[PATCH] mxs-dcp: Remove mutex_lock from probe

[PATCH] mxs-dcp: Remove mutex_lock from probe

[Fabio Estevam]

From: Fabio Estevam <fabio.estevam@freescale.com>

Remove mutex_lock from probe in order to avoid the following warning:

[    8.526613] Freeing unused kernel memory: 232K (c0683000 - c06bd000)
starting pid 56, tty '': '/etc/rc.d/rcS'
[    9.110314]
[    9.111864] =====================================
[    9.116603] [ BUG: init/1 still has locks held! ]
[    9.121488] 3.15.0-rc4-next-20140509-00001-g319564e #1154 Not tainted
[    9.128071] -------------------------------------
[    9.132825] 1 lock held by init/1:
[    9.136252]  #0:  (global_mutex){+.+.+.}, at: [<c0387d68>] mxs_dcp_probe+0x14
[    9.144196]
[    9.144196] stack backtrace:
[    9.148888] CPU: 0 PID: 1 Comm: init Not tainted 3.15.0-rc4-next-20140509-004
[    9.157610] [<c000da40>] (unwind_backtrace) from [<c000bda4>] (show_stack+0x)
[    9.165595] [<c000bda4>] (show_stack) from [<c00153d4>] (do_fork+0x2c8/0x3cc)
[    9.172921] [<c00153d4>] (do_fork) from [<c0015550>] (sys_vfork+0x20/0x2c)
[    9.179973] [<c0015550>] (sys_vfork) from [<c0009580>] (ret_fast_syscall+0x0)

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
---
 drivers/crypto/mxs-dcp.c | 47 ++++++++++++++++-------------------------------
 1 file changed, 16 insertions(+), 31 deletions(-)

diff --git a/drivers/crypto/mxs-dcp.c b/drivers/crypto/mxs-dcp.c
index 7bbe0ab..f100ee1 100644
--- a/drivers/crypto/mxs-dcp.c
+++ b/drivers/crypto/mxs-dcp.c
@@ -907,60 +907,49 @@ static int mxs_dcp_probe(struct platform_device *pdev)
 	struct resource *iores;
 	int dcp_vmi_irq, dcp_irq;
 
-	mutex_lock(&global_mutex);
 	if (global_sdcp) {
 		dev_err(dev, "Only one DCP instance allowed!\n");
-		ret = -ENODEV;
-		goto err_mutex;
+		return -ENODEV;
 	}
 
 	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	dcp_vmi_irq = platform_get_irq(pdev, 0);
-	if (dcp_vmi_irq < 0) {
-		ret = dcp_vmi_irq;
-		goto err_mutex;
-	}
+	if (dcp_vmi_irq < 0)
+		return dcp_vmi_irq;
 
 	dcp_irq = platform_get_irq(pdev, 1);
-	if (dcp_irq < 0) {
-		ret = dcp_irq;
-		goto err_mutex;
-	}
+	if (dcp_irq < 0)
+		return dcp_irq;
 
 	sdcp = devm_kzalloc(dev, sizeof(*sdcp), GFP_KERNEL);
-	if (!sdcp) {
-		ret = -ENOMEM;
-		goto err_mutex;
-	}
+	if (!sdcp)
+		return -ENOMEM;
 
 	sdcp->dev = dev;
 	sdcp->base = devm_ioremap_resource(dev, iores);
-	if (IS_ERR(sdcp->base)) {
-		ret = PTR_ERR(sdcp->base);
-		goto err_mutex;
-	}
+	if (IS_ERR(sdcp->base))
+		return PTR_ERR(sdcp->base);
+
 
 	ret = devm_request_irq(dev, dcp_vmi_irq, mxs_dcp_irq, 0,
 			       "dcp-vmi-irq", sdcp);
 	if (ret) {
 		dev_err(dev, "Failed to claim DCP VMI IRQ!\n");
-		goto err_mutex;
+		return ret;
 	}
 
 	ret = devm_request_irq(dev, dcp_irq, mxs_dcp_irq, 0,
 			       "dcp-irq", sdcp);
 	if (ret) {
 		dev_err(dev, "Failed to claim DCP IRQ!\n");
-		goto err_mutex;
+		return ret;
 	}
 
 	/* Allocate coherent helper block. */
 	sdcp->coh = devm_kzalloc(dev, sizeof(*sdcp->coh) + DCP_ALIGNMENT,
 				   GFP_KERNEL);
-	if (!sdcp->coh) {
-		ret = -ENOMEM;
-		goto err_mutex;
-	}
+	if (!sdcp->coh)
+		return -ENOMEM;
 
 	/* Re-align the structure so it fits the DCP constraints. */
 	sdcp->coh = PTR_ALIGN(sdcp->coh, DCP_ALIGNMENT);
@@ -968,7 +957,7 @@ static int mxs_dcp_probe(struct platform_device *pdev)
 	/* Restart the DCP block. */
 	ret = stmp_reset_block(sdcp->base);
 	if (ret)
-		goto err_mutex;
+		return ret;
 
 	/* Initialize control register. */
 	writel(MXS_DCP_CTRL_GATHER_RESIDUAL_WRITES |
@@ -1006,8 +995,7 @@ static int mxs_dcp_probe(struct platform_device *pdev)
 						      NULL, "mxs_dcp_chan/sha");
 	if (IS_ERR(sdcp->thread[DCP_CHAN_HASH_SHA])) {
 		dev_err(dev, "Error starting SHA thread!\n");
-		ret = PTR_ERR(sdcp->thread[DCP_CHAN_HASH_SHA]);
-		goto err_mutex;
+		return PTR_ERR(sdcp->thread[DCP_CHAN_HASH_SHA]);
 	}
 
 	sdcp->thread[DCP_CHAN_CRYPTO] = kthread_run(dcp_chan_thread_aes,
@@ -1064,9 +1052,6 @@ err_destroy_aes_thread:
 
 err_destroy_sha_thread:
 	kthread_stop(sdcp->thread[DCP_CHAN_HASH_SHA]);
-
-err_mutex:
-	mutex_unlock(&global_mutex);
 	return ret;
 }
 
-- 
1.8.3.2

Re: [PATCH] mxs-dcp: Remove mutex_lock from probe

[Marek Vasut]

On Monday, May 12, 2014 at 04:35:23 AM, Fabio Estevam wrote:
> From: Fabio Estevam <fabio.estevam@freescale.com>
> 
> Remove mutex_lock from probe in order to avoid the following warning:
> 
> [    8.526613] Freeing unused kernel memory: 232K (c0683000 - c06bd000)
> starting pid 56, tty '': '/etc/rc.d/rcS'
> [    9.110314]
> [    9.111864] =====================================
> [    9.116603] [ BUG: init/1 still has locks held! ]
> [    9.121488] 3.15.0-rc4-next-20140509-00001-g319564e #1154 Not tainted
> [    9.128071] -------------------------------------
> [    9.132825] 1 lock held by init/1:
> [    9.136252]  #0:  (global_mutex){+.+.+.}, at: [<c0387d68>]
> mxs_dcp_probe+0x14 [    9.144196]
> [    9.144196] stack backtrace:
> [    9.148888] CPU: 0 PID: 1 Comm: init Not tainted
> 3.15.0-rc4-next-20140509-004 [    9.157610] [<c000da40>]
> (unwind_backtrace) from [<c000bda4>] (show_stack+0x) [    9.165595]
> [<c000bda4>] (show_stack) from [<c00153d4>] (do_fork+0x2c8/0x3cc) [   
> 9.172921] [<c00153d4>] (do_fork) from [<c0015550>] (sys_vfork+0x20/0x2c) [
>    9.179973] [<c0015550>] (sys_vfork) from [<c0009580>]
> (ret_fast_syscall+0x0)
> 
> Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
> ---
>  drivers/crypto/mxs-dcp.c | 47
> ++++++++++++++++------------------------------- 1 file changed, 16
> insertions(+), 31 deletions(-)

You can also eliminate the DECLARE_MUTEX() for global_mutex now.

Best regards,
Marek Vasut