From: Christoph Hellwig <hch@xxxxxx> Subject: mm/filemap: don't cast ->readpage to filler_t for do_read_cache_page We can just pass a NULL filler and do the right thing inside of do_read_cache_page based on the NULL parameter. Link: http://lkml.kernel.org/r/20190520055731.24538-3-hch@xxxxxx Signed-off-by: Christoph Hellwig <hch@xxxxxx> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> Cc: Sami Tolvanen <samitolvanen@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/pagemap.h | 3 +-- mm/filemap.c | 10 ++++++---- 2 files changed, 7 insertions(+), 6 deletions(-) --- a/include/linux/pagemap.h~mm-dont-cast-readpage-to-filler_t-for-do_read_cache_page +++ a/include/linux/pagemap.h @@ -383,8 +383,7 @@ extern int read_cache_pages(struct addre static inline struct page *read_mapping_page(struct address_space *mapping, pgoff_t index, void *data) { - filler_t *filler = (filler_t *)mapping->a_ops->readpage; - return read_cache_page(mapping, index, filler, data); + return read_cache_page(mapping, index, NULL, data); } /* --- a/mm/filemap.c~mm-dont-cast-readpage-to-filler_t-for-do_read_cache_page +++ a/mm/filemap.c @@ -2825,7 +2825,11 @@ repeat: } filler: - err = filler(data, page); + if (filler) + err = filler(data, page); + else + err = mapping->a_ops->readpage(data, page); + if (err < 0) { put_page(page); return ERR_PTR(err); @@ -2937,9 +2941,7 @@ struct page *read_cache_page_gfp(struct pgoff_t index, gfp_t gfp) { - filler_t *filler = (filler_t *)mapping->a_ops->readpage; - - return do_read_cache_page(mapping, index, filler, NULL, gfp); + return do_read_cache_page(mapping, index, NULL, NULL, gfp); } EXPORT_SYMBOL(read_cache_page_gfp); _
