Re: [PATCH v3] mtd:fix cache_state to avoid writing to bad blocks repeatedly

[Xiaoming Ni]

On 2020/3/30 21:52, Miquel Raynal wrote:
> Hi Xiaoming,
>
> Xiaoming Ni <nixiaoming@xxxxxxxxxx> wrote on Mon, 30 Mar 2020 21:45:25
> +0800:
>
> > The function call process is as follows:
> > 	mtd_blktrans_work()
> > 	  while (1)
> > 	    do_blktrans_request()
> > 	      mtdblock_writesect()
> > 	        do_cached_write()
> > 	          write_cached_data() /*if cache_state is STATE_DIRTY*/
> > 	            erase_write()
> >
> > write_cached_data() returns failure without modifying cache_state
> > and cache_offset. So when do_cached_write() is called again,
> > write_cached_data() will be called again to perform erase_write()
> > on the same cache_offset.
> >
> > But if this cache_offset points to a bad block, erase_write() will
> > always return -EIO. Writing to this mtdblk is equivalent to losing
> > the current data, and repeatedly writing to the bad block.
> >
> > Repeatedly writing a bad block has no real benefits,
> > but brings some negative effects:
> > 1 Lost subsequent data
> > 2 Loss of flash device life
> > 3 erase_write() bad blocks are very time-consuming. For example:
> > 	the function do_erase_oneblock() in chips/cfi_cmdset_0020.c or
> > 	chips/cfi_cmdset_0002.c may take more than 20 seconds to return
> >
> > Therefore, when erase_write() returns -EIO in write_cached_data(),
> > clear cache_state to avoid writing to bad blocks repeatedly.
> >
> > Signed-off-by: Xiaoming Ni <nixiaoming@xxxxxxxxxx>
> > Reviewed-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
> > Cc: stable@xxxxxxxxxxxxxxx
>
> Still missing:
> * Fixes: tag
> * Wrong title prefix

Fixes: 	1da177e4c3f41524e88 "Linux-2.6.12-rc2"

Is it described like this?

Do I need to go to
https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git
to trace back the older commit records?

Thanks
Xiaoming Ni