From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Claudio Imbrenda Subject: [PATCH v4 1/2] mm/gup: fixup for 9947ea2c1e608e32 "mm/gup: track FOLL_PIN pages" Date: Fri, 6 Mar 2020 14:25:36 +0100 In-Reply-To: <20200306132537.783769-1-imbrenda@linux.ibm.com> References: <20200306132537.783769-1-imbrenda@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-Id: <20200306132537.783769-2-imbrenda@linux.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: To: linux-next@vger.kernel.org, akpm@linux-foundation.org, jack@suse.cz, kirill@shutemov.name Cc: borntraeger@de.ibm.com, david@redhat.com, aarcange@redhat.com, linux-mm@kvack.org, frankja@linux.ibm.com, sfr@canb.auug.org.au, jhubbard@nvidia.com, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org In case pin fails, we need to unpin, a simple put_page will not be enough fixup for commit 9947ea2c1e608e32 ("mm/gup: track FOLL_PIN pages") it can be simply squashed in Signed-off-by: Claudio Imbrenda Reviewed-by: John Hubbard --- mm/gup.c | 46 +++++++++++++++++++++++----------------------- 1 file changed, 23 insertions(+), 23 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index f589299b0d4a..81a95fbe9901 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -116,6 +116,28 @@ static __maybe_unused struct page *try_grab_compound_head(struct page *page, return NULL; } +static void put_compound_head(struct page *page, int refs, unsigned int flags) +{ + if (flags & FOLL_PIN) { + mod_node_page_state(page_pgdat(page), NR_FOLL_PIN_RELEASED, + refs); + + if (hpage_pincount_available(page)) + hpage_pincount_sub(page, refs); + else + refs *= GUP_PIN_COUNTING_BIAS; + } + + VM_BUG_ON_PAGE(page_ref_count(page) < refs, page); + /* + * Calling put_page() for each ref is unnecessarily slow. Only the last + * ref needs a put_page(). + */ + if (refs > 1) + page_ref_sub(page, refs - 1); + put_page(page); +} + /** * try_grab_page() - elevate a page's refcount by a flag-dependent amount * @@ -2134,7 +2156,7 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, goto pte_unmap; if (unlikely(pte_val(pte) != pte_val(*ptep))) { - put_page(head); + put_compound_head(head, 1, flags); goto pte_unmap; } @@ -2267,28 +2289,6 @@ static int record_subpages(struct page *page, unsigned long addr, return nr; } -static void put_compound_head(struct page *page, int refs, unsigned int flags) -{ - if (flags & FOLL_PIN) { - mod_node_page_state(page_pgdat(page), NR_FOLL_PIN_RELEASED, - refs); - - if (hpage_pincount_available(page)) - hpage_pincount_sub(page, refs); - else - refs *= GUP_PIN_COUNTING_BIAS; - } - - VM_BUG_ON_PAGE(page_ref_count(page) < refs, page); - /* - * Calling put_page() for each ref is unnecessarily slow. Only the last - * ref needs a put_page(). - */ - if (refs > 1) - page_ref_sub(page, refs - 1); - put_page(page); -} - #ifdef CONFIG_ARCH_HAS_HUGEPD static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end, unsigned long sz) -- 2.24.1