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| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2025-05-14 20:06:02 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-05-29 12:03:22 +0300 |
| commit | 9b8263cae64a6e51ec643cfcec7042d55f3af348 (patch) | |
| tree | 07460ec525b344d0a388227209734f553df8f73d /include/linux/page-flags.h | |
| parent | cb9a1019a63fe30ed769f2cf4e864c492c3f361d (diff) | |
| download | linux-9b8263cae64a6e51ec643cfcec7042d55f3af348.tar.xz | |
highmem: add folio_test_partial_kmap()
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) <willy@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/page-flags.h')
| -rw-r--r-- | include/linux/page-flags.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index a9244291f506..4e8c6d0511c5 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -573,6 +573,13 @@ FOLIO_FLAG(readahead, FOLIO_HEAD_PAGE) PAGEFLAG_FALSE(HighMem, highmem) #endif +/* Does kmap_local_folio() only allow access to one page of the folio? */ +#ifdef CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP +#define folio_test_partial_kmap(f) true +#else +#define folio_test_partial_kmap(f) folio_test_highmem(f) +#endif + #ifdef CONFIG_SWAP static __always_inline bool folio_test_swapcache(const struct folio *folio) { |