From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) (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 AB90A13AA2B; Thu, 5 Sep 2024 10:10:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.130 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725531019; cv=none; b=gchQ6OqNzbzKcN72HnCRhNukWETRRW64HfXFR/STjl3GJkT7MxXZYytI5MeVm6j60A4goa2HtRegkoiS+pKXMzGLcpJj49TTOFwcXY5g563xQas3uwI9T5KcVLTSkbO3qg+pNI1fHOAgXD5rTWa8D+CbFhwwQx8uI0pQrff939Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725531019; c=relaxed/simple; bh=4OvP9ljVjWEhn0hF3oHwV51qlhoZH2nXlCSTpCQvfP8=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References: MIME-Version:Content-Type; b=f4RIMhLWSUuffbKUYZXP1AJB0DuLKScWnaBCvBT8Aa9nVHOClUvZnkh6OLr5LGiHple29cwQvGOL7VcdCBx+bQ5oedgR+Wsz6+FpVBiDLOR2Y6wxlWK0ximbrXitIwT5XYcMTWVBkXwzQfZYNIpPcTZ4POiro7nzrjUp15ND7uc= 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=ZH+wBdk6; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b=MmmFmWlt; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b=ZH+wBdk6; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b=MmmFmWlt; arc=none smtp.client-ip=195.135.223.130 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="ZH+wBdk6"; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b="MmmFmWlt"; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b="ZH+wBdk6"; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b="MmmFmWlt" Received: from pobox.suse.cz (unknown [10.100.2.14]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id E01EC21961; Thu, 5 Sep 2024 10:10:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1725531014; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=nJTfIzYXnlllHqZjh7Vi0R+mu/mG6WoXv37+SM86wZM=; b=ZH+wBdk6fOD09EtSIqtGNfl/gUpaiEaLp0JZFBiWGPtDE80wFwlo2UBMGRPd10OsqO/Qyx uGEi0AknGsHFxpPx1BTuoHQshUJY5vMoxGuCSisk16f2Sga43YIT32mluOhKAf1MW++s2T rfj4V04TNxQAfQKlrrDgn51Sg35RgTU= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1725531014; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=nJTfIzYXnlllHqZjh7Vi0R+mu/mG6WoXv37+SM86wZM=; b=MmmFmWltcKnPwephrKXGuNV32b9lB902gELSKrtpHQJmwmnoeGgio8l8i70t4ivw2pnbLf fDdvY2im7MLr6oDQ== Authentication-Results: smtp-out1.suse.de; none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1725531014; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=nJTfIzYXnlllHqZjh7Vi0R+mu/mG6WoXv37+SM86wZM=; b=ZH+wBdk6fOD09EtSIqtGNfl/gUpaiEaLp0JZFBiWGPtDE80wFwlo2UBMGRPd10OsqO/Qyx uGEi0AknGsHFxpPx1BTuoHQshUJY5vMoxGuCSisk16f2Sga43YIT32mluOhKAf1MW++s2T rfj4V04TNxQAfQKlrrDgn51Sg35RgTU= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1725531014; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=nJTfIzYXnlllHqZjh7Vi0R+mu/mG6WoXv37+SM86wZM=; b=MmmFmWltcKnPwephrKXGuNV32b9lB902gELSKrtpHQJmwmnoeGgio8l8i70t4ivw2pnbLf fDdvY2im7MLr6oDQ== Date: Thu, 5 Sep 2024 12:10:14 +0200 (CEST) From: Miroslav Benes To: Wardenjohn cc: jpoimboe@kernel.org, jikos@kernel.org, pmladek@suse.com, joe.lawrence@redhat.com, live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 1/2] Introduce klp_ops into klp_func structure In-Reply-To: <20240828022350.71456-2-zhangwarden@gmail.com> Message-ID: References: <20240828022350.71456-1-zhangwarden@gmail.com> <20240828022350.71456-2-zhangwarden@gmail.com> User-Agent: Alpine 2.21 (LSU 202 2017-01-01) 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=US-ASCII X-Spam-Score: -4.30 X-Spamd-Result: default: False [-4.30 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-0.999]; NEURAL_HAM_SHORT(-0.20)[-0.999]; MIME_GOOD(-0.10)[text/plain]; RCPT_COUNT_SEVEN(0.00)[7]; FREEMAIL_TO(0.00)[gmail.com]; MIME_TRACE(0.00)[0:+]; RCVD_COUNT_ZERO(0.00)[0]; ARC_NA(0.00)[]; MID_RHS_MATCH_FROMTLD(0.00)[]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; FUZZY_BLOCKED(0.00)[rspamd.com]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.com:email] X-Spam-Flag: NO X-Spam-Level: Hi, the subject is missing "livepatch: " prefix and I would prefer something like "livepatch: Move struct klp_ops to struct klp_func" On Wed, 28 Aug 2024, Wardenjohn wrote: > Before introduce feature "using". Klp transition will need an > easier way to get klp_ops from klp_func. I think that the patch might make sense on its own as a cleanup/optimization as Petr suggested. If fixed. See below. Then the changelog can be restructured and the above can be removed. Btw if it comes to it, I would much rather have something like "active" instead of "using". > This patch make changes as follows: > 1. Move klp_ops into klp_func structure. > Rewrite the logic of klp_find_ops and > other logic to get klp_ops of a function. > > 2. Move definition of struct klp_ops into > include/linux/livepatch.h > > With this changes, we can get klp_ops of a klp_func easily. > klp_find_ops can also be simple and straightforward. And we > do not need to maintain one global list for now. > > Signed-off-by: Wardenjohn Missing "Suggested-by: Petr Mladek perhaps? >diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h >index 51a258c24ff5..d874aecc817b 100644 >--- a/include/linux/livepatch.h >+++ b/include/linux/livepatch.h >@@ -22,6 +22,25 @@ > #define KLP_TRANSITION_UNPATCHED 0 > #define KLP_TRANSITION_PATCHED 1 > >+/** >+ * struct klp_ops - structure for tracking registered ftrace ops structs >+ * >+ * A single ftrace_ops is shared between all enabled replacement functions >+ * (klp_func structs) which have the same old_func. This allows the switch >+ * between function versions to happen instantaneously by updating the klp_ops >+ * struct's func_stack list. The winner is the klp_func at the top of the >+ * func_stack (front of the list). >+ * >+ * @node: node for the global klp_ops list >+ * @func_stack: list head for the stack of klp_func's (active func is on top) >+ * @fops: registered ftrace ops struct >+ */ >+struct klp_ops { >+ struct list_head node; Not needed anymore. >+ struct list_head func_stack; >+ struct ftrace_ops fops; >+}; >+ > > diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c > index 52426665eecc..e4572bf34316 100644 > --- a/kernel/livepatch/core.c > +++ b/kernel/livepatch/core.c > @@ -760,6 +760,8 @@ static int klp_init_func(struct klp_object *obj, struct klp_func *func) > if (!func->old_name) > return -EINVAL; > > + func->ops = NULL; > + Any reason why it is not added a couple of lines later alongside the rest of the initialization? > /* > * NOPs get the address later. The patched module must be loaded, > * see klp_init_object_loaded(). > diff --git a/kernel/livepatch/patch.c b/kernel/livepatch/patch.c > index 90408500e5a3..8ab9c35570f4 100644 > --- a/kernel/livepatch/patch.c > +++ b/kernel/livepatch/patch.c > @@ -20,18 +20,25 @@ > #include "patch.h" > #include "transition.h" > > -static LIST_HEAD(klp_ops); > > struct klp_ops *klp_find_ops(void *old_func) > { > - struct klp_ops *ops; > + struct klp_patch *patch; > + struct klp_object *obj; > struct klp_func *func; > > - list_for_each_entry(ops, &klp_ops, node) { > - func = list_first_entry(&ops->func_stack, struct klp_func, > - stack_node); > - if (func->old_func == old_func) > - return ops; > + klp_for_each_patch(patch) { > + klp_for_each_object(patch, obj) { > + klp_for_each_func(obj, func) { > + /* > + * Ignore entry where func->ops has not been > + * assigned yet. It is most likely the one > + * which is about to be created/added. > + */ > + if (func->old_func == old_func && func->ops) > + return func->ops; > + } > + } > } The function is not used anywhere after this patch. Regards, Miroslav