From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 6354F389E1E for ; Thu, 8 Jan 2026 09:26:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767864401; cv=none; b=XVV811GeSle82ubKEbwRLHWhB25K8DKFd9vcy6mhUn5A/slCsaW/BgaU2FVKF7z07iVxPK6Ri3OeHWlkkqzY4mo2FIOCeYWpiBCOBCAZz+von9LlJBFWrmttNbcRYtqJlr00TAN2kCCr+ZGqH9trvBBcVEhiBkQ2rrfuxrEdYFw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767864401; c=relaxed/simple; bh=3ENjzjjPPd94IkahyeP0CH1b3olon0SOAtCdPGjP63k=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=I04mM0/SXcwxx6tBfBZuDb6KnzlK9cEtwlVbvOjyjdfJ5VDK5tuXlP6efEqz9EL2bPjX+R6dqT275nWQnR0ZgTP+aoRukBmw1YKtwAe9euaViCVAGRdE+n5G557LmKnNTJARBAt9HhcmGykRy1JNprne+1l+nQBUwDlfKP64T9w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=mAQP0quk; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="mAQP0quk" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=4RLXqXBKFRlBzUZ5Cyif1n5sbWegRhfwmjKUo2zL7Ag=; b=mAQP0qukxunv17b8O4Ty00zeqd TVLc4moedheBFNA21bEGjNoxiNHPHexglr6PsHs4aWjtINejSi90TdXAkDS8l07UC6Nac4m5w7MS3 uG6fHDt9gR4fnQ5b4J9Z0I9VmAJOnDiQpbC3VH7gav5g/k9FMX4dB7Q0+he58zuzn+GRjgX1lAeAk c47sqK3xRBUC9pempb2RwAn18MT55KiNEcrTeJGRbLvTd61O7RnLbCg5/A22laXJE7xhWShb7XCIC wFblOxMPqiODtn+QPs5HEW0QNgCGthu3BSBw89dZ4wWX3wiWDleCRx2+1oBJFuiO/A82kOPfQRW/m +mIqB3iQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vdmHl-0000000GSK2-22Mh; Thu, 08 Jan 2026 09:26:29 +0000 Date: Thu, 8 Jan 2026 01:26:29 -0800 From: Christoph Hellwig To: NeilBrown Cc: Chuck Lever , Christoph Hellwig , Jeff Layton , Olga Kornievskaia , Dai Ngo , Tom Talpey , linux-nfs@vger.kernel.org, "Matthew Wilcox (Oracle)" Subject: Re: [PATCH v5] NFSD: Track SCSI Persistent Registration Fencing per Client with xarray Message-ID: References: <20251227042437.671409-1-cel@kernel.org> <9e127bfa-e4c9-4e06-b5ad-bb375e7d8e2b@app.fastmail.com> <176783380243.16766.17752014824707434037@noble.neil.brown.name> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <176783380243.16766.17752014824707434037@noble.neil.brown.name> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Thu, Jan 08, 2026 at 11:56:42AM +1100, NeilBrown wrote: > > > Only in the most abstract way, xa_store actually stores the new > > > entry/value and returns the old one. In other words, this does > > > quite a bit of work for the non-initial GETDEVICEINFO. > > > > The comment is misleading then, and should be clarified. > > > > But should the code use xa_insert instead of xa_store ? > > or xa_cmpxchg() to replace NULL with a value?? xa_insert seems like a lot less heavy handed.