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 2194A1C283 for ; Mon, 23 Oct 2023 15:23:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="VcPcblnd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8F283C43395; Mon, 23 Oct 2023 15:23:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1698074629; bh=DKDkRNSnXzhTGGNSSBp7bEj76rJrv16ueNO8snSn1xE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VcPcblndPjltM3kPpB1dNBMKkG9OmDe6DBKHwdmhUxw+v48xPWdvpgtWSQNFuYnSm 8Kh538Lhp/sYcbvyk68w9U60ksCl3X7SnA479k58jOkT0AVyt6U109EBu3eIj8Ea7C KLaINIVpvxZ5BqjZB5DiKvU1nyaVMgm63PzpLffv3cO24wKpxogOQoJXi1aK79NJIH tFO8hVaKU7qjBYSf3CWybMEAjXNSYTQLc9SPWG9rEjmS5lgYv+BqYJ2wfWnl01T0HB tvSDGWkWSeBG5mEz2c+05C1Z+gGWPNQ+GIXnZ+3tvrTjiCuswtqi4+43SqJna3IYCm Er5MnJkiJPAww== From: Jakub Kicinski To: davem@davemloft.net Cc: netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, johannes.berg@intel.com, mpe@ellerman.id.au, j@w1.fi, jiri@resnulli.us Subject: [PATCH net-next v2 4/6] net: trust the bitmap in __dev_alloc_name() Date: Mon, 23 Oct 2023 08:23:44 -0700 Message-ID: <20231023152346.3639749-5-kuba@kernel.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20231023152346.3639749-1-kuba@kernel.org> References: <20231023152346.3639749-1-kuba@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Prior to restructuring __dev_alloc_name() handled both printf and non-printf names. In a clever attempt at code reuse it always prints the name into a buffer and checks if it's a duplicate. Trust the bitmap, and return an error if its full. This shrinks the possible ID space by one from 32K to 32K - 1, as previously the max value would have been tried as a valid ID. It seems very unlikely that anyone would care as we heard no requests to increase the max beyond 32k. Signed-off-by: Jakub Kicinski --- v2: - mention the loss of 1 entry in the commit message --- net/core/dev.c | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index bbfb02b4a228..d2698b4bbad4 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1119,18 +1119,11 @@ static int __dev_alloc_name(struct net *net, const char *name, char *res) i = find_first_zero_bit(inuse, max_netdevices); bitmap_free(inuse); + if (i == max_netdevices) + return -ENFILE; - snprintf(buf, IFNAMSIZ, name, i); - if (!netdev_name_in_use(net, buf)) { - strscpy(res, buf, IFNAMSIZ); - return i; - } - - /* It is possible to run out of possible slots - * when the name is long and there isn't enough space left - * for the digits, or if all bits are used. - */ - return -ENFILE; + snprintf(res, IFNAMSIZ, name, i); + return i; } /* Returns negative errno or allocated unit id (see __dev_alloc_name()) */ -- 2.41.0