Instead of bailing when fences have already been installed on the
DMABUF, wait for them (with a timeout) when doing a blocking operation.
This fixes the issue where userspace would submit a DMABUF with fences
already installed, with the (correct) expectation that it would just
work.
Fixes: 7b07a2a7ca02 ("usb: gadget: functionfs: Add DMABUF import interface")
Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
---
drivers/usb/gadget/function/f_fs.c | 23 ++++++++++++-----------
1 file changed, 12 insertions(+), 11 deletions(-)
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 70e8532127ad..f855f1fc8e5e 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -46,6 +46,8 @@
#define FUNCTIONFS_MAGIC 0xa647361 /* Chosen by a honest dice roll ;) */
+#define DMABUF_ENQUEUE_TIMEOUT_MS 5000
+
MODULE_IMPORT_NS(DMA_BUF);
/* Reference counter handling */
@@ -1580,9 +1582,11 @@ static int ffs_dmabuf_transfer(struct file *file,
struct usb_request *usb_req;
enum dma_resv_usage resv_dir;
struct dma_buf *dmabuf;
+ unsigned long timeout;
struct ffs_ep *ep;
bool cookie;
u32 seqno;
+ long retl;
int ret;
if (req->flags & ~USB_FFS_DMABUF_TRANSFER_MASK)
@@ -1616,17 +1620,14 @@ static int ffs_dmabuf_transfer(struct file *file,
goto err_attachment_put;
/* Make sure we don't have writers */
- if (!dma_resv_test_signaled(dmabuf->resv, DMA_RESV_USAGE_WRITE)) {
- pr_vdebug("FFS WRITE fence is not signaled\n");
- ret = -EBUSY;
- goto err_resv_unlock;
- }
-
- /* If we're writing to the DMABUF, make sure we don't have readers */
- if (epfile->in &&
- !dma_resv_test_signaled(dmabuf->resv, DMA_RESV_USAGE_READ)) {
- pr_vdebug("FFS READ fence is not signaled\n");
- ret = -EBUSY;
+ timeout = nonblock ? 0 : msecs_to_jiffies(DMABUF_ENQUEUE_TIMEOUT_MS);
+ retl = dma_resv_wait_timeout(dmabuf->resv,
+ dma_resv_usage_rw(epfile->in),
+ true, timeout);
+ if (retl == 0)
+ retl = -EBUSY;
+ if (retl < 0) {
+ ret = (int)retl;
goto err_resv_unlock;
}
--
2.43.0
