Messages in this thread | | | Date | Wed, 20 Oct 2021 09:23:31 +0200 | From | Miquel Raynal <> | Subject | Re: [PATCH 0/3] mtd: core: protect access to mtd devices while in suspend |
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Hi Sean,
sean@geanix.com wrote on Wed, 20 Oct 2021 09:12:35 +0200:
> On Wed, Oct 20, 2021 at 09:00:58AM +0200, Boris Brezillon wrote: > > On Wed, 20 Oct 2021 08:52:50 +0200 > > Boris Brezillon <boris.brezillon@collabora.com> wrote: > > > > [ ... ] > > > > > > > > Hi Boris and Miquel, > > > > > > > > gpmi-nand.c sets NAND_SKIP_BBTSCAN so we won't get there and populate > > > > suspend resume hooks :( > > > > Guess there is other drivers that does the same thing... > > > > Actually, this version is even cleaner: > > > > diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c > > index 3d6c6e880520..98c39b7f6279 100644 > > --- a/drivers/mtd/nand/raw/nand_base.c > > +++ b/drivers/mtd/nand/raw/nand_base.c > > @@ -6222,8 +6222,6 @@ static int nand_scan_tail(struct nand_chip *chip) > > mtd->_sync = nand_sync; > > mtd->_lock = nand_lock; > > mtd->_unlock = nand_unlock; > > - mtd->_suspend = nand_suspend; > > - mtd->_resume = nand_resume; > > mtd->_reboot = nand_shutdown; > > mtd->_block_isreserved = nand_block_isreserved; > > mtd->_block_isbad = nand_block_isbad; > > @@ -6261,14 +6259,20 @@ static int nand_scan_tail(struct nand_chip *chip) > > goto err_free_interface_config; > > > > /* Check, if we should skip the bad block table scan */ > > - if (chip->options & NAND_SKIP_BBTSCAN) > > - return 0; > > - > > - /* Build bad block table */ > > - ret = nand_create_bbt(chip); > > - if (ret) > > - goto err_free_secure_regions; > > + if (chip->options & NAND_SKIP_BBTSCAN) { > > + /* Build bad block table */ > > + ret = nand_create_bbt(chip); > > + if (ret) > > + goto err_free_secure_regions; > > + } > > > > + /* > > + * Populate the suspend/resume hooks after the BBT has been scanned to > > + * avoid using the suspend lock and resume waitqueue which are only > > + * initialized when mtd_device_register() is called. > > + */ > > + mtd->_suspend = nand_suspend; > > + mtd->_resume = nand_resume; > > return 0; > > > > err_free_secure_regions: > > Why is the gpmi-nand.c and other drivers set NAND_SKIP_BBTSCAN and then > call nand_create_bbt() directly? > > To me it looks like legacy leftover...
It is...
885d71e5838f ("mtd: gpmi: fix the NULL pointer") added this flag to avoid a NULL pointer dereference on chip->buffer->databuf on mx23, which IIRC does not exist anymore.
I believe we could get rid of it. But anyway, I like the "cleanup" proposed by Boris so IMHO you can add these two patches to the series.
Thanks, Miquèl
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