[U-Boot] [PATCH] FIX: fat: Provide correct return code from disk_{read|write} to upper layers

[Lukasz Majewski]

Hi Tom,,

> Hi,
> 
> > It is very common that FAT code is using following pattern:
> > if (disk_{read|write}() < 0)
> >         return -1;
> > 
> > Up till now the above code was dead, since disk_{read|write) could
> > only return value >= 0.
> > As a result some errors from medium layer (i.e. eMMC/SD) were not
> > caught.
> > 
> > The above behavior was caused by block_{read|write|erase} declared
> > at struct block_dev_desc (@part.h). It returns unsigned long, where
> > 0 indicates error and > 0 indicates that medium operation was
> > correct.
> > 
> > This patch as error regards 0 returned from block_{read|write|erase}
> > when nr_blocks is grater than zero. Read/Write operation with
> > nr_blocks=0 should return 0 and hence is not considered as an error.
> > 
> > Signed-off-by: Lukasz Majewski <l.majewski at samsung.com>
> 
> Are there any more questions regarding this patch? I'd be more than
> happy if it would be added to v2015.10 :-).

Gentle ping :-)

> 
> > 
> > Test HW: Odroid XU3 - Exynos 5433
> > ---
> >  fs/fat/fat.c       | 11 +++++++++--
> >  fs/fat/fat_write.c | 11 +++++++++--
> >  2 files changed, 18 insertions(+), 4 deletions(-)
> > 
> > diff --git a/fs/fat/fat.c b/fs/fat/fat.c
> > index bccc3e3..d743014 100644
> > --- a/fs/fat/fat.c
> > +++ b/fs/fat/fat.c
> > @@ -45,11 +45,18 @@ static disk_partition_t cur_part_info;
> >  
> >  static int disk_read(__u32 block, __u32 nr_blocks, void *buf)
> >  {
> > +	ulong ret;
> > +
> >  	if (!cur_dev || !cur_dev->block_read)
> >  		return -1;
> >  
> > -	return cur_dev->block_read(cur_dev->dev,
> > -			cur_part_info.start + block, nr_blocks,
> > buf);
> > +	ret = cur_dev->block_read(cur_dev->dev,
> > +				  cur_part_info.start + block,
> > nr_blocks, buf); +
> > +	if (nr_blocks && ret == 0)
> > +		return -1;
> > +
> > +	return ret;
> >  }
> >  
> >  int fat_set_blk_dev(block_dev_desc_t *dev_desc, disk_partition_t
> > *info) diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c
> > index 98b88ad..adb6940 100644
> > --- a/fs/fat/fat_write.c
> > +++ b/fs/fat/fat_write.c
> > @@ -30,6 +30,8 @@ static void uppercase(char *str, int len)
> >  static int total_sector;
> >  static int disk_write(__u32 block, __u32 nr_blocks, void *buf)
> >  {
> > +	ulong ret;
> > +
> >  	if (!cur_dev || !cur_dev->block_write)
> >  		return -1;
> >  
> > @@ -39,8 +41,13 @@ static int disk_write(__u32 block, __u32
> > nr_blocks, void *buf) return -1;
> >  	}
> >  
> > -	return cur_dev->block_write(cur_dev->dev,
> > -			cur_part_info.start + block,
> > nr_blocks,	buf);
> > +	ret = cur_dev->block_write(cur_dev->dev,
> > +				   cur_part_info.start + block,
> > +				   nr_blocks, buf);
> > +	if (nr_blocks && ret == 0)
> > +		return -1;
> > +
> > +	return ret;
> >  }
> >  
> >  /*
> 
> 
> 



-- 
Best regards,

Lukasz Majewski

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