From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Christian Borntraeger <borntraeger@de.ibm.com>,
Janosch Frank <frankja@linux.vnet.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: KVM <kvm@vger.kernel.org>, Cornelia Huck <cohuck@redhat.com>,
David Hildenbrand <david@redhat.com>,
Thomas Huth <thuth@redhat.com>,
Ulrich Weigand <Ulrich.Weigand@de.ibm.com>,
Claudio Imbrenda <imbrenda@linux.ibm.com>,
linux-s390 <linux-s390@vger.kernel.org>,
Michael Mueller <mimu@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Andrea Arcangeli <aarcange@redhat.com>,
linux-mm@kvack.org, Will Deacon <will@kernel.org>,
Sean Christopherson <sean.j.christopherson@intel.com>
Subject: [PATCH v2 39/42] example for future extension: mm:gup/writeback: add callbacks for inaccessible pages: error cases
Date: Fri, 14 Feb 2020 17:26:55 -0500 [thread overview]
Message-ID: <20200214222658.12946-40-borntraeger@de.ibm.com> (raw)
In-Reply-To: <20200214222658.12946-1-borntraeger@de.ibm.com>
From: Claudio Imbrenda <imbrenda@linux.ibm.com>
This is a potential extension to do error handling if we fail to
make the page accessible if we know what others need.
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
---
mm/gup.c | 17 ++++++++++++-----
mm/page-writeback.c | 6 +++++-
2 files changed, 17 insertions(+), 6 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index a1c15d029f7c..354bcfbd844b 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -193,6 +193,7 @@ static struct page *follow_page_pte(struct vm_area_struct *vma,
struct page *page;
spinlock_t *ptl;
pte_t *ptep, pte;
+ int ret;
/* FOLL_GET and FOLL_PIN are mutually exclusive. */
if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) ==
@@ -250,8 +251,6 @@ static struct page *follow_page_pte(struct vm_area_struct *vma,
if (is_zero_pfn(pte_pfn(pte))) {
page = pte_page(pte);
} else {
- int ret;
-
ret = follow_pfn_pte(vma, address, ptep, flags);
page = ERR_PTR(ret);
goto out;
@@ -259,7 +258,6 @@ static struct page *follow_page_pte(struct vm_area_struct *vma,
}
if (flags & FOLL_SPLIT && PageTransCompound(page)) {
- int ret;
get_page(page);
pte_unmap_unlock(ptep, ptl);
lock_page(page);
@@ -276,7 +274,12 @@ static struct page *follow_page_pte(struct vm_area_struct *vma,
page = ERR_PTR(-ENOMEM);
goto out;
}
- arch_make_page_accessible(page);
+ ret = arch_make_page_accessible(page);
+ if (ret) {
+ put_page(page);
+ page = ERR_PTR(ret);
+ goto out;
+ }
}
if (flags & FOLL_TOUCH) {
if ((flags & FOLL_WRITE) &&
@@ -1920,7 +1923,11 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
VM_BUG_ON_PAGE(compound_head(page) != head, page);
- arch_make_page_accessible(page);
+ ret = arch_make_page_accessible(page);
+ if (ret) {
+ put_page(head);
+ goto pte_unmap;
+ }
SetPageReferenced(page);
pages[*nr] = page;
(*nr)++;
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 4c020e4ae71c..558d7063c117 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2807,7 +2807,11 @@ int __test_set_page_writeback(struct page *page, bool keep_write)
inc_zone_page_state(page, NR_ZONE_WRITE_PENDING);
}
unlock_page_memcg(page);
- arch_make_page_accessible(page);
+ /*
+ * If writeback has been triggered on a page that cannot be made
+ * accessible, it is too late.
+ */
+ WARN_ON(arch_make_page_accessible(page));
return ret;
}
--
2.25.0
next prev parent reply other threads:[~2020-02-14 22:27 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-14 22:26 [PATCH v2 00/42] KVM: s390: Add support for protected VMs Christian Borntraeger
2020-02-14 22:26 ` [PATCH v2 01/42] mm:gup/writeback: add callbacks for inaccessible pages Christian Borntraeger
2020-02-17 9:14 ` David Hildenbrand
2020-02-17 11:10 ` Christian Borntraeger
2020-02-18 8:27 ` David Hildenbrand
2020-02-18 15:46 ` Sean Christopherson
2020-02-18 16:02 ` Will Deacon
2020-02-18 16:15 ` Christian Borntraeger
2020-02-18 21:35 ` Sean Christopherson
2020-02-19 8:31 ` David Hildenbrand
2020-02-14 22:26 ` [PATCH v2 05/42] s390/mm: provide memory management functions for protected KVM guests Christian Borntraeger
2020-02-17 10:21 ` David Hildenbrand
2020-02-17 11:28 ` Christian Borntraeger
2020-02-17 12:07 ` David Hildenbrand
2020-02-14 22:26 ` [PATCH v2 06/42] s390/mm: add (non)secure page access exceptions handlers Christian Borntraeger
2020-02-14 22:26 ` Christian Borntraeger [this message]
2020-02-18 16:25 ` [PATCH v2 39/42] example for future extension: mm:gup/writeback: add callbacks for inaccessible pages: error cases Will Deacon
2020-02-18 16:30 ` Christian Borntraeger
2020-02-18 16:33 ` Will Deacon
2020-02-14 22:26 ` [PATCH v2 40/42] example for future extension: mm:gup/writeback: add callbacks for inaccessible pages: source indication Christian Borntraeger
2020-02-17 14:15 ` Ulrich Weigand
2020-02-17 14:38 ` Christian Borntraeger
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