@@ -316,7 +316,8 @@ static void __mv_xor_slot_cleanup(struct mv_xor_chan *mv_chan)
dma_cookie_t cookie = 0;
int busy = mv_chan_is_busy(mv_chan);
u32 current_desc = mv_chan_get_current_desc(mv_chan);
- int seen_current = 0;
+ int current_cleaned = 0;
+ struct mv_xor_desc *hw_desc;
dev_dbg(mv_chan_to_devp(mv_chan), "%s %d\n", __func__, __LINE__);
dev_dbg(mv_chan_to_devp(mv_chan), "current_desc %x\n", current_desc);
@@ -328,38 +329,57 @@ static void __mv_xor_slot_cleanup(struct mv_xor_chan *mv_chan)
list_for_each_entry_safe(iter, _iter, &mv_chan->chain,
chain_node) {
- prefetch(_iter);
- prefetch(&_iter->async_tx);
- /* do not advance past the current descriptor loaded into the
- * hardware channel, subsequent descriptors are either in
- * process or have not been submitted
- */
- if (seen_current)
- break;
+ /* clean finished descriptors */
+ hw_desc = iter->hw_desc;
+ if (hw_desc->status & XOR_DESC_SUCCESS) {
+ cookie = mv_xor_run_tx_complete_actions(iter, mv_chan,
+ cookie);
- /* stop the search if we reach the current descriptor and the
- * channel is busy
- */
- if (iter->async_tx.phys == current_desc) {
- seen_current = 1;
- if (busy)
+ /* done processing desc, clean slot */
+ mv_xor_clean_slot(iter, mv_chan);
+
+ /* break if we did cleaned the current */
+ if (iter->async_tx.phys == current_desc) {
+ current_cleaned = 1;
+ break;
+ }
+ } else {
+ if (iter->async_tx.phys == current_desc) {
+ current_cleaned = 0;
break;
+ }
}
-
- cookie = mv_xor_run_tx_complete_actions(iter, mv_chan, cookie);
-
- if (mv_xor_clean_slot(iter, mv_chan))
- break;
}
if ((busy == 0) && !list_empty(&mv_chan->chain)) {
- struct mv_xor_desc_slot *chain_head;
- chain_head = list_entry(mv_chan->chain.next,
- struct mv_xor_desc_slot,
- chain_node);
-
- mv_xor_start_new_chain(mv_chan, chain_head);
+ if (current_cleaned) {
+ /*
+ * current descriptor cleaned and removed, run
+ * from list head
+ */
+ iter = list_entry(mv_chan->chain.next,
+ struct mv_xor_desc_slot,
+ chain_node);
+ mv_xor_start_new_chain(mv_chan, iter);
+ } else {
+ if (!list_is_last(&iter->chain_node, &mv_chan->chain)) {
+ /*
+ * descriptors are still waiting after
+ * current, trigger them
+ */
+ iter = list_entry(iter->chain_node.next,
+ struct mv_xor_desc_slot,
+ chain_node);
+ mv_xor_start_new_chain(mv_chan, iter);
+ } else {
+ /*
+ * some descriptors are still waiting
+ * to be cleaned
+ */
+ tasklet_schedule(&mv_chan->irq_tasklet);
+ }
+ }
}
if (cookie > 0)
@@ -33,6 +33,7 @@
#define XOR_OPERATION_MODE_XOR 0
#define XOR_OPERATION_MODE_MEMCPY 2
#define XOR_DESCRIPTOR_SWAP BIT(14)
+#define XOR_DESC_SUCCESS 0x40000000
#define XOR_CURR_DESC(chan) (chan->mmr_high_base + 0x10 + (chan->idx * 4))
#define XOR_NEXT_DESC(chan) (chan->mmr_high_base + 0x00 + (chan->idx * 4))
This is a note to let you know that I have just added a patch titled dmaengine: mv_xor: bug fix for racing condition in descriptors cleanup to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue This patch is scheduled to be released in version 3.16.7-ckt15. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.16.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From 6012c238d287820e2bdd5c772f927d9543d69d02 Mon Sep 17 00:00:00 2001 From: Lior Amsalem <alior@marvell.com> Date: Tue, 26 May 2015 15:07:32 +0200 Subject: dmaengine: mv_xor: bug fix for racing condition in descriptors cleanup commit 9136291f1dbc1d4d1cacd2840fb35f4f3ce16c46 upstream. This patch fixes a bug in the XOR driver where the cleanup function can be called and free descriptors that never been processed by the engine (which result in data errors). The cleanup function will free descriptors based on the ownership bit in the descriptors. Fixes: ff7b04796d98 ("dmaengine: DMA engine driver for Marvell XOR engine") Signed-off-by: Lior Amsalem <alior@marvell.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com> Reviewed-by: Ofer Heifetz <oferh@marvell.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com> [ luis: backported to 3.16: - function rename: mv_xor_slot_cleanup() -> __mv_xor_slot_cleanup() - adjusted context ] Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- drivers/dma/mv_xor.c | 72 +++++++++++++++++++++++++++++++++------------------- drivers/dma/mv_xor.h | 1 + 2 files changed, 47 insertions(+), 26 deletions(-)