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Howlett" , Linus Torvalds , linux-arm-kernel@axis.com, linux-arm-kernel@lists.infradead.org, linux-crypto@vger.kernel.org, linux-ide@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mips@vger.kernel.org, linux-mmc@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, Marco Elver , Marek Szyprowski , Michal Hocko , Mike Rapoport , Muchun Song , netdev@vger.kernel.org, Oscar Salvador , Peter Xu , Robin Murphy , Suren Baghdasaryan , Tejun Heo , virtualization@lists.linux.dev, Vlastimil Babka , wireguard@lists.zx2c4.com, x86@kernel.org, Zi Yan Subject: [PATCH v2 20/37] io_uring/zcrx: remove nth_page() usage within folio Date: Mon, 1 Sep 2025 17:03:41 +0200 Message-ID: <20250901150359.867252-21-david@redhat.com> In-Reply-To: <20250901150359.867252-1-david@redhat.com> References: <20250901150359.867252-1-david@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Within a folio/compound page, nth_page() is no longer required. Given that we call folio_test_partial_kmap()+kmap_local_page(), the code would already be problematic if the pages would span multiple folios. So let's just assume that all src pages belong to a single folio/compound page and can be iterated ordinarily. The dst page is currently always a single page, so we're not actually iterating anything. Reviewed-by: Pavel Begunkov Reviewed-by: Lorenzo Stoakes Cc: Jens Axboe Cc: Pavel Begunkov Signed-off-by: David Hildenbrand --- io_uring/zcrx.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/io_uring/zcrx.c b/io_uring/zcrx.c index e5ff49f3425e0..18c12f4b56b6c 100644 --- a/io_uring/zcrx.c +++ b/io_uring/zcrx.c @@ -975,9 +975,9 @@ static ssize_t io_copy_page(struct io_copy_cache *cc, struct page *src_page, if (folio_test_partial_kmap(page_folio(dst_page)) || folio_test_partial_kmap(page_folio(src_page))) { - dst_page = nth_page(dst_page, dst_offset / PAGE_SIZE); + dst_page += dst_offset / PAGE_SIZE; dst_offset = offset_in_page(dst_offset); - src_page = nth_page(src_page, src_offset / PAGE_SIZE); + src_page += src_offset / PAGE_SIZE; src_offset = offset_in_page(src_offset); n = min(PAGE_SIZE - src_offset, PAGE_SIZE - dst_offset); n = min(n, len); -- 2.50.1