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Howlett" , Lorenzo Stoakes , Michal Hocko , Suren Baghdasaryan , Vlastimil Babka , Zi Yan , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 0/3] mm: treewide: make get_free_pages() and return void * Message-ID: References: <20251018093002.3660549-1-rppt@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Stat-Signature: 8jezzzsiztfaugtq4796uq4ts9hwn9fd X-Rspamd-Queue-Id: 8A7782000D X-Rspamd-Server: rspam09 X-HE-Tag: 1760883926-880144 X-HE-Meta: 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 LLV9G03j y9872mUhzzLT/WJd/annG6/aTTDWD65vJl3tXBlBbMyZDkTXlfW/OQFIjFz4gHCJpTOooEyevAXsgUOh5dCk0hd+D8E/3gyWLSwUs3gmCmG9urMSl33CIXUDGbfrew5Nal7stelP3t+PZdFCq7Y7lX5hUJlBLP+fDzgOlZnFphmt5oVu4zQksw/jGFKJOMuuGT7q6/PhGGblXKrTHaRfZeIjERNSTgIndltEfEen290UrnUoiZuurzv+yIkVjeQtVwi8/6bEmGH8/nyOdCptEemgPwow0fX9G8fKI75F8Tx0uslM= 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 Sun, Oct 19, 2025 at 01:30:47AM +0100, Matthew Wilcox wrote: > On Sat, Oct 18, 2025 at 12:29:59PM +0300, Mike Rapoport wrote: > > Vast majority of allocations that use get_free_pages() and its derivatives > > cast the returned unsigned long to a pointer and then cast it back to > > unsigned long when freeing the memory. > > > > These castings are useless and only obfuscate the code. > > > > Make get_free_pages() and friends return 'void *' and free_pages() accept > > 'void *' as its address parameter. > > No. Linus has rejected this change before. I can't find it now, it was > a long time ago. If it was a long time ago, he might not object it now. > Most of them shouldn't be using get_free_pages() at all, they should be > using kmalloc(). Don't know if most but some of them could. Still, we'd have a bunch of get_free_pages() users with needless castings. And converting callers that should use kmalloc() is a long and tedious process, while here we get an API improvement in a single automated change. -- Sincerely yours, Mike.