From: Andrew Morton <akpm@linux-foundation.org>
To: willy@infradead.org,peterx@redhat.com,lukas.bulwahn@gmail.com,kirill.shutemov@linux.intel.com,jgg@ziepe.ca,jgg@nvidia.com,jack@suse.cz,imbrenda@linux.ibm.com,hch@lst.de,david@redhat.com,alex.williamson@redhat.com,aarcange@redhat.com,jhubbard@nvidia.com,akpm@linux-foundation.org,patches@lists.linux.dev,linux-mm@kvack.org,mm-commits@vger.kernel.org,torvalds@linux-foundation.org,akpm@linux-foundation.org
Subject: [patch 2/5] mm/gup: follow_pfn_pte(): -EEXIST cleanup
Date: Fri, 11 Feb 2022 16:28:58 -0800 [thread overview]
Message-ID: <20220212002858.B38A8C340EB@smtp.kernel.org> (raw)
In-Reply-To: <20220211162756.9f8e8baef81183041ccfc16f@linux-foundation.org>
From: John Hubbard <jhubbard@nvidia.com>
Subject: mm/gup: follow_pfn_pte(): -EEXIST cleanup
Remove a quirky special case from follow_pfn_pte(), and adjust its callers
to match. Caller changes include:
__get_user_pages(): Regardless of any FOLL_* flags, get_user_pages() and
its variants should handle PFN-only entries by stopping early, if the
caller expected **pages to be filled in. This makes for a more reliable
API, as compared to the previous approach of skipping over such entries
(and thus leaving them silently unwritten).
move_pages(): squash the -EEXIST error return from follow_page() into
-EFAULT, because -EFAULT is listed in the man page, whereas -EEXIST is
not.
Link: https://lkml.kernel.org/r/20220204020010.68930-3-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Peter Xu <peterx@redhat.com>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
--- a/mm/gup.c~mm-gup-follow_pfn_pte-eexist-cleanup
+++ a/mm/gup.c
@@ -464,10 +464,6 @@ static struct page *no_page_table(struct
static int follow_pfn_pte(struct vm_area_struct *vma, unsigned long address,
pte_t *pte, unsigned int flags)
{
- /* No page to get reference */
- if (flags & (FOLL_GET | FOLL_PIN))
- return -EFAULT;
-
if (flags & FOLL_TOUCH) {
pte_t entry = *pte;
@@ -1205,8 +1201,15 @@ retry:
} else if (PTR_ERR(page) == -EEXIST) {
/*
* Proper page table entry exists, but no corresponding
- * struct page.
+ * struct page. If the caller expects **pages to be
+ * filled in, bail out now, because that can't be done
+ * for this page.
*/
+ if (pages) {
+ ret = PTR_ERR(page);
+ goto out;
+ }
+
goto next_page;
} else if (IS_ERR(page)) {
ret = PTR_ERR(page);
--- a/mm/migrate.c~mm-gup-follow_pfn_pte-eexist-cleanup
+++ a/mm/migrate.c
@@ -1762,6 +1762,13 @@ static int do_pages_move(struct mm_struc
}
/*
+ * The move_pages() man page does not have an -EEXIST choice, so
+ * use -EFAULT instead.
+ */
+ if (err == -EEXIST)
+ err = -EFAULT;
+
+ /*
* If the page is already on the target node (!err), store the
* node, otherwise, store the err.
*/
_
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: willy@infradead.org, peterx@redhat.com, lukas.bulwahn@gmail.com,
kirill.shutemov@linux.intel.com, jgg@ziepe.ca, jgg@nvidia.com,
jack@suse.cz, imbrenda@linux.ibm.com, hch@lst.de,
david@redhat.com, alex.williamson@redhat.com,
aarcange@redhat.com, jhubbard@nvidia.com,
akpm@linux-foundation.org, patches@lists.linux.dev,
linux-mm@kvack.org, mm-commits@vger.kernel.org,
torvalds@linux-foundation.org, akpm@linux-foundation.org
Subject: [patch 2/5] mm/gup: follow_pfn_pte(): -EEXIST cleanup
Date: Fri, 11 Feb 2022 16:28:58 -0800 [thread overview]
Message-ID: <20220212002858.B38A8C340EB@smtp.kernel.org> (raw)
In-Reply-To: <20220211162756.9f8e8baef81183041ccfc16f@linux-foundation.org>
From: John Hubbard <jhubbard@nvidia.com>
Subject: mm/gup: follow_pfn_pte(): -EEXIST cleanup
Remove a quirky special case from follow_pfn_pte(), and adjust its callers
to match. Caller changes include:
__get_user_pages(): Regardless of any FOLL_* flags, get_user_pages() and
its variants should handle PFN-only entries by stopping early, if the
caller expected **pages to be filled in. This makes for a more reliable
API, as compared to the previous approach of skipping over such entries
(and thus leaving them silently unwritten).
move_pages(): squash the -EEXIST error return from follow_page() into
-EFAULT, because -EFAULT is listed in the man page, whereas -EEXIST is
not.
Link: https://lkml.kernel.org/r/20220204020010.68930-3-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Peter Xu <peterx@redhat.com>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
--- a/mm/gup.c~mm-gup-follow_pfn_pte-eexist-cleanup
+++ a/mm/gup.c
@@ -464,10 +464,6 @@ static struct page *no_page_table(struct
static int follow_pfn_pte(struct vm_area_struct *vma, unsigned long address,
pte_t *pte, unsigned int flags)
{
- /* No page to get reference */
- if (flags & (FOLL_GET | FOLL_PIN))
- return -EFAULT;
-
if (flags & FOLL_TOUCH) {
pte_t entry = *pte;
@@ -1205,8 +1201,15 @@ retry:
} else if (PTR_ERR(page) == -EEXIST) {
/*
* Proper page table entry exists, but no corresponding
- * struct page.
+ * struct page. If the caller expects **pages to be
+ * filled in, bail out now, because that can't be done
+ * for this page.
*/
+ if (pages) {
+ ret = PTR_ERR(page);
+ goto out;
+ }
+
goto next_page;
} else if (IS_ERR(page)) {
ret = PTR_ERR(page);
--- a/mm/migrate.c~mm-gup-follow_pfn_pte-eexist-cleanup
+++ a/mm/migrate.c
@@ -1762,6 +1762,13 @@ static int do_pages_move(struct mm_struc
}
/*
+ * The move_pages() man page does not have an -EEXIST choice, so
+ * use -EFAULT instead.
+ */
+ if (err == -EEXIST)
+ err = -EFAULT;
+
+ /*
* If the page is already on the target node (!err), store the
* node, otherwise, store the err.
*/
_
next prev parent reply other threads:[~2022-02-12 0:29 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-12 0:27 incoming Andrew Morton
2022-02-12 0:28 ` [patch 1/5] mm: fix invalid page pointer returned with FOLL_PIN gups Andrew Morton
2022-02-12 0:28 ` Andrew Morton
2022-02-12 0:32 ` Andrew Morton
2022-02-12 0:28 ` Andrew Morton [this message]
2022-02-12 0:28 ` [patch 2/5] mm/gup: follow_pfn_pte(): -EEXIST cleanup Andrew Morton
2022-02-12 0:29 ` [patch 3/5] mm/gup: remove unused pin_user_pages_locked() Andrew Morton
2022-02-12 0:29 ` Andrew Morton
2022-02-12 0:29 ` [patch 4/5] mm: change lookup_node() to use get_user_pages_fast() Andrew Morton
2022-02-12 0:29 ` Andrew Morton
2022-02-12 0:29 ` [patch 5/5] mm/gup: remove unused get_user_pages_locked() Andrew Morton
2022-02-12 0:29 ` Andrew Morton
2022-02-12 0:32 ` [patch 1/5] fs/binfmt_elf: fix PT_LOAD p_align values for loaders Andrew Morton
2022-02-12 0:32 ` Andrew Morton
2022-02-12 0:32 ` [patch 2/5] fs/proc: task_mmu.c: don't read mapcount for migration entry Andrew Morton
2022-02-12 0:32 ` Andrew Morton
2022-02-12 0:32 ` [patch 3/5] mm: vmscan: remove deadlock due to throttling failing to make progress Andrew Morton
2022-02-12 0:32 ` Andrew Morton
2022-02-12 0:32 ` [patch 4/5] mm: memcg: synchronize objcg lists with a dedicated spinlock Andrew Morton
2022-02-12 0:32 ` Andrew Morton
2022-02-12 0:32 ` [patch 5/5] kfence: make test case compatible with run time set sample interval Andrew Morton
2022-02-12 0:32 ` Andrew Morton
2022-02-12 2:02 ` incoming Linus Torvalds
2022-02-12 5:24 ` incoming Andrew Morton
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