[PATCH] of: reserved_mem: Restructure call site for dma_contiguous_early_fixup()

[PATCH] of: reserved_mem: Restructure call site for dma_contiguous_early_fixup()

[Oreoluwa Babatunde]

Restructure the call site for dma_contiguous_early_fixup() to
where the reserved_mem nodes are being parsed from the DT so that
dma_mmu_remap[] is populated before dma_contiguous_remap() is called.

Fixes: 8a6e02d0c00e ("of: reserved_mem: Restructure how the reserved memory regions are processed")
Signed-off-by: Oreoluwa Babatunde <oreoluwa.babatunde@oss.qualcomm.com>
---
 drivers/of/of_reserved_mem.c | 14 +++++++++++---
 kernel/dma/contiguous.c      |  2 --
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 77016c0cc296..132d2c66cafc 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -25,6 +25,7 @@
 #include <linux/memblock.h>
 #include <linux/kmemleak.h>
 #include <linux/cma.h>
+#include <linux/dma-map-ops.h>
 
 #include "of_private.h"
 
@@ -175,13 +176,17 @@ static int __init __reserved_mem_reserve_reg(unsigned long node,
 		base = dt_mem_next_cell(dt_root_addr_cells, &prop);
 		size = dt_mem_next_cell(dt_root_size_cells, &prop);
 
-		if (size &&
-		    early_init_dt_reserve_memory(base, size, nomap) == 0)
+		if (size && early_init_dt_reserve_memory(base, size, nomap) == 0) {
+			/* Architecture specific contiguous memory fixup. */
+			if (of_flat_dt_is_compatible(node, "shared-dma-pool"))
+				dma_contiguous_early_fixup(base, size);
+
 			pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
 				uname, &base, (unsigned long)(size / SZ_1M));
-		else
+		} else {
 			pr_err("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n",
 			       uname, &base, (unsigned long)(size / SZ_1M));
+		}
 
 		len -= t_len;
 	}
@@ -472,6 +477,9 @@ static int __init __reserved_mem_alloc_size(unsigned long node, const char *unam
 		       uname, (unsigned long)(size / SZ_1M));
 		return -ENOMEM;
 	}
+	/* Architecture specific contiguous memory fixup. */
+	if (of_flat_dt_is_compatible(node, "shared-dma-pool"))
+		dma_contiguous_early_fixup(base, size);
 
 	/* Save region in the reserved_mem array */
 	fdt_reserved_mem_save_node(node, uname, base, size);
diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
index 8df0dfaaca18..9e5d63efe7c5 100644
--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -480,8 +480,6 @@ static int __init rmem_cma_setup(struct reserved_mem *rmem)
 		pr_err("Reserved memory: unable to setup CMA region\n");
 		return err;
 	}
-	/* Architecture specific contiguous memory fixup. */
-	dma_contiguous_early_fixup(rmem->base, rmem->size);
 
 	if (default_cma)
 		dma_contiguous_default_area = cma;
-- 
2.34.1

Re: [PATCH] of: reserved_mem: Restructure call site for dma_contiguous_early_fixup()

[Robin Murphy]

On 08/07/2025 5:56 pm, Oreoluwa Babatunde wrote:
> Restructure the call site for dma_contiguous_early_fixup() to
> where the reserved_mem nodes are being parsed from the DT so that
> dma_mmu_remap[] is populated before dma_contiguous_remap() is called.
> 
> Fixes: 8a6e02d0c00e ("of: reserved_mem: Restructure how the reserved memory regions are processed")
> Signed-off-by: Oreoluwa Babatunde <oreoluwa.babatunde@oss.qualcomm.com>
> ---
>   drivers/of/of_reserved_mem.c | 14 +++++++++++---
>   kernel/dma/contiguous.c      |  2 --
>   2 files changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
> index 77016c0cc296..132d2c66cafc 100644
> --- a/drivers/of/of_reserved_mem.c
> +++ b/drivers/of/of_reserved_mem.c
> @@ -25,6 +25,7 @@
>   #include <linux/memblock.h>
>   #include <linux/kmemleak.h>
>   #include <linux/cma.h>
> +#include <linux/dma-map-ops.h>
>   
>   #include "of_private.h"
>   
> @@ -175,13 +176,17 @@ static int __init __reserved_mem_reserve_reg(unsigned long node,
>   		base = dt_mem_next_cell(dt_root_addr_cells, &prop);
>   		size = dt_mem_next_cell(dt_root_size_cells, &prop);
>   
> -		if (size &&
> -		    early_init_dt_reserve_memory(base, size, nomap) == 0)
> +		if (size && early_init_dt_reserve_memory(base, size, nomap) == 0) {
> +			/* Architecture specific contiguous memory fixup. */
> +			if (of_flat_dt_is_compatible(node, "shared-dma-pool"))

Surely this is now going to call the fixup for *all* "shared-dma-pool" 
reservations, rather than just the ones which are specifically CMA 
regions? That seems potentially bad in a number of ways.

Thanks,
Robin.

> +				dma_contiguous_early_fixup(base, size);
> +
>   			pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
>   				uname, &base, (unsigned long)(size / SZ_1M));
> -		else
> +		} else {
>   			pr_err("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n",
>   			       uname, &base, (unsigned long)(size / SZ_1M));
> +		}
>   
>   		len -= t_len;
>   	}
> @@ -472,6 +477,9 @@ static int __init __reserved_mem_alloc_size(unsigned long node, const char *unam
>   		       uname, (unsigned long)(size / SZ_1M));
>   		return -ENOMEM;
>   	}
> +	/* Architecture specific contiguous memory fixup. */
> +	if (of_flat_dt_is_compatible(node, "shared-dma-pool"))
> +		dma_contiguous_early_fixup(base, size);
>   
>   	/* Save region in the reserved_mem array */
>   	fdt_reserved_mem_save_node(node, uname, base, size);
> diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
> index 8df0dfaaca18..9e5d63efe7c5 100644
> --- a/kernel/dma/contiguous.c
> +++ b/kernel/dma/contiguous.c
> @@ -480,8 +480,6 @@ static int __init rmem_cma_setup(struct reserved_mem *rmem)
>   		pr_err("Reserved memory: unable to setup CMA region\n");
>   		return err;
>   	}
> -	/* Architecture specific contiguous memory fixup. */
> -	dma_contiguous_early_fixup(rmem->base, rmem->size);
>   
>   	if (default_cma)
>   		dma_contiguous_default_area = cma;

Re: [PATCH] of: reserved_mem: Restructure call site for dma_contiguous_early_fixup()

[Oreoluwa Babatunde]

On 7/8/2025 10:17 AM, Robin Murphy wrote:
> On 08/07/2025 5:56 pm, Oreoluwa Babatunde wrote:
>> Restructure the call site for dma_contiguous_early_fixup() to
>> where the reserved_mem nodes are being parsed from the DT so that
>> dma_mmu_remap[] is populated before dma_contiguous_remap() is called.
>>
>> Fixes: 8a6e02d0c00e ("of: reserved_mem: Restructure how the reserved memory regions are processed")
>> Signed-off-by: Oreoluwa Babatunde <oreoluwa.babatunde@oss.qualcomm.com>
>> ---
>>   drivers/of/of_reserved_mem.c | 14 +++++++++++---
>>   kernel/dma/contiguous.c      |  2 --
>>   2 files changed, 11 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
>> index 77016c0cc296..132d2c66cafc 100644
>> --- a/drivers/of/of_reserved_mem.c
>> +++ b/drivers/of/of_reserved_mem.c
>> @@ -25,6 +25,7 @@
>>   #include <linux/memblock.h>
>>   #include <linux/kmemleak.h>
>>   #include <linux/cma.h>
>> +#include <linux/dma-map-ops.h>
>>     #include "of_private.h"
>>   @@ -175,13 +176,17 @@ static int __init __reserved_mem_reserve_reg(unsigned long node,
>>           base = dt_mem_next_cell(dt_root_addr_cells, &prop);
>>           size = dt_mem_next_cell(dt_root_size_cells, &prop);
>>   -        if (size &&
>> -            early_init_dt_reserve_memory(base, size, nomap) == 0)
>> +        if (size && early_init_dt_reserve_memory(base, size, nomap) == 0) {
>> +            /* Architecture specific contiguous memory fixup. */
>> +            if (of_flat_dt_is_compatible(node, "shared-dma-pool"))
> 
> Surely this is now going to call the fixup for *all* "shared-dma-pool" reservations, rather than just the ones which are specifically CMA regions? That seems potentially bad in a number of ways.
> 
> Thanks,
> Robin.

Hi Robin,

Thanks for pointing that out. I believe if we add a check for
of_get_flat_dt_prop(node, "reusable", NULL) that should help
limit this to only the regions that are meant to be cma.

Please let me know if there's something else that I'm missing.

Thanks,
Oreoluwa

> 
>> +                dma_contiguous_early_fixup(base, size);
>> +
>>               pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
>>                   uname, &base, (unsigned long)(size / SZ_1M));
>> -        else
>> +        } else {
>>               pr_err("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n",
>>                      uname, &base, (unsigned long)(size / SZ_1M));
>> +        }
>>             len -= t_len;
>>       }
>> @@ -472,6 +477,9 @@ static int __init __reserved_mem_alloc_size(unsigned long node, const char *unam
>>                  uname, (unsigned long)(size / SZ_1M));
>>           return -ENOMEM;
>>       }
>> +    /* Architecture specific contiguous memory fixup. */
>> +    if (of_flat_dt_is_compatible(node, "shared-dma-pool"))
>> +        dma_contiguous_early_fixup(base, size);
>>         /* Save region in the reserved_mem array */
>>       fdt_reserved_mem_save_node(node, uname, base, size);
>> diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
>> index 8df0dfaaca18..9e5d63efe7c5 100644
>> --- a/kernel/dma/contiguous.c
>> +++ b/kernel/dma/contiguous.c
>> @@ -480,8 +480,6 @@ static int __init rmem_cma_setup(struct reserved_mem *rmem)
>>           pr_err("Reserved memory: unable to setup CMA region\n");
>>           return err;
>>       }
>> -    /* Architecture specific contiguous memory fixup. */
>> -    dma_contiguous_early_fixup(rmem->base, rmem->size);
>>         if (default_cma)
>>           dma_contiguous_default_area = cma;

Re: [PATCH] of: reserved_mem: Restructure call site for dma_contiguous_early_fixup()

[kernel test robot]

Hi Oreoluwa,

kernel test robot noticed the following build errors:

[auto build test ERROR on robh/for-next]
[also build test ERROR on linus/master v6.16-rc5 next-20250708]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Oreoluwa-Babatunde/of-reserved_mem-Restructure-call-site-for-dma_contiguous_early_fixup/20250709-005858
base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next
patch link:    https://lore.kernel.org/r/20250708165627.845295-1-oreoluwa.babatunde%40oss.qualcomm.com
patch subject: [PATCH] of: reserved_mem: Restructure call site for dma_contiguous_early_fixup()
config: i386-buildonly-randconfig-003-20250709 (https://download.01.org/0day-ci/archive/20250709/202507091614.ZsQ9sH7n-lkp@intel.com/config)
compiler: clang version 20.1.7 (https://github.com/llvm/llvm-project 6146a88f60492b520a36f8f8f3231e15f3cc6082)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250709/202507091614.ZsQ9sH7n-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202507091614.ZsQ9sH7n-lkp@intel.com/

All errors (new ones prefixed by >>):

>> drivers/of/of_reserved_mem.c:182:5: error: call to undeclared function 'dma_contiguous_early_fixup'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     182 |                                 dma_contiguous_early_fixup(base, size);
         |                                 ^
   drivers/of/of_reserved_mem.c:482:3: error: call to undeclared function 'dma_contiguous_early_fixup'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     482 |                 dma_contiguous_early_fixup(base, size);
         |                 ^
   2 errors generated.


vim +/dma_contiguous_early_fixup +182 drivers/of/of_reserved_mem.c

   150	
   151	/*
   152	 * __reserved_mem_reserve_reg() - reserve all memory described in 'reg' property
   153	 */
   154	static int __init __reserved_mem_reserve_reg(unsigned long node,
   155						     const char *uname)
   156	{
   157		int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
   158		phys_addr_t base, size;
   159		int len;
   160		const __be32 *prop;
   161		bool nomap;
   162	
   163		prop = of_get_flat_dt_prop(node, "reg", &len);
   164		if (!prop)
   165			return -ENOENT;
   166	
   167		if (len && len % t_len != 0) {
   168			pr_err("Reserved memory: invalid reg property in '%s', skipping node.\n",
   169			       uname);
   170			return -EINVAL;
   171		}
   172	
   173		nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
   174	
   175		while (len >= t_len) {
   176			base = dt_mem_next_cell(dt_root_addr_cells, &prop);
   177			size = dt_mem_next_cell(dt_root_size_cells, &prop);
   178	
   179			if (size && early_init_dt_reserve_memory(base, size, nomap) == 0) {
   180				/* Architecture specific contiguous memory fixup. */
   181				if (of_flat_dt_is_compatible(node, "shared-dma-pool"))
 > 182					dma_contiguous_early_fixup(base, size);
   183	
   184				pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
   185					uname, &base, (unsigned long)(size / SZ_1M));
   186			} else {
   187				pr_err("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n",
   188				       uname, &base, (unsigned long)(size / SZ_1M));
   189			}
   190	
   191			len -= t_len;
   192		}
   193		return 0;
   194	}
   195	

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