Re: [PATCH v4 7/7] mtd: spi-nor: add read loop

Michal Suchanek
2015-08-14T10:08:43Z

On 14 August 2015 at 12:02, Andrew Murray <amurray@embedded-bits.co.uk> wrote:
> On 14 August 2015 at 10:23, Michal Suchanek <hramrach@gmail.com> wrote:
>> mtdblock and ubi do not handle the situation when read returns less data
>> than requested. Loop in spi-nor until buffer is filled or an error is
>> returned.
>>
>> Signed-off-by: Michal Suchanek <hramrach@gmail.com>
>> ---
>> drivers/mtd/spi-nor/spi-nor.c | 20 ++++++++++++++------
>> 1 file changed, 14 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
>> index e0ae9cf..246fac7 100644
>> --- a/drivers/mtd/spi-nor/spi-nor.c
>> +++ b/drivers/mtd/spi-nor/spi-nor.c
>> @@ -738,14 +738,22 @@ static int spi_nor_read(struct mtd_info *mtd, loff_t from, size_t len,
>> if (ret)
>> return ret;
>>
>> - ret = nor->read(nor, from, len, buf);
>> + while (len) {
>> + ret = nor->read(nor, from, len, buf);
>> + if (ret <= 0)
>> + goto read_err;
>> +
>> + BUG_ON(ret > len);
>> + *retlen += ret;
>
> Is *retlen initialized to 0 anywhere?

It's initialized in mtdcore and passed into mtd->_read.

Yes, the interface is really awkward.

int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
u_char *buf)
{
int ret_code;
*retlen = 0;

Thanks

Michal