fs: don't allow to complete sync iocbs through aio_complete
The AIO interface is fairly complex because it tries to allow
filesystems to always work async and then wakeup a synchronous
caller through aio_complete. It turns out that basically no one
was doing this to avoid the complexity and context switches,
and we've already fixed up the remaining users and can now
get rid of this case.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/aio.c b/fs/aio.c
index 667054c..8ca8df1 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -778,22 +778,6 @@
return 0;
}
-/* wait_on_sync_kiocb:
- * Waits on the given sync kiocb to complete.
- */
-ssize_t wait_on_sync_kiocb(struct kiocb *req)
-{
- while (!req->ki_ctx) {
- set_current_state(TASK_UNINTERRUPTIBLE);
- if (req->ki_ctx)
- break;
- io_schedule();
- }
- __set_current_state(TASK_RUNNING);
- return req->ki_user_data;
-}
-EXPORT_SYMBOL(wait_on_sync_kiocb);
-
/*
* exit_aio: called when the last user of mm goes away. At this point, there is
* no way for any new requests to be submited or any of the io_* syscalls to be
@@ -1025,13 +1009,7 @@
* ref, no other paths have a way to get another ref
* - the sync task helpfully left a reference to itself in the iocb
*/
- if (is_sync_kiocb(iocb)) {
- iocb->ki_user_data = res;
- smp_wmb();
- iocb->ki_ctx = ERR_PTR(-EXDEV);
- wake_up_process(iocb->ki_obj.tsk);
- return;
- }
+ BUG_ON(is_sync_kiocb(iocb));
if (iocb->ki_list.next) {
unsigned long flags;
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index 6f4e659..a36da88 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -52,12 +52,6 @@
struct file *file = iocb->ki_filp;
rc = generic_file_read_iter(iocb, to);
- /*
- * Even though this is a async interface, we need to wait
- * for IO to finish to update atime
- */
- if (-EIOCBQUEUED == rc)
- rc = wait_on_sync_kiocb(iocb);
if (rc >= 0) {
path = ecryptfs_dentry_to_lower_path(file->f_path.dentry);
touch_atime(path);
diff --git a/fs/read_write.c b/fs/read_write.c
index f8b8fc1..76e324e 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -346,9 +346,7 @@
iter->type |= READ;
ret = file->f_op->read_iter(&kiocb, iter);
- if (ret == -EIOCBQUEUED)
- ret = wait_on_sync_kiocb(&kiocb);
-
+ BUG_ON(ret == -EIOCBQUEUED);
if (ret > 0)
*ppos = kiocb.ki_pos;
return ret;
@@ -368,9 +366,7 @@
iter->type |= WRITE;
ret = file->f_op->write_iter(&kiocb, iter);
- if (ret == -EIOCBQUEUED)
- ret = wait_on_sync_kiocb(&kiocb);
-
+ BUG_ON(ret == -EIOCBQUEUED);
if (ret > 0)
*ppos = kiocb.ki_pos;
return ret;
@@ -426,8 +422,7 @@
kiocb.ki_pos = *ppos;
ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos);
- if (-EIOCBQUEUED == ret)
- ret = wait_on_sync_kiocb(&kiocb);
+ BUG_ON(ret == -EIOCBQUEUED);
*ppos = kiocb.ki_pos;
return ret;
}
@@ -446,8 +441,7 @@
iov_iter_init(&iter, READ, &iov, 1, len);
ret = filp->f_op->read_iter(&kiocb, &iter);
- if (-EIOCBQUEUED == ret)
- ret = wait_on_sync_kiocb(&kiocb);
+ BUG_ON(ret == -EIOCBQUEUED);
*ppos = kiocb.ki_pos;
return ret;
}
@@ -508,8 +502,7 @@
kiocb.ki_pos = *ppos;
ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos);
- if (-EIOCBQUEUED == ret)
- ret = wait_on_sync_kiocb(&kiocb);
+ BUG_ON(ret == -EIOCBQUEUED);
*ppos = kiocb.ki_pos;
return ret;
}
@@ -528,8 +521,7 @@
iov_iter_init(&iter, WRITE, &iov, 1, len);
ret = filp->f_op->write_iter(&kiocb, &iter);
- if (-EIOCBQUEUED == ret)
- ret = wait_on_sync_kiocb(&kiocb);
+ BUG_ON(ret == -EIOCBQUEUED);
*ppos = kiocb.ki_pos;
return ret;
}
@@ -716,8 +708,7 @@
iov_iter_init(&iter, rw, iov, nr_segs, len);
ret = fn(&kiocb, &iter);
- if (ret == -EIOCBQUEUED)
- ret = wait_on_sync_kiocb(&kiocb);
+ BUG_ON(ret == -EIOCBQUEUED);
*ppos = kiocb.ki_pos;
return ret;
}
@@ -732,8 +723,7 @@
kiocb.ki_pos = *ppos;
ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos);
- if (ret == -EIOCBQUEUED)
- ret = wait_on_sync_kiocb(&kiocb);
+ BUG_ON(ret == -EIOCBQUEUED);
*ppos = kiocb.ki_pos;
return ret;
}