From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E98FBFCC05D for ; Fri, 6 Mar 2026 19:01:14 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id EEEC56B0005; Fri, 6 Mar 2026 14:01:13 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id EA58B6B0088; Fri, 6 Mar 2026 14:01:13 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DCEBB6B0089; Fri, 6 Mar 2026 14:01:13 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id C65BD6B0005 for ; Fri, 6 Mar 2026 14:01:13 -0500 (EST) Received: from smtpin20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 7D8741A06F4 for ; Fri, 6 Mar 2026 19:01:13 +0000 (UTC) X-FDA: 84516556026.20.F3AA0F4 Received: from mail-wm1-f48.google.com (mail-wm1-f48.google.com [209.85.128.48]) by imf05.hostedemail.com (Postfix) with ESMTP id 573E8100027 for ; Fri, 6 Mar 2026 19:01:11 +0000 (UTC) Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=DSUPcnFK; spf=pass (imf05.hostedemail.com: domain of mjguzik@gmail.com designates 209.85.128.48 as permitted sender) smtp.mailfrom=mjguzik@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1772823671; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:references:dkim-signature; bh=egP4uheYvC9sMPollgo9xc+pktivTQM4ujp0h14jJjQ=; b=xB5Hxr3Ui3dvs1kPnMVtwP59sKwwu1uvv4yrNCrplAwdNUF8TULt4GVr4zKcLxdDaAqoea jZTHUwyA9+GUqTsP/MAzPMeZv6FMnwTGPWEmSB9pixMt0r6vW74hV4/F4hr+OWwx2XRT50 Uh1G5k+BpdteE23KF1qKAyzQnkTZEC4= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=DSUPcnFK; spf=pass (imf05.hostedemail.com: domain of mjguzik@gmail.com designates 209.85.128.48 as permitted sender) smtp.mailfrom=mjguzik@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1772823671; a=rsa-sha256; cv=none; b=QKfn/70zlntOU6pevB2YbVVPfSmLRbIBcXXa0TvIM5qMutp7elwP0+7Sc72UQDV1w0E7n8 rr35B5KovGQvnrbr3rLancNk3zbpE3HVwErq+YwGBiGvYg8P/W8EmROnW24S+4n6ntzsFa tqRZXAEdMsR7Psk6o3BfIRkw5MHNHEc= Received: by mail-wm1-f48.google.com with SMTP id 5b1f17b1804b1-48371bb515eso141758995e9.1 for ; Fri, 06 Mar 2026 11:01:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1772823670; x=1773428470; darn=kvack.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=egP4uheYvC9sMPollgo9xc+pktivTQM4ujp0h14jJjQ=; b=DSUPcnFKr22GuCxMjkfDrCQa4o3Nl8C5F8XpBdbuaH3uIHTCHfQvKwMCRgkgcLBFJ3 wJjsS9Ryf86ryNEWUoTUX+XVd+yVYScefdKoKhPSC5/rd/URC4CqhqzcKpayX3Nz1rkS F9wKimds7IFu/z/zQ5pYzLUB+O/g+vLj/ZQezX7WlnqXkoiQXHip0UsmHffE0suTK+1g NXfz9JNgr6kUtMxQb8VSHgppFZf0u2zGKvsdqAIE9KBtStm8o1rMSI3/nCHu3ZnU5B6+ DEfgBbA36mbkHzIXnGV+h9V4wiMYr95HcYhbbBcf7KxNAq6j62YxwLkj+R36GevdTVdN bdZA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772823670; x=1773428470; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=egP4uheYvC9sMPollgo9xc+pktivTQM4ujp0h14jJjQ=; b=IkK/gTD42Pl17DS6SctVCxWcIkyhgWj8bYZXDj9BkurfVQyO8E+T1WHhP0VVE+onVq X+Vqr76V2L4oEUX7ZZMhOeuK8YzqDAecUqkvyOJ2KwSZk2Bdv5aT5xDm+d+0lHTSVPae uP/6i3h5mL4PAmP2ubxkRyE7VocN3hNxsiB8cAt2PDdTnViOopBWxNyGCarxUDY9VXym ECDWFAaY6EerdVCo5s7jcQdKX8vzvRg5PEwUWa4uff+7xUMM8p20YwdFjTYySp78PZTg vWZGAZRZWkwXX+6zF91MwGVbrtbzvGwRBx88x+9DKJaHH+vXNFNqobabYDS4na1g/ON3 WwiQ== X-Forwarded-Encrypted: i=1; AJvYcCWFeitx+Ju/URv77MtZrfK89mQyVbNTat2ZoNhoFcjLU3NvW5quTxmBadCJpcAmyvq9UQlakwtdIw==@kvack.org X-Gm-Message-State: AOJu0YxppLIq+31/79LUOF6vlil0sV/cruvNG4RxvrX48QDpDWGssPjS sWDrolLvYzOWieczBp3QYjdfIxvJ7d6/bh7KzqH9PoNxLSkFdSAdPMgZ X-Gm-Gg: ATEYQzxRvkRV+sjYIW6Uoyl2fBXJnKMDXsb/JnzpsdMN8vndkQvrf2gb8zJThB+QUUh WcasynPx3a/6t/8jCqCs3SPYFxPTUQOT0gHtTIn2Emd81u3RFomVbvtIDo4Msdz8oO26bOkdk0A M6FBpIMcmSmRGr+fhzvj49G6cMSC52T3S8VHdtutEjYwJwM9GBi90pT+P8fTQ3QXHvIpbR+8BxI di3u+XqGnwc2SgQ6ZAt+2eFXBe+lyFyH7ReY8qMfwep7Y/K1C0ky2dVFAYvc32MpfIxv+HzuARL GO/254NKJ0t7xyYKC0QY/p4Jg/H0wik1qJoi+rK7TbUFGXTzdehTu2y+8NeYNLE69YWLgDRM+Ay tTCVbf6qUc3OsEKue8zVHjn1xfNj2fb5QipSJagy74HuCX8ge4zQg0NU8WVaF1yK2fz24kWEiwS 9meZRy0KacVVs/BjNzOX8wjjsqkWsoTYFgBil2XgjSnkFXatCrKWh5PgASv0irLseBPPgJFaw4Q GYFEd54NIxV X-Received: by 2002:a05:600c:8714:b0:477:6374:6347 with SMTP id 5b1f17b1804b1-48526957d50mr47893785e9.22.1772823669332; Fri, 06 Mar 2026 11:01:09 -0800 (PST) Received: from f.. (cst-prg-92-188.cust.vodafone.cz. [46.135.92.188]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4852767d8e4sm50717025e9.2.2026.03.06.11.01.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 06 Mar 2026 11:01:08 -0800 (PST) From: Mateusz Guzik To: brauner@kernel.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, oleg@redhat.com, Mateusz Guzik Subject: [PATCH] pid: cosmetic changes to alloc_pid() Date: Fri, 6 Mar 2026 20:01:00 +0100 Message-ID: <20260306190100.1900572-1-mjguzik@gmail.com> X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 573E8100027 X-Stat-Signature: bykx19ssns56hbkthscro6gbma6nxcn3 X-Rspam-User: X-HE-Tag: 1772823671-258261 X-HE-Meta: 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 mQUvrFX/ k0cjwqcQfYSwpQRm+yv2QxPAGBcyedKJ0fAAHTFQwhdxTm9yugwzLrbEn/2sJYhWeVZ+LI5HPLATKPCgFHIyZQFe+yGFUvq9eY6DDhZFH6Tl1PmfvZzIiIyQtZt70VPjeZdxDDSryeB4gogcsBYS/x570kpO5uxuWRKC1RDdGF6A9H9MgXxpqyVtT2mgCezVhgME1XA5IyD/4pEVUeO1OnjlJwlJR/QN7DtikXdqOvSJTiUBhJHB86Yncm8eHnlIbgYWvLprJJkuGaFm5AB9uXa3lMlzSWT0Efy8Ju3vwZ6vbQK9Cx6ZuTVmwwwLInoJtaf8otCXVSbDbHCJuSeXMq8+L/k4WAEFpJNM7D0BjOJzV9dSAigFHPJKmyybB12RcCwLYXiLhGOFgxcNzGb6taH8hjOhuquVHsa3p+mUcLQ6u5K1Gcl9XOQ3Sg2bLs4LElwOXdK7KbNTPUQk= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Commit 6d864a1b182532e7 ("pid: only take pidmap_lock once on alloc") landed v2 of the patch instead of v3. This patch remedies the problem. No functional changes. Signed-off-by: Mateusz Guzik --- kernel/pid.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/kernel/pid.c b/kernel/pid.c index 2f1dbcbc2349..dbe82062e683 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -177,7 +177,7 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *arg_set_tid, * for a process in all nested PID namespaces but arg_set_tid_size must * never be greater than the current ns->level + 1. */ - if (arg_set_tid_size > ns->level + 1) + if (unlikely(arg_set_tid_size > ns->level + 1)) return ERR_PTR(-EINVAL); /* @@ -186,7 +186,7 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *arg_set_tid, * 1. allocate and fill in pid struct */ pid = kmem_cache_alloc(ns->pid_cachep, GFP_KERNEL); - if (!pid) + if (unlikely(!pid)) return ERR_PTR(retval); get_pid_ns(ns); @@ -205,7 +205,7 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *arg_set_tid, * This stores found pid_max to make sure the used value is the same should * later code need it. */ - for (tmp = ns, i = ns->level; i >= 0; i--) { + for (tmp = ns, i = ns->level; i >= 0;) { pid_max[ns->level - i] = READ_ONCE(tmp->pid_max); if (arg_set_tid_size) { @@ -227,6 +227,7 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *arg_set_tid, } tmp = tmp->parent; + i--; } /* @@ -247,10 +248,9 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *arg_set_tid, tid + 1, GFP_ATOMIC); /* * If ENOSPC is returned it means that the PID is - * alreay in use. Return EEXIST in that case. + * already in use. Return EEXIST in that case. */ if (nr == -ENOSPC) - nr = -EEXIST; } else { int pid_min = 1; @@ -276,12 +276,11 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *arg_set_tid, * Preload more memory if idr_alloc{,cyclic} failed with -ENOMEM. * * The IDR API only allows us to preload memory for one call, while we may end - * up doing several under pidmap_lock with GFP_ATOMIC. The situation may be - * salvageable with GFP_KERNEL. But make sure to not loop indefinitely if preload - * did not help (the routine unfortunately returns void, so we have no idea - * if it got anywhere). + * up doing several with GFP_ATOMIC. It may be the situation is salvageable with + * GFP_KERNEL. But make sure to not loop indefinitely if preload did not help + * (the routine unfortunately returns void, so we have no idea if it got anywhere). * - * The lock can be safely dropped and picked up as historically pid allocation + * The pidmap lock can be safely dropped and picked up as historically pid allocation * for different namespaces was *not* atomic -- we try to hold on to it the * entire time only for performance reasons. */ -- 2.48.1