diff --git a/fs/aio.c b/fs/aio.c index aaaaf4d..82c0842 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -167,9 +167,13 @@ struct kioctx { unsigned id; }; +/* + * First field must be the file pointer in all the + * iocb unions! See also 'struct kiocb' in + */ struct fsync_iocb { - struct work_struct work; struct file *file; + struct work_struct work; bool datasync; }; @@ -183,8 +187,15 @@ struct poll_iocb { struct work_struct work; }; +/* + * NOTE! Each of the iocb union members has the file pointer + * as the first entry in their struct definition. So you can + * access the file pointer through any of the sub-structs, + * or directly as just 'ki_filp' in this struct. + */ struct aio_kiocb { union { + struct file *ki_filp; struct kiocb rw; struct fsync_iocb fsync; struct poll_iocb poll; @@ -1060,6 +1071,8 @@ static inline void iocb_put(struct aio_kiocb *iocb) { if (refcount_read(&iocb->ki_refcnt) == 0 || refcount_dec_and_test(&iocb->ki_refcnt)) { + if (iocb->ki_filp) + fput(iocb->ki_filp); percpu_ref_put(&iocb->ki_ctx->reqs); kmem_cache_free(kiocb_cachep, iocb); } @@ -1424,7 +1437,6 @@ static void aio_complete_rw(struct kiocb *kiocb, long res, long res2) file_end_write(kiocb->ki_filp); } - fput(kiocb->ki_filp); aio_complete(iocb, res, res2); } @@ -1432,9 +1444,6 @@ static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb) { int ret; - req->ki_filp = fget(iocb->aio_fildes); - if (unlikely(!req->ki_filp)) - return -EBADF; req->ki_complete = aio_complete_rw; req->private = NULL; req->ki_pos = iocb->aio_offset; @@ -1451,7 +1460,7 @@ static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb) ret = ioprio_check_cap(iocb->aio_reqprio); if (ret) { pr_debug("aio ioprio check cap error: %d\n", ret); - goto out_fput; + return ret; } req->ki_ioprio = iocb->aio_reqprio; @@ -1460,14 +1469,10 @@ static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb) ret = kiocb_set_rw_flags(req, iocb->aio_rw_flags); if (unlikely(ret)) - goto out_fput; + return ret; req->ki_flags &= ~IOCB_HIPRI; /* no one is going to poll for this I/O */ return 0; - -out_fput: - fput(req->ki_filp); - return ret; } static int aio_setup_rw(int rw, const struct iocb *iocb, struct iovec **iovec, @@ -1521,24 +1526,19 @@ static ssize_t aio_read(struct kiocb *req, const struct iocb *iocb, if (ret) return ret; file = req->ki_filp; - - ret = -EBADF; if (unlikely(!(file->f_mode & FMODE_READ))) - goto out_fput; + return -EBADF; ret = -EINVAL; if (unlikely(!file->f_op->read_iter)) - goto out_fput; + return -EINVAL; ret = aio_setup_rw(READ, iocb, &iovec, vectored, compat, &iter); if (ret) - goto out_fput; + 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)); kfree(iovec); -out_fput: - if (unlikely(ret)) - fput(file); return ret; } @@ -1555,16 +1555,14 @@ static ssize_t aio_write(struct kiocb *req, const struct iocb *iocb, return ret; file = req->ki_filp; - ret = -EBADF; if (unlikely(!(file->f_mode & FMODE_WRITE))) - goto out_fput; - ret = -EINVAL; + return -EBADF; if (unlikely(!file->f_op->write_iter)) - goto out_fput; + return -EINVAL; ret = aio_setup_rw(WRITE, iocb, &iovec, vectored, compat, &iter); if (ret) - goto out_fput; + return ret; ret = rw_verify_area(WRITE, file, &req->ki_pos, iov_iter_count(&iter)); if (!ret) { /* @@ -1582,9 +1580,6 @@ static ssize_t aio_write(struct kiocb *req, const struct iocb *iocb, aio_rw_done(req, call_write_iter(file, req, &iter)); } kfree(iovec); -out_fput: - if (unlikely(ret)) - fput(file); return ret; } @@ -1594,7 +1589,6 @@ static void aio_fsync_work(struct work_struct *work) int ret; ret = vfs_fsync(req->file, req->datasync); - fput(req->file); aio_complete(container_of(req, struct aio_kiocb, fsync), ret, 0); } @@ -1605,13 +1599,8 @@ static int aio_fsync(struct fsync_iocb *req, const struct iocb *iocb, iocb->aio_rw_flags)) return -EINVAL; - req->file = fget(iocb->aio_fildes); - if (unlikely(!req->file)) - return -EBADF; - if (unlikely(!req->file->f_op->fsync)) { - fput(req->file); + if (unlikely(!req->file->f_op->fsync)) return -EINVAL; - } req->datasync = datasync; INIT_WORK(&req->work, aio_fsync_work); @@ -1621,10 +1610,7 @@ static int aio_fsync(struct fsync_iocb *req, const struct iocb *iocb, static inline void aio_poll_complete(struct aio_kiocb *iocb, __poll_t mask) { - struct file *file = iocb->poll.file; - aio_complete(iocb, mangle_poll(mask), 0); - fput(file); } static void aio_poll_complete_work(struct work_struct *work) @@ -1743,9 +1729,6 @@ static ssize_t aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb) INIT_WORK(&req->work, aio_poll_complete_work); req->events = demangle_poll(iocb->aio_buf) | EPOLLERR | EPOLLHUP; - req->file = fget(iocb->aio_fildes); - if (unlikely(!req->file)) - return -EBADF; req->head = NULL; req->woken = false; @@ -1788,10 +1771,8 @@ static ssize_t aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb) spin_unlock_irq(&ctx->ctx_lock); out: - if (unlikely(apt.error)) { - fput(req->file); + if (unlikely(apt.error)) return apt.error; - } if (mask) aio_poll_complete(aiocb, mask); @@ -1829,6 +1810,11 @@ static int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb, if (unlikely(!req)) goto out_put_reqs_available; + req->ki_filp = fget(iocb->aio_fildes); + ret = -EBADF; + if (unlikely(!req->ki_filp)) + goto out_put_req; + if (iocb->aio_flags & IOCB_FLAG_RESFD) { /* * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an diff --git a/include/linux/fs.h b/include/linux/fs.h index 29d8e2c..fd423fe 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -304,13 +304,19 @@ enum rw_hint { struct kiocb { struct file *ki_filp; + + /* The 'ki_filp' pointer is shared in a union for aio */ + randomized_struct_fields_start + loff_t ki_pos; void (*ki_complete)(struct kiocb *iocb, long ret, long ret2); void *private; int ki_flags; u16 ki_hint; u16 ki_ioprio; /* See linux/ioprio.h */ -} __randomize_layout; + + randomized_struct_fields_end +}; static inline bool is_sync_kiocb(struct kiocb *kiocb) {