From patchwork Thu Feb 15 14:46:26 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mathieu Desnoyers X-Patchwork-Id: 13558571 Received: from smtpout.efficios.com (smtpout.efficios.com [167.114.26.122]) (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 BD4C2132470; Thu, 15 Feb 2024 14:46:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=167.114.26.122 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708008403; cv=none; b=cO6foGmzsI5XvlGJusSqjR6nK3GP01aPU5jX8X2rqpDcacRE7F7M8fKR8GmioXxmmsvBqF2BiReN6MQEDOPOJ5pwigFwx7rHLpCwME+hUO/omzFzR7zQa56faiukuNfimPWJPDeSwRhhF9riDvgL6jRWPcuTXH2H1PyaxNQHoI0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708008403; c=relaxed/simple; bh=JafNy954LGAswGK3M3iYUpQrWP3IyrMlG3pf6B1HRm4=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=UwEBek/XxdZGS+CaKSfTxD9j1Q+5q2F8oeXew/n/S9pxmnQZsHdPFITsEQwMXUpvUJzCgNLB4L5tiHRmCmZnasccrnpozN/pRDfmmCNjonQrbwxijmR1Xma66pn3b9qncmC0bEKgzb6BtDkvnRpjpNYN6PvOcmDkiQBzxBNk0+w= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=efficios.com; spf=pass smtp.mailfrom=efficios.com; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b=lJxsuurM; arc=none smtp.client-ip=167.114.26.122 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=efficios.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=efficios.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b="lJxsuurM" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=efficios.com; s=smtpout1; t=1708008399; bh=JafNy954LGAswGK3M3iYUpQrWP3IyrMlG3pf6B1HRm4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lJxsuurMOJq5+e74ZxcF+tIqPH0Qs+YhXRuSmvFSmLIGw0LXLL9OmA1TEc/hvC2zZ o91WMEukwLB1u4oCCHlgydXVguhQi11fEI6Vi8Ku08OyjSoiO2W2yeKDFGbjlSybRo grKnwo+y78PBVFCkNYKO8rAp12NTsmM88gHsKGJN+nzU5BYHEfglGxTm+PNhXBm4WX 1SH+QbvBu0shB1ITutjbBN/RvzwOVym/BdBANG0CF8gzUqRhhDPi+s7F1/D+ZD8taq b/ma0zxd+t86Hak1i/GDe5SYOKqW2uCqPPPfo+rNAEbyPVhQvm8B6Y94EIVbT9v+oc 6t/MP5Z/oCexQ== Received: from thinkos.internal.efficios.com (192-222-143-198.qc.cable.ebox.net [192.222.143.198]) by smtpout.efficios.com (Postfix) with ESMTPSA id 4TbHvM4gxZzZS5; Thu, 15 Feb 2024 09:46:39 -0500 (EST) From: Mathieu Desnoyers To: Dan Williams , Arnd Bergmann , Dave Chinner Cc: linux-kernel@vger.kernel.org, Mathieu Desnoyers , Andrew Morton , Linus Torvalds , Vishal Verma , Dave Jiang , Matthew Wilcox , Russell King , linux-arch@vger.kernel.org, linux-cxl@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-xfs@vger.kernel.org, dm-devel@lists.linux.dev, nvdimm@lists.linux.dev, linux-s390@vger.kernel.org Subject: [PATCH v6 2/9] dax: alloc_dax() return ERR_PTR(-EOPNOTSUPP) for CONFIG_DAX=n Date: Thu, 15 Feb 2024 09:46:26 -0500 Message-Id: <20240215144633.96437-3-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240215144633.96437-1-mathieu.desnoyers@efficios.com> References: <20240215144633.96437-1-mathieu.desnoyers@efficios.com> Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Change the return value from NULL to PTR_ERR(-EOPNOTSUPP) for CONFIG_DAX=n to be consistent with the fact that CONFIG_DAX=y never returns NULL. This is done in preparation for using cpu_dcache_is_aliasing() in a following change which will properly support architectures which detect data cache aliasing at runtime. Fixes: 4e4ced93794a ("dax: Move mandatory ->zero_page_range() check in alloc_dax()") Signed-off-by: Mathieu Desnoyers Reviewed-by: Dan Williams Cc: Andrew Morton Cc: Linus Torvalds Cc: Dan Williams Cc: Vishal Verma Cc: Dave Jiang Cc: Matthew Wilcox Cc: Arnd Bergmann Cc: Russell King Cc: linux-arch@vger.kernel.org Cc: linux-cxl@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-xfs@vger.kernel.org Cc: dm-devel@lists.linux.dev Cc: nvdimm@lists.linux.dev --- drivers/dax/super.c | 5 +++++ include/linux/dax.h | 6 +----- 2 files changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/dax/super.c b/drivers/dax/super.c index 0da9232ea175..205b888d45bf 100644 --- a/drivers/dax/super.c +++ b/drivers/dax/super.c @@ -319,6 +319,11 @@ EXPORT_SYMBOL_GPL(dax_alive); * that any fault handlers or operations that might have seen * dax_alive(), have completed. Any operations that start after * synchronize_srcu() has run will abort upon seeing !dax_alive(). + * + * Note, because alloc_dax() returns an ERR_PTR() on error, callers + * typically store its result into a local variable in order to check + * the result. Therefore, care must be taken to populate the struct + * device dax_dev field make sure the dax_dev is not leaked. */ void kill_dax(struct dax_device *dax_dev) { diff --git a/include/linux/dax.h b/include/linux/dax.h index e3ffe7c7f01d..9d3e3327af4c 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -88,11 +88,7 @@ static inline void *dax_holder(struct dax_device *dax_dev) static inline struct dax_device *alloc_dax(void *private, const struct dax_operations *ops) { - /* - * Callers should check IS_ENABLED(CONFIG_DAX) to know if this - * NULL is an error or expected. - */ - return NULL; + return ERR_PTR(-EOPNOTSUPP); } static inline void put_dax(struct dax_device *dax_dev) {