By submitting completed transfers to the system workqueue there is no
guarantee that completion events will be queued up in the correct order,
so if a large bulk transfer is being read with aio the data may arrive
in the wrong order.
Create a single-threaded workqueue for FunctionFS so that completed
requests are passed to userspace in the order in which they complete.
Signed-off-by: John Keeping <john@xxxxxxxxxxxx>
---
drivers/usb/gadget/function/f_fs.c | 10 +++++++++-
drivers/usb/gadget/function/u_fs.h | 1 +
2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index d21874b35cf6..d59d0e890d04 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -780,11 +780,12 @@ static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
struct usb_request *req)
{
struct ffs_io_data *io_data = req->context;
+ struct ffs_data *ffs = io_data->ffs;
ENTER();
INIT_WORK(&io_data->work, ffs_user_copy_worker);
- schedule_work(&io_data->work);
+ queue_work(ffs->io_completion_wq, &io_data->work);
}
static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
@@ -1611,6 +1612,7 @@ static void ffs_data_put(struct ffs_data *ffs)
BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
waitqueue_active(&ffs->ep0req_completion.wait) ||
waitqueue_active(&ffs->wait));
+ destroy_workqueue(ffs->io_completion_wq);
kfree(ffs->dev_name);
kfree(ffs);
}
@@ -1651,6 +1653,12 @@ static struct ffs_data *ffs_data_new(void)
ENTER();
+ ffs->io_completion_wq = create_singlethread_workqueue("ffs-completion");
+ if (!ffs->io_completion_wq) {
+ kfree(ffs);
+ return NULL;
+ }
+
refcount_set(&ffs->ref, 1);
atomic_set(&ffs->opened, 0);
ffs->state = FFS_READ_DESCRIPTORS;
diff --git a/drivers/usb/gadget/function/u_fs.h b/drivers/usb/gadget/function/u_fs.h
index 540f1c48c1a8..79f70ebf85dc 100644
--- a/drivers/usb/gadget/function/u_fs.h
+++ b/drivers/usb/gadget/function/u_fs.h
@@ -279,6 +279,7 @@ struct ffs_data {
} file_perms;
struct eventfd_ctx *ffs_eventfd;
+ struct workqueue_struct *io_completion_wq;
bool no_disconnect;
struct work_struct reset_work;
--
2.12.2.648.g6730d8bc62.dirty
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