* [PATCH] dmaengine: bestcomm: use devm_platform_get_and_ioremap_resource() to simplify code
@ 2026-09-09 23:26 Rosen Penev
2026-09-09 23:34 ` sashiko-bot
2026-09-10 1:47 ` Frank Li
0 siblings, 2 replies; 3+ messages in thread
From: Rosen Penev @ 2026-09-09 23:26 UTC (permalink / raw)
To: dmaengine; +Cc: Vinod Koul, Frank Li, open list
Replace the open-coded resource lookup, request_mem_region, ioremap and
the manual iounmap/release_mem_region cleanup in probe/remove with the
managed devm_platform_get_and_ioremap_resource() helper. This removes the
now-unused error-unmap/release paths and simplifies probing.
Fix a resource size mismatch between allocating and freeing where
request_mem_region() and release_mem_region() hopefully use the same size
but is not guarenteed.
Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
v4: fix subject
v3: reword again
v2: remove Sashiko generated description. Reword description.
drivers/dma/bestcomm/bestcomm.c | 45 ++++++++-------------------------
1 file changed, 10 insertions(+), 35 deletions(-)
diff --git a/drivers/dma/bestcomm/bestcomm.c b/drivers/dma/bestcomm/bestcomm.c
index 432b43520ddc..44ff4a42376b 100644
--- a/drivers/dma/bestcomm/bestcomm.c
+++ b/drivers/dma/bestcomm/bestcomm.c
@@ -13,7 +13,6 @@
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/of.h>
-#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <asm/io.h>
@@ -365,13 +364,19 @@ bcom_engine_cleanup(void)
static int mpc52xx_bcom_probe(struct platform_device *op)
{
struct device_node *ofn_sram;
- struct resource res_bcom;
+ struct resource *res_bcom;
+ void __iomem *regs;
int rv;
/* Inform user we're ok so far */
printk(KERN_INFO "DMA: MPC52xx BestComm driver\n");
+ /* Get, reserve & map io */
+ regs = devm_platform_get_and_ioremap_resource(op, 0, &res_bcom);
+ if (IS_ERR(regs))
+ return PTR_ERR(regs);
+
/* Get the bestcomm node */
of_node_get(op->dev.of_node);
@@ -402,35 +407,13 @@ static int mpc52xx_bcom_probe(struct platform_device *op)
/* Save the node */
bcom_eng->ofnode = op->dev.of_node;
- /* Get, reserve & map io */
- if (of_address_to_resource(op->dev.of_node, 0, &res_bcom)) {
- printk(KERN_ERR DRIVER_NAME ": "
- "Can't get resource\n");
- rv = -EINVAL;
- goto error_sramclean;
- }
-
- if (!request_mem_region(res_bcom.start, resource_size(&res_bcom),
- DRIVER_NAME)) {
- printk(KERN_ERR DRIVER_NAME ": "
- "Can't request registers region\n");
- rv = -EBUSY;
- goto error_sramclean;
- }
-
- bcom_eng->regs_base = res_bcom.start;
- bcom_eng->regs = ioremap(res_bcom.start, sizeof(struct mpc52xx_sdma));
- if (!bcom_eng->regs) {
- printk(KERN_ERR DRIVER_NAME ": "
- "Can't map registers\n");
- rv = -ENOMEM;
- goto error_release;
- }
+ bcom_eng->regs = regs;
+ bcom_eng->regs_base = res_bcom->start;
/* Now, do the real init */
rv = bcom_engine_init();
if (rv)
- goto error_unmap;
+ goto error_sramclean;
/* Done ! */
printk(KERN_INFO "DMA: MPC52xx BestComm engine @%08lx ok !\n",
@@ -439,10 +422,6 @@ static int mpc52xx_bcom_probe(struct platform_device *op)
return 0;
/* Error path */
-error_unmap:
- iounmap(bcom_eng->regs);
-error_release:
- release_mem_region(res_bcom.start, sizeof(struct mpc52xx_sdma));
error_sramclean:
kfree(bcom_eng);
bcom_sram_cleanup();
@@ -463,10 +442,6 @@ static void mpc52xx_bcom_remove(struct platform_device *op)
/* Cleanup SRAM */
bcom_sram_cleanup();
- /* Release regs */
- iounmap(bcom_eng->regs);
- release_mem_region(bcom_eng->regs_base, sizeof(struct mpc52xx_sdma));
-
/* Release the node */
of_node_put(bcom_eng->ofnode);
--
2.55.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] dmaengine: bestcomm: use devm_platform_get_and_ioremap_resource() to simplify code
2026-09-09 23:26 [PATCH] dmaengine: bestcomm: use devm_platform_get_and_ioremap_resource() to simplify code Rosen Penev
@ 2026-09-09 23:34 ` sashiko-bot
2026-09-10 1:47 ` Frank Li
1 sibling, 0 replies; 3+ messages in thread
From: sashiko-bot @ 2026-09-09 23:34 UTC (permalink / raw)
To: Rosen Penev; +Cc: vkoul, dmaengine, Frank.Li
Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
Pre-existing issues:
- [High] Dangling Pointer / Use-After-Free in error path
--
commit fa3bb7a565a9593e1a87078d2bf750faaf572e6d
Author: Rosen Penev <rosenp@gmail.com>
dmaengine: bestcomm: use devm_platform_get_and_ioremap_resource() to simplify code
Replace the open-coded resource lookup, request_mem_region, ioremap and
the manual iounmap/release_mem_region cleanup in probe/remove with the
managed devm_platform_get_and_ioremap_resource() helper. This removes the
now-unused error-unmap/release paths and simplifies probing.
> diff --git a/drivers/dma/bestcomm/bestcomm.c b/drivers/dma/bestcomm/bestcomm.c
> index 432b43520ddc9..44ff4a42376b1 100644
> --- a/drivers/dma/bestcomm/bestcomm.c
> +++ b/drivers/dma/bestcomm/bestcomm.c
[ ... ]
> @@ -439,10 +422,6 @@ static int mpc52xx_bcom_probe(struct platform_device *op)
> return 0;
>
> /* Error path */
> -error_unmap:
> - iounmap(bcom_eng->regs);
> -error_release:
> - release_mem_region(res_bcom.start, sizeof(struct mpc52xx_sdma));
> error_sramclean:
> kfree(bcom_eng);
[Severity: High]
This isn't a bug introduced by this patch, but does this error path leave
a dangling pointer?
When mpc52xx_bcom_probe() fails after allocating memory for the globally
visible bcom_eng pointer, it frees the memory but doesn't reset bcom_eng
to NULL.
If probe fails (e.g., during bcom_engine_init()), the global bcom_eng
will point to freed memory. If dependent drivers load later and call
functions like bcom_task_alloc(), wouldn't they dereference this dangling
pointer?
> bcom_sram_cleanup();
> error_ofput:
> of_node_put(op->dev.of_node);
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260909232623.89321-1-rosenp@gmail.com?part=1
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] dmaengine: bestcomm: use devm_platform_get_and_ioremap_resource() to simplify code
2026-09-09 23:26 [PATCH] dmaengine: bestcomm: use devm_platform_get_and_ioremap_resource() to simplify code Rosen Penev
2026-09-09 23:34 ` sashiko-bot
@ 2026-09-10 1:47 ` Frank Li
1 sibling, 0 replies; 3+ messages in thread
From: Frank Li @ 2026-09-10 1:47 UTC (permalink / raw)
To: Rosen Penev; +Cc: dmaengine, Vinod Koul, Frank Li, open list
On Wed, Sep 09, 2026 at 04:26:23PM -0700, Rosen Penev wrote:
> Replace the open-coded resource lookup, request_mem_region, ioremap and
> the manual iounmap/release_mem_region cleanup in probe/remove with the
> managed devm_platform_get_and_ioremap_resource() helper. This removes the
> now-unused error-unmap/release paths and simplifies probing.
>
> Fix a resource size mismatch between allocating and freeing where
> request_mem_region() and release_mem_region() hopefully use the same size
> but is not guarenteed.
>
> Signed-off-by: Rosen Penev <rosenp@gmail.com>
> ---
Missed v4 at subject.
Reviewed-by: Frank Li <Frank.Li@nxp.com>
> v4: fix subject
> v3: reword again
> v2: remove Sashiko generated description. Reword description.
> drivers/dma/bestcomm/bestcomm.c | 45 ++++++++-------------------------
> 1 file changed, 10 insertions(+), 35 deletions(-)
>
> diff --git a/drivers/dma/bestcomm/bestcomm.c b/drivers/dma/bestcomm/bestcomm.c
> index 432b43520ddc..44ff4a42376b 100644
> --- a/drivers/dma/bestcomm/bestcomm.c
> +++ b/drivers/dma/bestcomm/bestcomm.c
> @@ -13,7 +13,6 @@
> #include <linux/kernel.h>
> #include <linux/slab.h>
> #include <linux/of.h>
> -#include <linux/of_address.h>
> #include <linux/of_irq.h>
> #include <linux/platform_device.h>
> #include <asm/io.h>
> @@ -365,13 +364,19 @@ bcom_engine_cleanup(void)
> static int mpc52xx_bcom_probe(struct platform_device *op)
> {
> struct device_node *ofn_sram;
> - struct resource res_bcom;
> + struct resource *res_bcom;
> + void __iomem *regs;
>
> int rv;
>
> /* Inform user we're ok so far */
> printk(KERN_INFO "DMA: MPC52xx BestComm driver\n");
>
> + /* Get, reserve & map io */
> + regs = devm_platform_get_and_ioremap_resource(op, 0, &res_bcom);
> + if (IS_ERR(regs))
> + return PTR_ERR(regs);
> +
> /* Get the bestcomm node */
> of_node_get(op->dev.of_node);
>
> @@ -402,35 +407,13 @@ static int mpc52xx_bcom_probe(struct platform_device *op)
> /* Save the node */
> bcom_eng->ofnode = op->dev.of_node;
>
> - /* Get, reserve & map io */
> - if (of_address_to_resource(op->dev.of_node, 0, &res_bcom)) {
> - printk(KERN_ERR DRIVER_NAME ": "
> - "Can't get resource\n");
> - rv = -EINVAL;
> - goto error_sramclean;
> - }
> -
> - if (!request_mem_region(res_bcom.start, resource_size(&res_bcom),
> - DRIVER_NAME)) {
> - printk(KERN_ERR DRIVER_NAME ": "
> - "Can't request registers region\n");
> - rv = -EBUSY;
> - goto error_sramclean;
> - }
> -
> - bcom_eng->regs_base = res_bcom.start;
> - bcom_eng->regs = ioremap(res_bcom.start, sizeof(struct mpc52xx_sdma));
> - if (!bcom_eng->regs) {
> - printk(KERN_ERR DRIVER_NAME ": "
> - "Can't map registers\n");
> - rv = -ENOMEM;
> - goto error_release;
> - }
> + bcom_eng->regs = regs;
> + bcom_eng->regs_base = res_bcom->start;
>
> /* Now, do the real init */
> rv = bcom_engine_init();
> if (rv)
> - goto error_unmap;
> + goto error_sramclean;
>
> /* Done ! */
> printk(KERN_INFO "DMA: MPC52xx BestComm engine @%08lx ok !\n",
> @@ -439,10 +422,6 @@ static int mpc52xx_bcom_probe(struct platform_device *op)
> return 0;
>
> /* Error path */
> -error_unmap:
> - iounmap(bcom_eng->regs);
> -error_release:
> - release_mem_region(res_bcom.start, sizeof(struct mpc52xx_sdma));
> error_sramclean:
> kfree(bcom_eng);
> bcom_sram_cleanup();
> @@ -463,10 +442,6 @@ static void mpc52xx_bcom_remove(struct platform_device *op)
> /* Cleanup SRAM */
> bcom_sram_cleanup();
>
> - /* Release regs */
> - iounmap(bcom_eng->regs);
> - release_mem_region(bcom_eng->regs_base, sizeof(struct mpc52xx_sdma));
> -
> /* Release the node */
> of_node_put(bcom_eng->ofnode);
>
> --
> 2.55.0
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2026-09-10 1:47 UTC | newest]
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2026-09-09 23:26 [PATCH] dmaengine: bestcomm: use devm_platform_get_and_ioremap_resource() to simplify code Rosen Penev
2026-09-09 23:34 ` sashiko-bot
2026-09-10 1:47 ` Frank Li
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