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b=Vco4K2eVYGfYGyg5YaHsmWN+3k6nNiSCNBYy6ngq88ATZov79V6nUDRzIi5gwzstW Xe7q49t6AGV0dD46I6vdQAJAcYLbbMv3RM6KVHqgIHtILpg4//ZwtHtO2eM64ocX/u waAtNhTJ6/rZKk9j1bXufCWyDqAlo2vSH5JRjOVPC5m5FhVh3YZ2CCeUyKe6CR2WPC H6pViBJAdyPUW24cVSC2qToLalSQRX9J6o0/2Dex+E9Bw3upHJxQzt0exEnHFECSUN oWp8B654jSXWaDNW7NlNhsKGOuTWNqowQUgT3P23de8tG70lFk+sAVQcQlkvs8q8xl udORXqwFbHOkw== Date: Sun, 2 Nov 2025 08:51:24 +0200 From: Mike Rapoport To: Pasha Tatashin Cc: akpm@linux-foundation.org, brauner@kernel.org, corbet@lwn.net, graf@amazon.com, jgg@ziepe.ca, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, masahiroy@kernel.org, ojeda@kernel.org, pratyush@kernel.org, rdunlap@infradead.org, tj@kernel.org, yanjun.zhu@linux.dev Subject: Re: [PATCH v9 4/9] memblock: Unpreserve memory in case of error Message-ID: References: <20251101142325.1326536-1-pasha.tatashin@soleen.com> <20251101142325.1326536-5-pasha.tatashin@soleen.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251101142325.1326536-5-pasha.tatashin@soleen.com> X-Rspamd-Server: rspam05 X-Stat-Signature: 3zmnpfqy8kajp7m1dj1axh8dnst3isga X-Rspam-User: X-Rspamd-Queue-Id: EBF7114000B X-HE-Tag: 1762066294-241883 X-HE-Meta: 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sat, Nov 01, 2025 at 10:23:20AM -0400, Pasha Tatashin wrote: > If there is an error half way through KHO memory preservation, we should > rollback and unpreserve everything that is partially preserved. > > Signed-off-by: Pasha Tatashin > Suggested-by: Pratyush Yadav Reviewed-by: Mike Rapoport (Microsoft) with a small nit below. > --- > mm/memblock.c | 73 ++++++++++++++++++++++++++++++++++++++++----------- > 1 file changed, 58 insertions(+), 15 deletions(-) > > diff --git a/mm/memblock.c b/mm/memblock.c > index e3bef9b35d63..f527ad1ca682 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -2445,29 +2445,60 @@ int reserve_mem_release_by_name(const char *name) ... > static int __init prepare_kho_fdt(void) > { > - int err = 0, i; > struct page *fdt_page; > void *fdt; > + int err; > > fdt_page = alloc_page(GFP_KERNEL); > - if (!fdt_page) > - return -ENOMEM; > + if (!fdt_page) { > + err = -ENOMEM; > + goto err_no_fdt_page; Please rename the label to describe what the goto does, say, err_report. I believe it can be a fixup on top after Andrew merges these. ... > +err_remove_subtree: > + kho_remove_subtree(fdt); > +err_unpreserve_fdt: > + kho_unpreserve_pages(fdt_page, 1); > +err_free_fdt: > + put_page(fdt_page); > +err_no_fdt_page: > + pr_err("failed to prepare memblock FDT for KHO: %d\n", err); > > return err; > } > -- > 2.51.1.930.gacf6e81ea2-goog > -- Sincerely yours, Mike.