_buf; > buf->len = 0; > -- > 1.7.5.4