linux-kernel - [PATCH] crypto: ccp - Failure on re-initialization due to duplicate sysfs filename

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Message-Id: <20230109021502.682474-1-koba.ko@canonical.com>
Date:   Mon,  9 Jan 2023 10:15:02 +0800
From:   Koba Ko <koba.ko@...onical.com>
To:     Tom Lendacky <thomas.lendacky@....com>,
        John Allen <john.allen@....com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        "David S. Miller" <davem@...emloft.net>,
        linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org,
        Vladis Dronov <vdronov@...hat.com>
Subject: [PATCH] crypto: ccp - Failure on re-initialization due to duplicate sysfs filename

From: Koba Ko <koba.taiwan@...il.com>

The following warning appears during the CCP module re-initialization:

[  140.965403] sysfs: cannot create duplicate filename
'/devices/pci0000:00/0000:00:07.1/0000:03:00.2/dma/dma0chan0'
[  140.975736] CPU: 0 PID: 388 Comm: kworker/0:2 Kdump: loaded Not
tainted 6.2.0-0.rc2.18.eln124.x86_64 #1
[  140.985185] Hardware name: HPE ProLiant DL325 Gen10/ProLiant DL325
Gen10, BIOS A41 07/17/2020
[  140.993761] Workqueue: events work_for_cpu_fn
[  140.998151] Call Trace:
[  141.000613]  <TASK>
[  141.002726]  dump_stack_lvl+0x33/0x46
[  141.006415]  sysfs_warn_dup.cold+0x17/0x23
[  141.010542]  sysfs_create_dir_ns+0xba/0xd0
[  141.014670]  kobject_add_internal+0xba/0x260
[  141.018970]  kobject_add+0x81/0xb0
[  141.022395]  device_add+0xdc/0x7e0
[  141.025822]  ? complete_all+0x20/0x90
[  141.029510]  __dma_async_device_channel_register+0xc9/0x130
[  141.035119]  dma_async_device_register+0x19e/0x3b0
[  141.039943]  ccp_dmaengine_register+0x334/0x3f0 [ccp]
[  141.045042]  ccp5_init+0x662/0x6a0 [ccp]
[  141.049000]  ? devm_kmalloc+0x40/0xd0
[  141.052688]  ccp_dev_init+0xbb/0xf0 [ccp]
[  141.056732]  ? __pci_set_master+0x56/0xd0
[  141.060768]  sp_init+0x70/0x90 [ccp]
[  141.064377]  sp_pci_probe+0x186/0x1b0 [ccp]
[  141.068596]  local_pci_probe+0x41/0x80
[  141.072374]  work_for_cpu_fn+0x16/0x20
[  141.076145]  process_one_work+0x1c8/0x380
[  141.080181]  worker_thread+0x1ab/0x380
[  141.083953]  ? __pfx_worker_thread+0x10/0x10
[  141.088250]  kthread+0xda/0x100
[  141.091413]  ? __pfx_kthread+0x10/0x10
[  141.095185]  ret_from_fork+0x2c/0x50
[  141.098788]  </TASK>
[  141.100996] kobject_add_internal failed for dma0chan0 with -EEXIST,
don't try to register things with the same name in the same directory.
[  141.113703] ccp 0000:03:00.2: ccp initialization failed

The /dma/dma0chan0 sysfs file is not removed since dma_chan object
has been released in ccp_dma_release() before releasing dma device.
A correct procedure would be: release dma channels first => unregister
dma device => release ccp dma object.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=216888
Fixes: 68dbe80f5b51 ("crypto: ccp - Release dma channels before dmaengine unrgister")
Tested-by: Vladis Dronov <vdronov@...hat.com>
Signed-off-by: Koba Ko <koba.ko@...onical.com>
---
 drivers/crypto/ccp/ccp-dmaengine.c | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/drivers/crypto/ccp/ccp-dmaengine.c b/drivers/crypto/ccp/ccp-dmaengine.c
index 9f753cb4f5f18..b386a7063818b 100644
--- a/drivers/crypto/ccp/ccp-dmaengine.c
+++ b/drivers/crypto/ccp/ccp-dmaengine.c
@@ -642,14 +642,26 @@ static void ccp_dma_release(struct ccp_device *ccp)
 		chan = ccp->ccp_dma_chan + i;
 		dma_chan = &chan->dma_chan;
 
-		if (dma_chan->client_count)
-			dma_release_channel(dma_chan);
-
 		tasklet_kill(&chan->cleanup_tasklet);
 		list_del_rcu(&dma_chan->device_node);
 	}
 }
 
+static void ccp_dma_release_channels(struct ccp_device *ccp)
+{
+	struct ccp_dma_chan *chan;
+	struct dma_chan *dma_chan;
+	unsigned int i;
+
+	for (i = 0; i < ccp->cmd_q_count; i++) {
+		chan = ccp->ccp_dma_chan + i;
+		dma_chan = &chan->dma_chan;
+
+		if (dma_chan->client_count)
+			dma_release_channel(dma_chan);
+	}
+}
+
 int ccp_dmaengine_register(struct ccp_device *ccp)
 {
 	struct ccp_dma_chan *chan;
@@ -770,8 +782,9 @@ void ccp_dmaengine_unregister(struct ccp_device *ccp)
 	if (!dmaengine)
 		return;
 
-	ccp_dma_release(ccp);
+	ccp_dma_release_channels(ccp);
 	dma_async_device_unregister(dma_dev);
+	ccp_dma_release(ccp);
 
 	kmem_cache_destroy(ccp->dma_desc_cache);
 	kmem_cache_destroy(ccp->dma_cmd_cache);
-- 
2.25.1