Thread (2 messages) 2 messages, 2 authors, 2021-08-27

Re: linux-next: manual merge of the char-misc tree with Linus' tree

From: Manivannan Sadhasivam <hidden>
Date: 2021-08-27 17:56:07
Also in: lkml
Subsystem: mhi bus, networking [general], qualcomm ipc router (qrtr) driver, the rest · Maintainers: Manivannan Sadhasivam, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds

Possibly related (same subject, not in this thread)

Hi Kalle, Stephen,

On Fri, Aug 27, 2021 at 07:24:49PM +0300, Kalle Valo wrote:
Greg KH [off-list ref] writes:
[...]

I'll explain that in detail below. But do note that I'm not familiar
with the MHI subsystem and the MHI folks really should look at this in
detail to make sure no new bugs are introduced! I did the conflict
resolution myself and at least ath11k works after this resolution.
I wanted to fix this thing before breaking for vacation but ended up responding
to it in the middle.

In my test merge I first used Linus' tree as of today as the baseline.
I first merged net-next and it went without conflicts. After that I
merged char-misc-next and got conflicts in two files:
[...]
quoted hunk ↗ jump to hunk
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index 88dba230f406..b15c5bc37dd4 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -1455,9 +1455,6 @@ int mhi_prepare_channel(struct mhi_controller *mhi_cntrl,
        if (ret)
                goto error_pm_state;
 
-       if (mhi_chan->dir == DMA_FROM_DEVICE)
-               mhi_chan->pre_alloc = !!(flags & MHI_CH_INBOUND_ALLOC_BUFS);
-
        /* Pre-allocate buffer for xfer ring */
        if (mhi_chan->pre_alloc) {
                int nr_el = get_nr_avail_ring_elements(mhi_cntrl,

Greg, does this help? Stephen, do you have any advice how to handle
this?
Sorry, this fix won't work. I've done the conflict resolution in
mhi-conflict-fix [1] branch for reference.

The MHI diffs are below:

diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index fc9196f11cb7d..c01ec2fef02ce 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -193,7 +193,7 @@ int mhi_map_single_no_bb(struct mhi_controller *mhi_cntrl,
 int mhi_map_single_use_bb(struct mhi_controller *mhi_cntrl,
 			  struct mhi_buf_info *buf_info)
 {
-	void *buf = mhi_alloc_coherent(mhi_cntrl, buf_info->len,
+	void *buf = dma_alloc_coherent(mhi_cntrl->cntrl_dev, buf_info->len,
 				       &buf_info->p_addr, GFP_ATOMIC);
 
 	if (!buf)
@@ -220,8 +220,8 @@ void mhi_unmap_single_use_bb(struct mhi_controller *mhi_cntrl,
 	if (buf_info->dir == DMA_FROM_DEVICE)
 		memcpy(buf_info->v_addr, buf_info->bb_addr, buf_info->len);
 
-	mhi_free_coherent(mhi_cntrl, buf_info->len, buf_info->bb_addr,
-			  buf_info->p_addr);
+	dma_free_coherent(mhi_cntrl->cntrl_dev, buf_info->len,
+			  buf_info->bb_addr, buf_info->p_addr);
 }
 
 static int get_nr_avail_ring_elements(struct mhi_controller *mhi_cntrl,
@@ -1430,7 +1430,7 @@ exit_unprepare_channel:
 }
 
 int mhi_prepare_channel(struct mhi_controller *mhi_cntrl,
-			struct mhi_chan *mhi_chan)
+			struct mhi_chan *mhi_chan, unsigned int flags)
 {
 	int ret = 0;
 	struct device *dev = &mhi_chan->mhi_dev->dev;
@@ -1455,6 +1455,9 @@ int mhi_prepare_channel(struct mhi_controller *mhi_cntrl,
 	if (ret)
 		goto error_pm_state;
 
+	if (mhi_chan->dir == DMA_FROM_DEVICE)
+		mhi_chan->pre_alloc = !!(flags & MHI_CH_INBOUND_ALLOC_BUFS);
+
 	/* Pre-allocate buffer for xfer ring */
 	if (mhi_chan->pre_alloc) {
 		int nr_el = get_nr_avail_ring_elements(mhi_cntrl,
@@ -1610,7 +1613,7 @@ void mhi_reset_chan(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan)
 }
 
 /* Move channel to start state */
-int mhi_prepare_for_transfer(struct mhi_device *mhi_dev)
+int mhi_prepare_for_transfer(struct mhi_device *mhi_dev, unsigned int flags)
 {
 	int ret, dir;
 	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
@@ -1621,7 +1624,7 @@ int mhi_prepare_for_transfer(struct mhi_device *mhi_dev)
 		if (!mhi_chan)
 			continue;
 
-		ret = mhi_prepare_channel(mhi_cntrl, mhi_chan);
+		ret = mhi_prepare_channel(mhi_cntrl, mhi_chan, flags);
 		if (ret)
 			goto error_open_chan;
 	}


diff --git a/net/qrtr/mhi.c b/net/qrtr/mhi.c
index fa611678af052..29b4fa3b72abf 100644
--- a/net/qrtr/mhi.c
+++ b/net/qrtr/mhi.c
@@ -79,7 +79,7 @@ static int qcom_mhi_qrtr_probe(struct mhi_device *mhi_dev,
 	int rc;
 
 	/* start channels */
-	rc = mhi_prepare_for_transfer(mhi_dev);
+	rc = mhi_prepare_for_transfer(mhi_dev, MHI_CH_INBOUND_ALLOC_BUFS);
 	if (rc)
 		return rc;

But this can be avoided if the below commit is reverted in char-misc-next:

0092a1e3f763 ("bus: mhi: Add inbound buffers allocation flag")

I won't have any objection to that (the original patch can land in v5.16) and
if Greg prefers that, I can send a quick revert patch.

Please let me know!

NOTE: I haven't tested these two solutions as I'm still on vacation. Kalle,
could you please test them to make sure I haven't missed anything?

Thanks,
Mani

[1] https://git.kernel.org/pub/scm/linux/kernel/git/mani/mhi.git/log/?h=mhi-conflict-fix

-- 
https://patchwork.kernel.org/project/linux-wireless/list/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
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