If we hit the UINT_MAX limit of bio->bi_iter.bi_size and so we are anyway not merging this page in this bio, then it make sense to make same_page also as false before returning.
Without this patch, we hit below WARNING in iomap. This mostly happens with very large memory system and / or after tweaking vm dirty threshold params to delay writeback of dirty data. WARNING: CPU: 18 PID: 5130 at fs/iomap/buffered-io.c:74 iomap_page_release+0x120/0x150 CPU: 18 PID: 5130 Comm: fio Kdump: loaded Tainted: G W 5.8.0-rc3 #6 Call Trace: __remove_mapping+0x154/0x320 (unreliable) iomap_releasepage+0x80/0x180 try_to_release_page+0x94/0xe0 invalidate_inode_page+0xc8/0x110 invalidate_mapping_pages+0x1dc/0x540 generic_fadvise+0x3c8/0x450 xfs_file_fadvise+0x2c/0xe0 [xfs] vfs_fadvise+0x3c/0x60 ksys_fadvise64_64+0x68/0xe0 sys_fadvise64+0x28/0x40 system_call_exception+0xf8/0x1c0 system_call_common+0xf0/0x278 Suggested-by: Christoph Hellwig <h...@infradead.org> Reported-by: Shivaprasad G Bhat <sb...@linux.ibm.com> Signed-off-by: Anju T Sudhakar <a...@linux.vnet.ibm.com> Signed-off-by: Ritesh Harjani <rite...@linux.ibm.com> --- [prev discussion]:- https://patchwork.kernel.org/patch/11723453/ block/bio.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/block/bio.c b/block/bio.c index a7366c02c9b5..675ecd81047b 100644 --- a/block/bio.c +++ b/block/bio.c @@ -877,8 +877,10 @@ bool __bio_try_merge_page(struct bio *bio, struct page *page, struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1]; if (page_is_mergeable(bv, page, len, off, same_page)) { - if (bio->bi_iter.bi_size > UINT_MAX - len) + if (bio->bi_iter.bi_size > UINT_MAX - len) { + *same_page = false; return false; + } bv->bv_len += len; bio->bi_iter.bi_size += len; return true; -- 2.25.4
