From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752248AbcHLWhI (ORCPT ); Fri, 12 Aug 2016 18:37:08 -0400 Received: from down.free-electrons.com ([37.187.137.238]:37968 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751154AbcHLWhH (ORCPT ); Fri, 12 Aug 2016 18:37:07 -0400 Date: Sat, 13 Aug 2016 00:37:03 +0200 From: Boris Brezillon To: Kyle Roeschley Cc: richard@nod.at, dwmw2@infradead.org, computersforpeace@gmail.com, beanhuo@micron.com, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, nathan.sullivan@ni.com, xander.huff@ni.com, peterpansjtu@gmail.com Subject: Re: [PATCH v7 1/2] mtd: nand_bbt: Move BBT block selection logic out of write_bbt() Message-ID: <20160813003703.4e86c042@bbrezillon> In-Reply-To: <1471039103-6745-1-git-send-email-kyle.roeschley@ni.com> References: <1471039103-6745-1-git-send-email-kyle.roeschley@ni.com> Organization: Free Electrons X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 12 Aug 2016 16:58:22 -0500 Kyle Roeschley wrote: > From: Boris Brezillon > > This clarifies the write_bbt() by removing the write label and > clarifying the error/exit path. > > Signed-off-by: Boris Brezillon > Tested-by: Kyle Roeschley > --- > v7: Move all code cleanup into first patch > Correct documentation of mark_bbt_block_bad > Make pr_warn messages consistent > Add Tested-bys > > v6: Split functionality of write_bbt out into new functions > > v5: De-duplicate bad block handling > > v4: Don't ignore write protection while marking bad BBT blocks > Correctly call block_markbad > Minor cleanups > > v3: Don't overload mtd->priv > Keep nand_erase_nand from erroring on protected BBT blocks > > v2: Mark OOB area in each block as well as BBT > Avoid marking read-only, bad address, or known bad blocks as bad > > drivers/mtd/nand/nand_bbt.c | 114 +++++++++++++++++++++++++++++--------------- > 1 file changed, 76 insertions(+), 38 deletions(-) > > diff --git a/drivers/mtd/nand/nand_bbt.c b/drivers/mtd/nand/nand_bbt.c > index 2fbb523..918db24 100644 > --- a/drivers/mtd/nand/nand_bbt.c > +++ b/drivers/mtd/nand/nand_bbt.c > @@ -605,6 +605,69 @@ static void search_read_bbts(struct mtd_info *mtd, uint8_t *buf, > } > > /** > + * get_bbt_block - Get the first valid eraseblock suitable to store a BBT > + * @this: the NAND device > + * @td: the BBT description > + * @md: the mirror BBT descriptor > + * @chip: the CHIP selector > + * > + * This functions returns a positive block number pointing a valid eraseblock > + * suitable to store a BBT (i.e. in the range reserved for BBT), or -ENOSPC if > + * all blocks are already used of marked bad. If td->pages[chip] was already > + * pointing to a valid block we re-use it, otherwise we search for the next > + * valid one. > + */ > +static int get_bbt_block(struct nand_chip *this, struct nand_bbt_descr *td, > + struct nand_bbt_descr *md, int chip) > +{ > + int startblock, dir, page, numblocks, i; > + > + /* > + * There was already a version of the table, reuse the page. This > + * applies for absolute placement too, as we have the page number in > + * td->pages. > + */ > + if (td->pages[chip] != -1) > + return td->pages[chip] >> > + (this->bbt_erase_shift - this->page_shift); > + > + numblocks = (int)(this->chipsize >> this->bbt_erase_shift); > + if (!(td->options & NAND_BBT_PERCHIP)) > + numblocks *= this->numchips; > + > + /* > + * Automatic placement of the bad block table. Search direction > + * top -> down? > + */ > + if (td->options & NAND_BBT_LASTBLOCK) { > + startblock = numblocks * (chip + 1) - 1; > + dir = -1; > + } else { > + startblock = chip * numblocks; > + dir = 1; > + } > + > + for (i = 0; i < td->maxblocks; i++) { > + int block = startblock + dir * i; > + > + /* Check, if the block is bad */ > + switch (bbt_get_entry(this, block)) { > + case BBT_BLOCK_WORN: > + case BBT_BLOCK_FACTORY_BAD: > + continue; > + } > + > + page = block << (this->bbt_erase_shift - this->page_shift); > + > + /* Check, if the block is used by the mirror table */ > + if (!md || md->pages[chip] != page) > + return block; > + } > + > + return -ENOSPC; > +} > + > +/** > * write_bbt - [GENERIC] (Re)write the bad block table > * @mtd: MTD device structure > * @buf: temporary buffer > @@ -621,7 +684,7 @@ static int write_bbt(struct mtd_info *mtd, uint8_t *buf, > struct nand_chip *this = mtd_to_nand(mtd); > struct erase_info einfo; > int i, res, chip = 0; > - int bits, startblock, dir, page, offs, numblocks, sft, sftmsk; > + int bits, page, offs, numblocks, sft, sftmsk; > int nrchips, pageoffs, ooboffs; > uint8_t msk[4]; > uint8_t rcode = td->reserved_block_code; > @@ -652,46 +715,21 @@ static int write_bbt(struct mtd_info *mtd, uint8_t *buf, > } > > /* Loop through the chips */ > - for (; chip < nrchips; chip++) { > - /* > - * There was already a version of the table, reuse the page > - * This applies for absolute placement too, as we have the > - * page nr. in td->pages. > - */ > - if (td->pages[chip] != -1) { > - page = td->pages[chip]; > - goto write; > + while (chip < nrchips) { I'm probably missing something, but why are you turning the for loop into a while loop in this patch? The commit message does not mention that, and I don't see why you need it before you actually start reworking the code to recover from BBT write failures (which is done in patch 2). > + int block; > + > + block = get_bbt_block(this, td, md, chip); > + if (block < 0) { > + pr_err("No space left to write bad block table\n"); > + res = block; > + goto outerr; > } > > /* > - * Automatic placement of the bad block table. Search direction > - * top -> down? > + * get_bbt_block() returns a block number, shift the value to > + * get a page number. > */ > - if (td->options & NAND_BBT_LASTBLOCK) { > - startblock = numblocks * (chip + 1) - 1; > - dir = -1; > - } else { > - startblock = chip * numblocks; > - dir = 1; > - } > - > - for (i = 0; i < td->maxblocks; i++) { > - int block = startblock + dir * i; > - /* Check, if the block is bad */ > - switch (bbt_get_entry(this, block)) { > - case BBT_BLOCK_WORN: > - case BBT_BLOCK_FACTORY_BAD: > - continue; > - } > - page = block << > - (this->bbt_erase_shift - this->page_shift); > - /* Check, if the block is used by the mirror table */ > - if (!md || md->pages[chip] != page) > - goto write; > - } > - pr_err("No space left to write bad block table\n"); > - return -ENOSPC; > - write: > + page = block << (this->bbt_erase_shift - this->page_shift); > > /* Set up shift count and masks for the flash table */ > bits = td->options & NAND_BBT_NRBITS_MSK; > @@ -800,7 +838,7 @@ static int write_bbt(struct mtd_info *mtd, uint8_t *buf, > (unsigned long long)to, td->version[chip]); > > /* Mark it as used */ > - td->pages[chip] = page; > + td->pages[chip++] = page; > } > return 0; >