[U-Boot] [PATCH please test] fs/fat: reduce stack usage for SPL

[U-Boot] [PATCH please test] fs/fat: reduce stack usage for SPL

[Rob Clark]

It seems like stack usage is a problem for SPL builds.  So move itrblock
off the stack.

Please test this and see if it helps w/ current issues with SPL builds.
Long term, I'm not sure if it is better to do this conditional on SPL
builds, or move to malloc()?  At any rate, if this fixes SPL builds it
should be a perfectly ok short term solution.

Signed-off-by: Rob Clark <robdclark@gmail.com>
---
 fs/fat/fat.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/fs/fat/fat.c b/fs/fat/fat.c
index f0284398b4..93140c9bcb 100644
--- a/fs/fat/fat.c
+++ b/fs/fat/fat.c
@@ -1031,10 +1031,12 @@ int file_fat_detectfs(void)
 	return 0;
 }
 
+static fat_itr itrblock;
+
 int fat_exists(const char *filename)
 {
 	fsdata fsdata;
-	fat_itr itrblock, *itr = &itrblock;
+	fat_itr *itr = &itrblock;
 	int ret;
 
 	ret = fat_itr_root(itr, &fsdata);
@@ -1049,7 +1051,7 @@ int fat_exists(const char *filename)
 int fat_size(const char *filename, loff_t *size)
 {
 	fsdata fsdata;
-	fat_itr itrblock, *itr = &itrblock;
+	fat_itr *itr = &itrblock;
 	int ret;
 
 	ret = fat_itr_root(itr, &fsdata);
@@ -1081,7 +1083,7 @@ int file_fat_read_at(const char *filename, loff_t pos, void *buffer,
 		     loff_t maxsize, loff_t *actread)
 {
 	fsdata fsdata;
-	fat_itr itrblock, *itr = &itrblock;
+	fat_itr *itr = &itrblock;
 	int ret;
 
 	ret = fat_itr_root(itr, &fsdata);
-- 
2.13.5

[U-Boot] [PATCH please test] fs/fat: reduce stack usage for SPL

[Tom Rini]

On Sun, Sep 17, 2017 at 09:38:04AM -0400, Rob Clark wrote:

> It seems like stack usage is a problem for SPL builds.  So move itrblock
> off the stack.
> 
> Please test this and see if it helps w/ current issues with SPL builds.
> Long term, I'm not sure if it is better to do this conditional on SPL
> builds, or move to malloc()?  At any rate, if this fixes SPL builds it
> should be a perfectly ok short term solution.
> 
> Signed-off-by: Rob Clark <robdclark@gmail.com>

Tested-by: Tom Rini <trini@konsulko.com>

Note that malloc would also be fine as we already have a dependency on
malloc, that's just not (but should be!) expressed in Kconfig, for FAT
support already.  Thanks!

-- 
Tom
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[U-Boot] [PATCH please test] fs/fat: reduce stack usage for SPL

[Adam Ford]

On Sun, Sep 17, 2017 at 8:42 AM, Tom Rini <trini@konsulko.com> wrote:
> On Sun, Sep 17, 2017 at 09:38:04AM -0400, Rob Clark wrote:
>
>> It seems like stack usage is a problem for SPL builds.  So move itrblock
>> off the stack.
>>
>> Please test this and see if it helps w/ current issues with SPL builds.
>> Long term, I'm not sure if it is better to do this conditional on SPL
>> builds, or move to malloc()?  At any rate, if this fixes SPL builds it
>> should be a perfectly ok short term solution.
>>
>> Signed-off-by: Rob Clark <robdclark@gmail.com>
>
> Tested-by: Tom Rini <trini@konsulko.com>
>

This fixed the problem on the am3517-evm.  Thank you,

Tested-by: Adam Ford <aford173@gmail.com>

> Note that malloc would also be fine as we already have a dependency on
> malloc, that's just not (but should be!) expressed in Kconfig, for FAT
> support already.  Thanks!
>
> --
> Tom

[U-Boot] [PATCHv2] fs/fat: Reduce stack usage

[Tom Rini]

We have limited stack in SPL builds.  Drop itrblock and move to
malloc/free of itr to move this off of the stack.  As part of this fix a
double-free issue in fat_size().

Signed-off-by: Tom Rini <trini@konsulko.com>
---
Rework to use malloc/free as moving this to a global overflows some SH
targets.

 fs/fat/fat.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/fs/fat/fat.c b/fs/fat/fat.c
index f0284398b41d..36a309c73c27 100644
--- a/fs/fat/fat.c
+++ b/fs/fat/fat.c
@@ -1034,24 +1034,27 @@ int file_fat_detectfs(void)
 int fat_exists(const char *filename)
 {
 	fsdata fsdata;
-	fat_itr itrblock, *itr = &itrblock;
+	fat_itr *itr;
 	int ret;
 
+	itr = malloc(sizeof(fat_itr));
 	ret = fat_itr_root(itr, &fsdata);
 	if (ret)
 		return 0;
 
 	ret = fat_itr_resolve(itr, filename, TYPE_ANY);
 	free(fsdata.fatbuf);
+	free(itr);
 	return ret == 0;
 }
 
 int fat_size(const char *filename, loff_t *size)
 {
 	fsdata fsdata;
-	fat_itr itrblock, *itr = &itrblock;
+	fat_itr *itr;
 	int ret;
 
+	itr = malloc(sizeof(fat_itr));
 	ret = fat_itr_root(itr, &fsdata);
 	if (ret)
 		return ret;
@@ -1072,8 +1075,9 @@ int fat_size(const char *filename, loff_t *size)
 	}
 
 	*size = FAT2CPU32(itr->dent->size);
-out:
 	free(fsdata.fatbuf);
+out:
+	free(itr);
 	return ret;
 }
 
@@ -1081,9 +1085,10 @@ int file_fat_read_at(const char *filename, loff_t pos, void *buffer,
 		     loff_t maxsize, loff_t *actread)
 {
 	fsdata fsdata;
-	fat_itr itrblock, *itr = &itrblock;
+	fat_itr *itr;
 	int ret;
 
+	itr = malloc(sizeof(fat_itr));
 	ret = fat_itr_root(itr, &fsdata);
 	if (ret)
 		return ret;
@@ -1097,6 +1102,7 @@ int file_fat_read_at(const char *filename, loff_t pos, void *buffer,
 
 out:
 	free(fsdata.fatbuf);
+	free(itr);
 	return ret;
 }
 
-- 
1.9.1

[U-Boot] [PATCHv2] fs/fat: Reduce stack usage

[Tom Rini]

On Fri, Sep 22, 2017 at 09:02:09AM -0400, Tom Rini wrote:

> We have limited stack in SPL builds.  Drop itrblock and move to
> malloc/free of itr to move this off of the stack.  As part of this fix a
> double-free issue in fat_size().
> 
> Signed-off-by: Tom Rini <trini@konsulko.com>

Applied to u-boot/master, thanks!

-- 
Tom
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