From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.223.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8500A182B7 for ; Mon, 22 Sep 2025 10:28:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.131 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758536936; cv=none; b=Pp4UVtn/UqvZymhrhJGGvyhcSzANxei031VsODSEMrlW3EaoWQA1T+X6fOSoj7u2tIQVRm5dYyO4id1vu32vlf3yaOQxa8Fi4kbujl/r50Qf4+fJtS9PBd5MbnlAMWFs3ag/IJxJ/Ml0NlVlfo+rrKS5/9mLuryXObiPLDLKlPM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758536936; c=relaxed/simple; bh=GKNbTJkYnR5VYhj9qSO1W/nnJGH7QggS3jfumZApEXc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=P8lh9iLYYJIAb3vNTT4tS5H1VP8/tyOogoewx3amQWLV1A8D0JxiFhtvev2C8An6E1L5m/LABx1QTjJ+smly3LIT//3c0xUKmYs7gBDfzoqeZDnEKC8Mlhl8d2PjK3yuW7OdpZEMN09VeoSwT1CcLnTwYfWWM3NCrqUCqZ4QY9M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz; spf=pass smtp.mailfrom=suse.cz; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b=G1AT08Mv; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b=JkBAPZiV; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b=h8OXeqvf; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b=9lI31nYW; arc=none smtp.client-ip=195.135.223.131 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.cz Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b="G1AT08Mv"; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b="JkBAPZiV"; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b="h8OXeqvf"; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b="9lI31nYW" Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [IPv6:2a07:de40:b281:104:10:150:64:97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id B05ED1FE59; Mon, 22 Sep 2025 10:28:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1758536932; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=GKNbTJkYnR5VYhj9qSO1W/nnJGH7QggS3jfumZApEXc=; b=G1AT08MvHIZWesCigcCrfn1iYSMPRrwrEbfQDBHzAEu+orb7sNt9CYB1F/GEhrkM2FRKV/ 3rsbiNeh0rDKwl6iBw99d8NOQH6EaTi3T0VSf6E1M6ZyQLmI9xWImOaI7kCRkhf6hr0Vza h4pDeo/JggfqRL7QZEeZS5VSQSpzQ7s= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1758536932; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=GKNbTJkYnR5VYhj9qSO1W/nnJGH7QggS3jfumZApEXc=; b=JkBAPZiVtq1fDHcBmdM193S36bjeHM6mIKg446mWmfHN6umRWq6zdY5G3DkHkej+eq/h8X eZdeUiPhFvxttrDg== Authentication-Results: smtp-out2.suse.de; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=h8OXeqvf; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=9lI31nYW DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1758536931; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=GKNbTJkYnR5VYhj9qSO1W/nnJGH7QggS3jfumZApEXc=; b=h8OXeqvfpgPKLiM19htaj+JvPW4+VXcv9A3uAPMOql/mjsHtVR85CPRFQPLwhylvwKu9nL qEhQtEyz3eXSVl+w2syd5ArUuavrhUNULorT3lLeDaKDqT5KIwl+nWF7bMA3PRSdhYq39g rv3XAzVdyjPFp8mYeXvfZ5QY5uhHknc= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1758536931; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=GKNbTJkYnR5VYhj9qSO1W/nnJGH7QggS3jfumZApEXc=; b=9lI31nYWubDQlZdRsUE66AaUhtCvCfpVO60odwbco67zJ4QgdbwuRr5r+LczM9hAtoiiQ7 IrVPh7C+nwlO1vBQ== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 9609913A63; Mon, 22 Sep 2025 10:28:51 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id cUR5JOMk0WhyPQAAD6G6ig (envelope-from ); Mon, 22 Sep 2025 10:28:51 +0000 Date: Mon, 22 Sep 2025 12:28:50 +0200 From: David Sterba To: Miquel =?iso-8859-1?Q?Sabat=E9_Sol=E0?= Cc: linux-btrfs@vger.kernel.org, clm@fb.com, dsterba@suse.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] btrfs: Prevent open-coded arithmetic in kmalloc Message-ID: <20250922102850.GL5333@twin.jikos.cz> Reply-To: dsterba@suse.cz References: <20250919145816.959845-1-mssola@mssola.com> <20250919145816.959845-2-mssola@mssola.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20250919145816.959845-2-mssola@mssola.com> User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) X-Spamd-Result: default: False [-4.21 / 50.00]; BAYES_HAM(-3.00)[99.99%]; NEURAL_HAM_LONG(-1.00)[-1.000]; HAS_REPLYTO(0.30)[dsterba@suse.cz]; R_DKIM_ALLOW(-0.20)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; RCVD_TLS_ALL(0.00)[]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; TO_DN_SOME(0.00)[]; MIME_TRACE(0.00)[0:+]; FUZZY_RATELIMITED(0.00)[rspamd.com]; REPLYTO_DOM_NEQ_TO_DOM(0.00)[]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; REPLYTO_ADDR_EQ_FROM(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; URIBL_BLOCKED(0.00)[suse.cz:replyto,suse.cz:dkim,suse.com:email,imap1.dmz-prg2.suse.org:helo,imap1.dmz-prg2.suse.org:rdns,twin.jikos.cz:mid,mssola.com:email]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.com:email,suse.cz:replyto,suse.cz:dkim]; RCPT_COUNT_FIVE(0.00)[5]; DKIM_TRACE(0.00)[suse.cz:+] X-Spam-Flag: NO X-Spam-Level: X-Rspamd-Queue-Id: B05ED1FE59 X-Rspamd-Server: rspamd2.dmz-prg2.suse.org X-Rspamd-Action: no action X-Spam-Score: -4.21 On Fri, Sep 19, 2025 at 04:58:15PM +0200, Miquel Sabaté Solà wrote: > As pointed out in the documentation, calling 'kmalloc' with open-coded > arithmetic can lead to unfortunate overflows and this particular way of > using it has been deprecated. Instead, it's preferred to use > 'kmalloc_array' in cases where it might apply so an overflow check is > performed. So this is an API cleanup and it makes sense to use the checked multiplication but it should be also said that this is not fixing any overflow because in all cases the multipliers are bounded small numbers derived from number of items in leaves/nodes. > Signed-off-by: Miquel Sabaté Solà Reviewed-by: David Sterba