Implement a wrapper for aio_read()/write() to allow async IO on files not implementing the iter version of read/write, such as sysfs. This mimics how readv/writev uses non-iter ops in do_loop_readv_writev().
Signed-off-by: Bjorn Andersson <[email protected]> --- fs/aio.c | 52 +++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 45 insertions(+), 7 deletions(-) diff --git a/fs/aio.c b/fs/aio.c index f9f441b59966..0137a1a9bef1 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -1514,12 +1514,44 @@ static inline void aio_rw_done(struct kiocb *req, ssize_t ret) } } +static ssize_t aio_iter_readv_writev(struct file *file, struct kiocb *req, + struct iov_iter *iter, int type) +{ + ssize_t ret = 0; + ssize_t nr; + + while (iov_iter_count(iter)) { + struct iovec iovec = iov_iter_iovec(iter); + + if (type == READ) { + nr = file->f_op->read(file, iovec.iov_base, + iovec.iov_len, &req->ki_pos); + } else { + nr = file->f_op->write(file, iovec.iov_base, + iovec.iov_len, &req->ki_pos); + } + + if (nr < 0) { + ret = nr; + break; + } + + ret += nr; + if (nr != iovec.iov_len) + break; + iov_iter_advance(iter, nr); + } + + return ret; +} + static int aio_read(struct kiocb *req, const struct iocb *iocb, bool vectored, bool compat) { struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; struct iov_iter iter; struct file *file; + ssize_t count; int ret; ret = aio_prep_rw(req, iocb); @@ -1529,15 +1561,18 @@ static int aio_read(struct kiocb *req, const struct iocb *iocb, if (unlikely(!(file->f_mode & FMODE_READ))) return -EBADF; ret = -EINVAL; - if (unlikely(!file->f_op->read_iter)) - return -EINVAL; ret = aio_setup_rw(READ, iocb, &iovec, vectored, compat, &iter); if (ret < 0) return ret; ret = rw_verify_area(READ, file, &req->ki_pos, iov_iter_count(&iter)); - if (!ret) - aio_rw_done(req, call_read_iter(file, req, &iter)); + if (!ret) { + if (likely(file->f_op->read_iter)) + count = call_read_iter(file, req, &iter); + else + count = aio_iter_readv_writev(file, req, &iter, READ); + aio_rw_done(req, count); + } kfree(iovec); return ret; } @@ -1548,6 +1583,7 @@ static int aio_write(struct kiocb *req, const struct iocb *iocb, struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; struct iov_iter iter; struct file *file; + ssize_t count; int ret; ret = aio_prep_rw(req, iocb); @@ -1557,8 +1593,6 @@ static int aio_write(struct kiocb *req, const struct iocb *iocb, if (unlikely(!(file->f_mode & FMODE_WRITE))) return -EBADF; - if (unlikely(!file->f_op->write_iter)) - return -EINVAL; ret = aio_setup_rw(WRITE, iocb, &iovec, vectored, compat, &iter); if (ret < 0) @@ -1577,7 +1611,11 @@ static int aio_write(struct kiocb *req, const struct iocb *iocb, __sb_writers_release(file_inode(file)->i_sb, SB_FREEZE_WRITE); } req->ki_flags |= IOCB_WRITE; - aio_rw_done(req, call_write_iter(file, req, &iter)); + if (likely(file->f_op->write_iter)) + count = call_write_iter(file, req, &iter); + else + count = aio_iter_readv_writev(file, req, &iter, WRITE); + aio_rw_done(req, count); } kfree(iovec); return ret; -- 2.18.0
