From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794450892; b=W2zc5DGyo46WF2xb8eQxb8QhASfwL+4gTZYERNGLzH6nZcMsulloWNQSsrPo0g5OeVBH knXG9uSKXzgoxtvHuQhRdMnW4VAdMmPW+m12/FNpFv+r9NW9SevLy1UsRr+yNMeMemtSB 35ZDlKw3iSdKT1Mqo8ei/aTmtKErvdAZVUUDGVnEBc3XIxkUFEdAzVVVoIUDSROt9/iMt 3+69dq8JCLXr+eGI+WHn3bVXKV/K3x7Zwv+qIQgOE3jcVr3OyHdsSaWgONLXVy3jGQ1PO ptiFiXkMUOl54j1Xn8OKyI5znc6QGPEzbBvHI+Qm6ZfpwCBCiI6SCT10WBediovsEZw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794450892; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=OrHFq+vpUFZgOzQwSFfGF33qyM25Z/c5KwjiuMBu+2g=; b=R7KqbbnQOC50uCRDmezC8u4sH/QQjsYARFZrUwZ0RJrjCP8qlWJgrrPR0Tm4BRqoK9VY SoVN7re2yBGgjMnFGn4cpllRPqd0u1zQ6n9i4i54Rtb76QbzieFQ6QYuZ5rbFWonkrrAt clTJK6zfsZ6RmHux9hO8mPC2oQWAHg07m/tyYYMG7yFH2TYfBZ87hhgGG43p/m+iBTj6l S+TMMVyB2WCnJuxF3GGhyiXB9tXHG77QZn8mLTUuSTHTET27oLb5bkIpI3+QmLtdOs1SX edanJUW1W9SF+1lNW3W0KbkSKCSxR41mb5dZs+0NXMB1OUHAtKX+p/q1XNmSuIPO1Ug== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=PTnIsKxT; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D1061606A321 for ; Thu, 12 Nov 2026 02:34:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=PTnIsKxT Received: by smtp.kernel.org (Postfix) with ESMTPSA id B3DDC1F00A06; Thu, 12 Nov 2026 02:34:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794450892; bh=OrHFq+vpUFZgOzQwSFfGF33qyM25Z/c5KwjiuMBu+2g=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=PTnIsKxTZysvoolXoXoi54ElknvR94J2G/prC9L3MIDjGR47pXoaTkKvqup/VBrkS m6NQ34mP4EU1c5DTH/UVBm14H/eoUIPu6moG1JfQUQLA89I8moK0uepLXwQKaSNxWy jbQSf2nGMW3cvhz8HN/i7IEn730hbZsKpHXSSte8mdSDDihK7dZuXrWj4rdOO0Wp4X KSyFmC0NSWIOzUxeBst+vAyMwZfyG7fOQNW/f39ltyN3lANErEltzRkeKFqxiaEQVI pGA9ytFUUIe8jyF3WAEHT+kQCSQZ/FYi6jzUG/oI5MfuItcpr7x/s74wzy+kqcJgNX I7St1XMOzSLSQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Alistair Popple , David Hildenbrand , Jason Gunthorpe , Dan Williams , John Hubbard , Oscar Salvador , Peter Xu , Andrew Morton , Sasha Levin Subject: [PATCH 6.12.y 3/4] mm/gup: remove dead pgmap refcounting code Date: Wed, 11 Nov 2026 21:34:43 -0500 Message-ID: <20261112023429.1348841-3-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261112023429.1348841-1-sashal@kernel.org> References: <20261109200900-failed-6.12-79cb51d538ab@kernel.org> <20261112023429.1348841-1-sashal@kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Alistair Popple [ Upstream commit d3f7922b929a92873e14f7c61a026a6b576e8773 ] Prior to commit aed877c2b425 ("device/dax: properly refcount device dax pages when mapping") ZONE_DEVICE pages were not fully reference counted when mapped into user page tables. Instead GUP would take a reference on the associated pgmap to ensure the results of pfn_to_page() remained valid. This is no longer required and most of the code was removed by commit fd2825b0760a ("mm/gup: remove pXX_devmap usage from get_user_pages()"). Finish cleaning this up by removing the dead calls to put_dev_pagemap() and the temporary context struct. Link: https://lkml.kernel.org/r/20250903225926.34702-1-apopple@nvidia.com Signed-off-by: Alistair Popple Acked-by: David Hildenbrand Reviewed-by: Jason Gunthorpe Reviewed-by: Dan Williams Reviewed-by: John Hubbard Cc: Oscar Salvador Cc: Peter Xu Signed-off-by: Andrew Morton Stable-dep-of: 79cb51d538ab ("mm/gup: recheck the PUD under PTL in follow_pud_mask()") Signed-off-by: Sasha Levin --- mm/gup.c | 67 ++++++++++++++++++++++---------------------------------- 1 file changed, 26 insertions(+), 41 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index 914e586137a2f..b8367869f7928 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -27,11 +27,6 @@ #include "internal.h" -struct follow_page_context { - struct dev_pagemap *pgmap; - unsigned int page_mask; -}; - static inline void sanity_check_pinned_pages(struct page **pages, unsigned long npages) { @@ -624,7 +619,7 @@ static struct page *no_page_table(struct vm_area_struct *vma, #ifdef CONFIG_PGTABLE_HAS_HUGE_LEAVES static struct page *follow_huge_pud(struct vm_area_struct *vma, unsigned long addr, pud_t *pudp, - int flags, struct follow_page_context *ctx) + int flags, unsigned long *page_mask) { struct mm_struct *mm = vma->vm_mm; struct page *page; @@ -650,7 +645,7 @@ static struct page *follow_huge_pud(struct vm_area_struct *vma, if (ret) page = ERR_PTR(ret); else - ctx->page_mask = HPAGE_PUD_NR - 1; + *page_mask = HPAGE_PUD_NR - 1; return page; } @@ -696,7 +691,7 @@ static inline bool can_follow_write_pmd(pmd_t pmd, struct page *page, static struct page *follow_huge_pmd(struct vm_area_struct *vma, unsigned long addr, pmd_t *pmd, unsigned int flags, - struct follow_page_context *ctx) + unsigned long *page_mask) { struct mm_struct *mm = vma->vm_mm; pmd_t pmdval = *pmd; @@ -733,7 +728,7 @@ static struct page *follow_huge_pmd(struct vm_area_struct *vma, #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; - ctx->page_mask = HPAGE_PMD_NR - 1; + *page_mask = HPAGE_PMD_NR - 1; return page; } @@ -741,7 +736,7 @@ static struct page *follow_huge_pmd(struct vm_area_struct *vma, #else /* CONFIG_PGTABLE_HAS_HUGE_LEAVES */ static struct page *follow_huge_pud(struct vm_area_struct *vma, unsigned long addr, pud_t *pudp, - int flags, struct follow_page_context *ctx) + int flags, unsigned long *page_mask) { return NULL; } @@ -749,7 +744,7 @@ static struct page *follow_huge_pud(struct vm_area_struct *vma, static struct page *follow_huge_pmd(struct vm_area_struct *vma, unsigned long addr, pmd_t *pmd, unsigned int flags, - struct follow_page_context *ctx) + unsigned long *page_mask) { return NULL; } @@ -815,8 +810,7 @@ static inline bool can_follow_write_pte(pte_t pte, struct page *page, } static struct page *follow_page_pte(struct vm_area_struct *vma, - unsigned long address, pmd_t *pmd, unsigned int flags, - struct dev_pagemap **pgmap) + unsigned long address, pmd_t *pmd, unsigned int flags) { struct mm_struct *mm = vma->vm_mm; struct folio *folio; @@ -919,7 +913,7 @@ static struct page *follow_page_pte(struct vm_area_struct *vma, static struct page *follow_pmd_mask(struct vm_area_struct *vma, unsigned long address, pud_t *pudp, unsigned int flags, - struct follow_page_context *ctx) + unsigned long *page_mask) { pmd_t *pmd, pmdval; spinlock_t *ptl; @@ -933,7 +927,7 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma, if (!pmd_present(pmdval)) return no_page_table(vma, flags, address); if (likely(!pmd_leaf(pmdval))) - return follow_page_pte(vma, address, pmd, flags, &ctx->pgmap); + return follow_page_pte(vma, address, pmd, flags); if (pmd_protnone(pmdval) && !gup_can_follow_protnone(vma, flags)) return no_page_table(vma, flags, address); @@ -946,16 +940,16 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma, } if (unlikely(!pmd_leaf(pmdval))) { spin_unlock(ptl); - return follow_page_pte(vma, address, pmd, flags, &ctx->pgmap); + return follow_page_pte(vma, address, pmd, flags); } if (pmd_trans_huge(pmdval) && (flags & FOLL_SPLIT_PMD)) { spin_unlock(ptl); split_huge_pmd(vma, pmd, address); /* If pmd was left empty, stuff a page table in there quickly */ return pte_alloc(mm, pmd) ? ERR_PTR(-ENOMEM) : - follow_page_pte(vma, address, pmd, flags, &ctx->pgmap); + follow_page_pte(vma, address, pmd, flags); } - page = follow_huge_pmd(vma, address, pmd, flags, ctx); + page = follow_huge_pmd(vma, address, pmd, flags, page_mask); spin_unlock(ptl); return page; } @@ -963,7 +957,7 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma, static struct page *follow_pud_mask(struct vm_area_struct *vma, unsigned long address, p4d_t *p4dp, unsigned int flags, - struct follow_page_context *ctx) + unsigned long *page_mask) { pud_t *pudp, pud; spinlock_t *ptl; @@ -976,7 +970,7 @@ static struct page *follow_pud_mask(struct vm_area_struct *vma, return no_page_table(vma, flags, address); if (pud_leaf(pud)) { ptl = pud_lock(mm, pudp); - page = follow_huge_pud(vma, address, pudp, flags, ctx); + page = follow_huge_pud(vma, address, pudp, flags, page_mask); spin_unlock(ptl); if (page) return page; @@ -985,13 +979,13 @@ static struct page *follow_pud_mask(struct vm_area_struct *vma, if (unlikely(pud_bad(pud))) return no_page_table(vma, flags, address); - return follow_pmd_mask(vma, address, pudp, flags, ctx); + return follow_pmd_mask(vma, address, pudp, flags, page_mask); } static struct page *follow_p4d_mask(struct vm_area_struct *vma, unsigned long address, pgd_t *pgdp, unsigned int flags, - struct follow_page_context *ctx) + unsigned long *page_mask) { p4d_t *p4dp, p4d; @@ -1002,7 +996,7 @@ static struct page *follow_p4d_mask(struct vm_area_struct *vma, if (!p4d_present(p4d) || p4d_bad(p4d)) return no_page_table(vma, flags, address); - return follow_pud_mask(vma, address, p4dp, flags, ctx); + return follow_pud_mask(vma, address, p4dp, flags, page_mask); } /** @@ -1010,20 +1004,16 @@ static struct page *follow_p4d_mask(struct vm_area_struct *vma, * @vma: vm_area_struct mapping @address * @address: virtual address to look up * @flags: flags modifying lookup behaviour - * @ctx: contains dev_pagemap for %ZONE_DEVICE memory pinning and a - * pointer to output page_mask + * @page_mask: a pointer to output page_mask * * @flags can have FOLL_ flags set, defined in * - * When getting pages from ZONE_DEVICE memory, the @ctx->pgmap caches - * the device's dev_pagemap metadata to avoid repeating expensive lookups. - * * When getting an anonymous page and the caller has to trigger unsharing * of a shared anonymous page first, -EMLINK is returned. The caller should * trigger a fault with FAULT_FLAG_UNSHARE set. Note that unsharing is only * relevant with FOLL_PIN and !FOLL_WRITE. * - * On output, the @ctx->page_mask is set according to the size of the page. + * On output, @page_mask is set according to the size of the page. * * Return: the mapped (struct page *), %NULL if no mapping exists, or * an error pointer if there is a mapping to something not represented @@ -1031,7 +1021,7 @@ static struct page *follow_p4d_mask(struct vm_area_struct *vma, */ static struct page *follow_page_mask(struct vm_area_struct *vma, unsigned long address, unsigned int flags, - struct follow_page_context *ctx) + unsigned long *page_mask) { pgd_t *pgd; struct mm_struct *mm = vma->vm_mm; @@ -1039,13 +1029,13 @@ static struct page *follow_page_mask(struct vm_area_struct *vma, vma_pgtable_walk_begin(vma); - ctx->page_mask = 0; + *page_mask = 0; pgd = pgd_offset(mm, address); if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) page = no_page_table(vma, flags, address); else - page = follow_p4d_mask(vma, address, pgd, flags, ctx); + page = follow_p4d_mask(vma, address, pgd, flags, page_mask); vma_pgtable_walk_end(vma); @@ -1389,7 +1379,7 @@ static long __get_user_pages(struct mm_struct *mm, { long ret = 0, i = 0; struct vm_area_struct *vma = NULL; - struct follow_page_context ctx = { NULL }; + unsigned long page_mask = 0; if (!nr_pages) return 0; @@ -1427,7 +1417,7 @@ static long __get_user_pages(struct mm_struct *mm, pages ? &page : NULL); if (ret) goto out; - ctx.page_mask = 0; + page_mask = 0; goto next_page; } @@ -1450,7 +1440,7 @@ static long __get_user_pages(struct mm_struct *mm, } cond_resched(); - page = follow_page_mask(vma, start, gup_flags, &ctx); + page = follow_page_mask(vma, start, gup_flags, &page_mask); if (!page || PTR_ERR(page) == -EMLINK) { ret = faultin_page(vma, start, gup_flags, PTR_ERR(page) == -EMLINK, locked); @@ -1483,7 +1473,7 @@ static long __get_user_pages(struct mm_struct *mm, goto out; } next_page: - page_increm = 1 + (~(start >> PAGE_SHIFT) & ctx.page_mask); + page_increm = 1 + (~(start >> PAGE_SHIFT) & page_mask); if (page_increm > nr_pages) page_increm = nr_pages; @@ -1533,8 +1523,6 @@ static long __get_user_pages(struct mm_struct *mm, nr_pages -= page_increm; } while (nr_pages); out: - if (ctx.pgmap) - put_dev_pagemap(ctx.pgmap); return i ? i : ret; } @@ -2894,7 +2882,6 @@ static int gup_fast_pte_range(pmd_t pmd, pmd_t *pmdp, unsigned long addr, unsigned long end, unsigned int flags, struct page **pages, int *nr) { - struct dev_pagemap *pgmap = NULL; int ret = 0; pte_t *ptep, *ptem; @@ -2966,8 +2953,6 @@ static int gup_fast_pte_range(pmd_t pmd, pmd_t *pmdp, unsigned long addr, ret = 1; pte_unmap: - if (pgmap) - put_dev_pagemap(pgmap); pte_unmap(ptem); return ret; } -- 2.53.0