On 2/20/19 3:58 PM, Ming Lei wrote: > On Mon, Feb 11, 2019 at 12:00:41PM -0700, Jens Axboe wrote: >> For an ITER_BVEC, we can just iterate the iov and add the pages >> to the bio directly. This requires that the caller doesn't releases >> the pages on IO completion, we add a BIO_NO_PAGE_REF flag for that. >> >> The current two callers of bio_iov_iter_get_pages() are updated to >> check if they need to release pages on completion. This makes them >> work with bvecs that contain kernel mapped pages already. >> >> Reviewed-by: Hannes Reinecke <[email protected]> >> Reviewed-by: Christoph Hellwig <[email protected]> >> Signed-off-by: Jens Axboe <[email protected]> >> --- >> block/bio.c | 59 ++++++++++++++++++++++++++++++++------- >> fs/block_dev.c | 5 ++-- >> fs/iomap.c | 5 ++-- >> include/linux/blk_types.h | 1 + >> 4 files changed, 56 insertions(+), 14 deletions(-) >> >> diff --git a/block/bio.c b/block/bio.c >> index 4db1008309ed..330df572cfb8 100644 >> --- a/block/bio.c >> +++ b/block/bio.c >> @@ -828,6 +828,23 @@ int bio_add_page(struct bio *bio, struct page *page, >> } >> EXPORT_SYMBOL(bio_add_page); >> >> +static int __bio_iov_bvec_add_pages(struct bio *bio, struct iov_iter *iter) >> +{ >> + const struct bio_vec *bv = iter->bvec; >> + unsigned int len; >> + size_t size; >> + >> + len = min_t(size_t, bv->bv_len, iter->count); >> + size = bio_add_page(bio, bv->bv_page, len, >> + bv->bv_offset + iter->iov_offset); > > iter->iov_offset needs to be subtracted from 'len', looks > the following delta change[1] is required, otherwise memory corruption > can be observed when running xfstests over loop/dio.
Thanks, I folded this in. -- Jens Axboe
