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Date:   Sat,  1 Apr 2023 06:05:08 +0000
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Subject: [PATCH v1 1/2] usb: gadget: f_fs: Fix ffs_epfile_read_iter to handle ITER_UBUF
From:   Sandeep Dhavale <dhavale@google.com>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jens Axboe <axboe@kernel.dk>, Keith Busch <kbusch@kernel.org>
Cc:     Sandeep Dhavale <dhavale@google.com>, kernel-team@android.com,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
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iov_iter for ffs_epfile_read_iter can be ITER_UBUF with io_uring.
In that case dup_iter() does not have to allocate anything and it
can return NULL. ffs_epfile_read_iter treats this as a failure and
returns -ENOMEM. Fix it by checking if iter_is_ubuf().

Fixes: 1e23db450cff ("io_uring: use iter_ubuf for single range imports")
Signed-off-by: Sandeep Dhavale <dhavale@google.com>
---
 drivers/usb/gadget/function/f_fs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 8830847fbf97..a13c946e0663 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -1230,7 +1230,7 @@ static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
 	p->kiocb = kiocb;
 	if (p->aio) {
 		p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
-		if (!p->to_free) {
+		if (!iter_is_ubuf(&p->data) && !p->to_free) {
 			kfree(p);
 			return -ENOMEM;
 		}
-- 
2.40.0.348.gf938b09366-goog