The iomap code was limited to PAGE_SIZE bytes; generalise it to cover an arbitrary-sized folio, and move it to be a common helper.
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]> --- fs/iomap/buffered-io.c | 14 ++------------ include/linux/highmem.h | 38 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 40 insertions(+), 12 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index f72df2babe56..093c4515b22a 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -305,28 +305,18 @@ static int iomap_read_inline_data(const struct iomap_iter *iter, { const struct iomap *iomap = iomap_iter_srcmap(iter); size_t size = i_size_read(iter->inode) - iomap->offset; - size_t poff = offset_in_page(iomap->offset); size_t offset = offset_in_folio(folio, iomap->offset); - void *addr; if (folio_test_uptodate(folio)) return 0; - if (WARN_ON_ONCE(size > PAGE_SIZE - poff)) - return -EIO; - if (WARN_ON_ONCE(size > PAGE_SIZE - - offset_in_page(iomap->inline_data))) - return -EIO; if (WARN_ON_ONCE(size > iomap->length)) return -EIO; if (offset > 0) ifs_alloc(iter->inode, folio, iter->flags); - addr = kmap_local_folio(folio, offset); - memcpy(addr, iomap->inline_data, size); - memset(addr + size, 0, PAGE_SIZE - poff - size); - kunmap_local(addr); - iomap_set_range_uptodate(folio, offset, PAGE_SIZE - poff); + folio_fill_tail(folio, offset, iomap->inline_data, size); + iomap_set_range_uptodate(folio, offset, folio_size(folio) - offset); return 0; } diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 1b81416196dd..0fbb60ffefc9 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -521,6 +521,44 @@ static inline __must_check void *folio_zero_tail(struct folio *folio, return kaddr; } +/** + * folio_fill_tail - Copy some data to a folio and pad with zeroes. + * @folio: The destination folio. + * @offset: The offset into @folio at which to start copying. + * @from: The data to copy. + * @len: How many bytes of data to copy. + * + * This function is most useful for filesystems which support inline data. + * When they want to copy data from the inode into the page cache, this + * function does everything for them. It supports large folios even on + * HIGHMEM configurations. + */ +static inline void folio_fill_tail(struct folio *folio, size_t offset, + const char *from, size_t len) +{ + char *to = kmap_local_folio(folio, offset); + + VM_BUG_ON(offset + len > folio_size(folio)); + + if (folio_test_highmem(folio)) { + size_t max = PAGE_SIZE - offset_in_page(offset); + + while (len > max) { + memcpy(to, from, max); + kunmap_local(to); + len -= max; + from += max; + offset += max; + max = PAGE_SIZE; + to = kmap_local_folio(folio, offset); + } + } + + memcpy(to, from, len); + to = folio_zero_tail(folio, offset, to); + kunmap_local(to); +} + /** * memcpy_from_file_folio - Copy some bytes from a file folio. * @to: The destination buffer. -- 2.42.0
