dmaengine: idxd: make submit failure path consistent on desc freeing

The submission path for dmaengine API does not do descriptor freeing on
failure. Also, with the abort mechanism, the freeing of descriptor happens
when the abort callback is completed. Therefore free descriptor on all
error paths for submission call to make things consistent. Also remove the
double free that would happen on abort in idxd_dma_tx_submit() call.

Fixes: 6b4b87f2c31a ("dmaengine: idxd: fix submission race window")
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/162827146072.3459011.10255348500504659810.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/idxd/dma.c b/drivers/dma/idxd/dma.c
index a195225..5c0a4d8 100644 (file)
--- a/drivers/dma/idxd/dma.c
+++ b/drivers/dma/idxd/dma.c
@@ -149,10 +149,8 @@ static dma_cookie_t idxd_dma_tx_submit(struct dma_async_tx_descriptor *tx)
        cookie = dma_cookie_assign(tx);
 
        rc = idxd_submit_desc(wq, desc);
-       if (rc < 0) {
-               idxd_free_desc(wq, desc);
+       if (rc < 0)
                return rc;
-       }
 
        return cookie;
 }

diff --git a/drivers/dma/idxd/submit.c b/drivers/dma/idxd/submit.c
index 4b514c6..de76fb4 100644 (file)
--- a/drivers/dma/idxd/submit.c
+++ b/drivers/dma/idxd/submit.c
@@ -139,11 +139,15 @@ int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
        void __iomem *portal;
        int rc;
 
-       if (idxd->state != IDXD_DEV_ENABLED)
+       if (idxd->state != IDXD_DEV_ENABLED) {
+               idxd_free_desc(wq, desc);
                return -EIO;
+       }
 
-       if (!percpu_ref_tryget_live(&wq->wq_active))
+       if (!percpu_ref_tryget_live(&wq->wq_active)) {
+               idxd_free_desc(wq, desc);
                return -ENXIO;
+       }
 
        portal = idxd_wq_portal_addr(wq);
 
@@ -175,8 +179,11 @@ int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
                rc = enqcmds(portal, desc->hw);
                if (rc < 0) {
                        percpu_ref_put(&wq->wq_active);
+                       /* abort operation frees the descriptor */
                        if (ie)
                                llist_abort_desc(wq, ie, desc);
+                       else
+                               idxd_free_desc(wq, desc);
                        return rc;
                }
        }