Hi Artem: Sorry to interrupt your busy life. As you said in previous mail, I send my patch separately without quoting this e-mail. And I have send to you, but I never get your reply. I am very confuse, no sure if is there anything wrong at the patch I send to you. Can you help explain to me? Thanks
-----Original Message----- From: Artem Bityutskiy [mailto:dedeki...@gmail.com] Sent: Friday, November 01, 2013 4:58 PM To: Qi Wang 王起 (qiwang) Cc: linux-...@lists.infradead.org; Adrian Hunter; linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] MTD: UBI: try to avoid program data to NOR flash after erasure interrupted Hi, could you please re-send your patch separately, without quoting any parts of this conversation, so that I could use 'git am'. Your patch also contains trailing white-spaces, please, get rid of them in the next submission. Also, could you please clearly state whether you have tested this patch on a real NOR flash or not. If yes, then could you share the chip vendor/type information? On Thu, 2013-10-31 at 04:07 +0000, Qi Wang 王起 (qiwang) wrote: > --- a/drivers/mtd/ubi/io.c > +++ b/drivers/mtd/ubi/io.c > @@ -499,59 +499,44 @@ static int nor_erase_prepare(struct ubi_device *ubi, > int pnum) > size_t written; > loff_t addr; > uint32_t data = 0; > - /* > - * Note, we cannot generally define VID header buffers on stack, > - * because of the way we deal with these buffers (see the header > - * comment in this file). But we know this is a NOR-specific piece of > - * code, so we can do this. But yes, this is error-prone and we should > - * (pre-)allocate VID header buffer instead. > - */ Please, do not remove this comment. > struct ubi_vid_hdr vid_hdr; > + struct ubi_ec_hdr ec_hdr; To make it obvious what the above big comment talks about, could you please define 'struct ubi_ec_hdr ec_hdr' above that big comment. Otherwise looks good to me, thank you! > My Comments for above changing: > 1. > - /* > - * Note, we cannot generally define VID header buffers on stack, > - * because of the way we deal with these buffers (see the header > - * comment in this file). But we know this is a NOR-specific > piece of > - * code, so we can do this. But yes, this is error-prone and we > should > - * (pre-)allocate VID header buffer instead. > - */ > I remove above comment, because I pre-allocate VID header and EC header > together. > So I think no need to emphasize VID header buffers cannot be on stack. > (Maybe my understanding about this comment is error, if so, please > correct me) The problem is that some functions in io.c can read or write _beyond_ sizeof(struct ubi_vid_hdr), but this is only relevant to NAND, not for NOR, and the code you change is NOR-only. This is why that comment is there, and I'd like to keep it. > 2. > why use > "if (err != UBI_IO_BAD_HDR_EBADMSG && err != UBI_IO_BAD_HDR && err != > UBI_IO_FF)" > but not > "if (!err)" > to judge if need to program '0' to invalid this block. > > In case err == UBI_IO_FF_BITFLIPS, err == UBI_IO_BITFLIPS or unexpected > value return > from read function, I think UBI still need to invalid this block for > above mentioned > condition. So I use > "if (err != UBI_IO_BAD_HDR_EBADMSG && err != UBI_IO_BAD_HDR && err != > UBI_IO_FF)" > to judge. In case of UBI_IO_FF (all FFs) UBI will erase the eraseblock before using it anyway, so invalidation is not necessary. Thanks! -- Best Regards, Artem Bityutskiy
