kernel/linux.git/include/linux/highmem.h, branch v6.6.132

highmem: add folio_test_partial_kmap()

2025-06-04T12:42:21+00:00

commit 97dfbbd135cb5e4426f37ca53a8fa87eaaa4e376 upstream. In commit c749d9b7ebbc ("iov_iter: fix copy_page_from_iter_atomic() if KMAP_LOCAL_FORCE_MAP"), Hugh correctly noted that if KMAP_LOCAL_FORCE_MAP is enabled, we must limit ourselves to PAGE_SIZE bytes per call to kmap_local(). The same problem exists in memcpy_from_folio(), memcpy_to_folio(), folio_zero_tail(), folio_fill_tail() and memcpy_from_file_folio(), so add folio_test_partial_kmap() to do this more succinctly. Link: https://lkml.kernel.org/r/20250514170607.3000994-2-willy@infradead.org Fixes: 00cdf76012ab ("mm: add memcpy_from_file_folio()") Signed-off-by: Matthew Wilcox (Oracle) Cc: Al Viro Cc: Hugh Dickins Cc: Signed-off-by: Andrew Morton Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Greg Kroah-Hartman

highmem: fix a memory copy problem in memcpy_from_folio

2023-12-13T17:45:21+00:00

commit 73424d00dc63ba681856e06cfb0a5abbdb62e2b5 upstream. Clang static checker complains that value stored to 'from' is never read. And memcpy_from_folio() only copy the last chunk memory from folio to destination. Use 'to += chunk' to replace 'from += chunk' to fix this typo problem. Link: https://lkml.kernel.org/r/20231130034017.1210429-1-suhui@nfschina.com Fixes: b23d03ef7af5 ("highmem: add memcpy_to_folio() and memcpy_from_folio()") Signed-off-by: Su Hui Reviewed-by: Matthew Wilcox (Oracle) Cc: Ira Weiny Cc: Jiaqi Yan Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Peter Collingbourne Cc: Tom Rix Cc: Tony Luck Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

highmem: add memcpy_to_folio() and memcpy_from_folio()

2023-08-18T17:12:29+00:00

Patch series "More filesystem folio conversions for 6.6". Remove the only spots in affs which actually use a struct page; there are a few places where one is mentioned, but it's part of the interface. The rest of this is removing the remaining calls to set_bh_page(), and then removing the function before any new users show up. This patch (of 7): These are the folio equivalent of memcpy_to_page() and memcpy_from_page(). [agruenba@redhat.com: use correct chunk size in memcpy()] Link: https://lkml.kernel.org/r/20230802144354.1023099-1-agruenba@redhat.com Link: https://lkml.kernel.org/r/20230713035512.4139457-1-willy@infradead.org Link: https://lkml.kernel.org/r/20230713035512.4139457-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: David Sterba Cc: Jan Kara Cc: Konstantin Komarov Cc: Pankaj Raghav Cc: "Theodore Ts'o" Cc: Alexander Viro Cc: Christian Brauner Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Tom Rix Cc: Andreas Gruenbacher Signed-off-by: Andrew Morton

highmem: Rename put_and_unmap_page() to unmap_and_put_page()

2023-06-05T11:51:00+00:00

With commit 849ad04cf562a ("new helper: put_and_unmap_page()"), Al Viro introduced the put_and_unmap_page() to use in those many places where we have a common pattern consisting of calls to kunmap_local() + put_page(). Obviously, first we unmap and then we put pages. Instead, the original name of this helper seems to imply that we first put and then unmap. Therefore, rename the helper and change the only known upstreamed user (i.e., fs/sysv) before this helper enters common use and might become difficult to find all call sites and instead easy to break the builds. Cc: Al Viro Signed-off-by: Fabio M. De Francesco Reviewed-by: Eric Biggers Message-Id: <20230602103307.5637-1-fmdefrancesco@gmail.com> Signed-off-by: Christian Brauner

mm/hwpoison: introduce copy_mc_highpage

2023-04-18T23:29:51+00:00

Similar to how copy_mc_user_highpage is implemented for copy_user_highpage on #MC supported architecture, introduce the #MC handled version of copy_highpage. This helper has immediate usage when khugepaged wants to copy file-backed memory pages and tolerate #MC. Link: https://lkml.kernel.org/r/20230329151121.949896-3-jiaqiyan@google.com Signed-off-by: Jiaqi Yan Reviewed-by: Yang Shi Cc: David Stevens Cc: Hugh Dickins Cc: Kefeng Wang Cc: Kirill A. Shutemov Cc: "Kirill A. Shutemov" Cc: Miaohe Lin Cc: Naoya Horiguchi Cc: Oscar Salvador Cc: Tong Tiangen Cc: Tony Luck Signed-off-by: Andrew Morton

kasan: call clear_page with a match-all tag instead of changing page tag

2023-03-28T23:20:09+00:00

Instead of changing the page's tag solely in order to obtain a pointer with a match-all tag and then changing it back again, just convert the pointer that we get from kmap_atomic() into one with a match-all tag before passing it to clear_page(). On a certain microarchitecture, this has been observed to cause a measurable improvement in microbenchmark performance, presumably as a result of being able to avoid the atomic operations on the page tag. Link: https://lkml.kernel.org/r/20230216195924.3287772-1-pcc@google.com Signed-off-by: Peter Collingbourne Link: https://linux-review.googlesource.com/id/I0249822cc29097ca7a04ad48e8eb14871f80e711 Reviewed-by: Andrey Konovalov Reviewed-by: Catalin Marinas Cc: Andrey Ryabinin Cc: Evgenii Stepanov Cc: Peter Collingbourne Cc: Vincenzo Frascino Cc: Will Deacon Signed-off-by: Andrew Morton

new helper: put_and_unmap_page()

2023-03-07T06:50:53+00:00

kunmap_local() + put_page(), as done by e.g. ext2 directory handling. Signed-off-by: Al Viro

mm: fix memcpy_from_file_folio() integer underflow

2023-02-10T00:51:30+00:00

If we have a HIGHMEM system with a large folio, 'offset' may be larger than PAGE_SIZE, and so min_t will cap at 'len' instead of the intended end-of-page. That can overflow into the next page which is likely to be unmapped and fault, but could theoretically copy the wrong data. Link: https://lkml.kernel.org/r/Y919vmSrtAgsf6K3@casper.infradead.org Fixes: 00cdf76012ab ("mm: add memcpy_from_file_folio()") Signed-off-by: Matthew Wilcox (Oracle) Cc: "Fabio M. De Francesco" Cc: Ira Weiny Signed-off-by: Andrew Morton

mm: add memcpy_from_file_folio()

2023-02-03T06:33:34+00:00

This is the equivalent of memcpy_from_page(). It differs in that it takes the position in a file instead of offset in a folio, it accepts the total number of bytes to be copied (instead of the number of bytes to be copied from this folio) and it returns how many bytes were copied from the folio, rather than making the caller calculate that and then checking if the caller got it right. [akpm@linux-foundation.org: fix typo in comment] Link: https://lkml.kernel.org/r/20230126201552.1681588-1-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: "Fabio M. De Francesco" Cc: Ira Weiny Signed-off-by: Andrew Morton

mm: add vma_alloc_zeroed_movable_folio()

2023-02-03T06:33:18+00:00

Replace alloc_zeroed_user_highpage_movable(). The main difference is returning a folio containing a single page instead of returning the page, but take the opportunity to rename the function to match other allocation functions a little better and rewrite the documentation to place more emphasis on the zeroing rather than the highmem aspect. Link: https://lkml.kernel.org/r/20230116191813.2145215-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Zi Yan Signed-off-by: Andrew Morton