From 30f62b92e632d13420381f54210ad9d84d79b209 Mon Sep 17 00:00:00 2001 From: "Vishal Moola (Oracle)" Date: Tue, 29 Apr 2025 18:00:58 -0700 Subject: [PATCH] mm/gup: remove unnecessary check in memfd_pin_folios() Patch series "mm/gup: Cleanup memfd_pin_folios()". A couple straightforward cleanups to memfd_pin_folios() found through code inspection. Saves 124 bytes of kernel text overall and makes the code more readable. This patch (of 2): Commit 89c1905d9c14 ("mm/gup: introduce memfd_pin_folios() for pinning memfd folios") checks if filemap_get_folios_contig() returned duplicate folios to prevent multiple attempts at pinning the same folio. Commit 8ab1b1602396 ("mm: fix filemap_get_folios_contig returning batches of identical folios") ensures that filemap_get_folios_contig() returns a batch of distinct folios. We can remove the duplicate folio check to simplify the code and save 58 bytes of text. Link: https://lkml.kernel.org/r/20250430010059.892632-1-vishal.moola@gmail.com Link: https://lkml.kernel.org/r/20250430010059.892632-2-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) Acked-by: David Hildenbrand Cc: Vivek Kasireddy Signed-off-by: Andrew Morton --- mm/gup.c | 15 +-------------- 1 file changed, 1 insertion(+), 14 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index 91bbf57579f0c..e6e2a93868509 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -3590,7 +3590,7 @@ long memfd_pin_folios(struct file *memfd, loff_t start, loff_t end, { unsigned int flags, nr_folios, nr_found; unsigned int i, pgshift = PAGE_SHIFT; - pgoff_t start_idx, end_idx, next_idx; + pgoff_t start_idx, end_idx; struct folio *folio = NULL; struct folio_batch fbatch; struct hstate *h; @@ -3640,19 +3640,7 @@ long memfd_pin_folios(struct file *memfd, loff_t start, loff_t end, folio = NULL; } - next_idx = 0; for (i = 0; i < nr_found; i++) { - /* - * As there can be multiple entries for a - * given folio in the batch returned by - * filemap_get_folios_contig(), the below - * check is to ensure that we pin and return a - * unique set of folios between start and end. - */ - if (next_idx && - next_idx != folio_index(fbatch.folios[i])) - continue; - folio = page_folio(&fbatch.folios[i]->page); if (try_grab_folio(folio, 1, FOLL_PIN)) { @@ -3665,7 +3653,6 @@ long memfd_pin_folios(struct file *memfd, loff_t start, loff_t end, *offset = offset_in_folio(folio, start); folios[nr_folios] = folio; - next_idx = folio_next_index(folio); if (++nr_folios == max_folios) break; } -- 2.39.5