Function fs endpoint files does not have the notion of file position. So switch to stream like functionality. This allows concurrent threads to be blocked in the ffs read/write operations which use ffs_mutex_lock(). The ffs mutex lock deploys interruptible wait. Otherwise, threads are blocking for the mutex lock in __fdget_pos(). For whatever reason, ff the host does not send/receive data for longer time, hung task warnings are observed. Change-Id: I602fa56fb5ed4c8c46e19df68c3335c4b12cae81 Signed-off-by: Pavankumar Kondeti <quic_pkondeti@xxxxxxxxxxx> --- drivers/usb/gadget/function/f_fs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index e20c19a..3c584da 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -614,7 +614,7 @@ static int ffs_ep0_open(struct inode *inode, struct file *file) file->private_data = ffs; ffs_data_opened(ffs); - return 0; + return stream_open(inode, file); } static int ffs_ep0_release(struct inode *inode, struct file *file) @@ -1154,7 +1154,7 @@ ffs_epfile_open(struct inode *inode, struct file *file) file->private_data = epfile; ffs_data_opened(epfile->ffs); - return 0; + return stream_open(inode, file); } static int ffs_aio_cancel(struct kiocb *kiocb) -- 2.7.4
