Convert the fuse filesystem to support the new iov_iter_get_pages() behavior. That routine now invokes pin_user_pages_fast(), which means that such pages must be released via unpin_user_page(), rather than via put_page(). This commit also removes any possibility of kernel pages being handled, in the fuse_get_user_pages() call. Although this may seem like a steep price to pay, Christoph Hellwig actually recommended it a few years ago for nearly the same situation [1]. [1] https://lore.kernel.org/kvm/20190724061750.GA19397@xxxxxxxxxxxxx/ Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx> --- fs/fuse/dev.c | 5 ++++- fs/fuse/file.c | 23 ++++++++--------------- 2 files changed, 12 insertions(+), 16 deletions(-) diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index e1b4a846c90d..a93037c96b89 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -675,7 +675,10 @@ static void fuse_copy_finish(struct fuse_copy_state *cs) flush_dcache_page(cs->pg); set_page_dirty_lock(cs->pg); } - put_page(cs->pg); + if (cs->pipebufs) + put_page(cs->pg); + else + unpin_user_page(cs->pg); } cs->pg = NULL; } diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 94747bac3489..395c2fb613fb 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -619,7 +619,7 @@ static void fuse_release_user_pages(struct fuse_args_pages *ap, for (i = 0; i < ap->num_pages; i++) { if (should_dirty) set_page_dirty_lock(ap->pages[i]); - put_page(ap->pages[i]); + unpin_user_page(ap->pages[i]); } } @@ -1382,20 +1382,13 @@ static int fuse_get_user_pages(struct fuse_args_pages *ap, struct iov_iter *ii, size_t nbytes = 0; /* # bytes already packed in req */ ssize_t ret = 0; - /* Special case for kernel I/O: can copy directly into the buffer */ - if (iov_iter_is_kvec(ii)) { - unsigned long user_addr = fuse_get_user_addr(ii); - size_t frag_size = fuse_get_frag_size(ii, *nbytesp); - - if (write) - ap->args.in_args[1].value = (void *) user_addr; - else - ap->args.out_args[0].value = (void *) user_addr; - - iov_iter_advance(ii, frag_size); - *nbytesp = frag_size; - return 0; - } + /* + * TODO: this warning can eventually be removed. It is just to help + * developers, during a transitional period, while direct IO code is + * moving over to FOLL_PIN pages. + */ + if (WARN_ON_ONCE(!iter_is_iovec(ii))) + return -EOPNOTSUPP; while (nbytes < *nbytesp && ap->num_pages < max_pages) { unsigned npages; -- 2.35.1
