Messages in this thread Patch in this message |  | | Date | Tue, 19 Oct 2021 20:08:00 +0200 | From | Sean Nyekjaer <> | Subject | Re: [PATCH 0/3] mtd: core: protect access to mtd devices while in suspend |
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On Fri, Oct 15, 2021 at 08:22:06AM +0200, Miquel Raynal wrote: > Hi Sean, > > boris.brezillon@collabora.com wrote on Mon, 11 Oct 2021 16:05:46 +0200: > > > On Mon, 11 Oct 2021 13:52:50 +0200
[ ... ]
> > > > One (small) issue still present. gpmi_nand.c uses the rwsem before it's > > > initialized. Seems cumbersome to have every mtd/nand driver to call > > > init_waitqueue_head() and init_rwsem(). Could we somehow move the call > > > to mtd_set_dev_defaults() before nand_create_bbt()? > > > > I have a nasty trick for that one, but I'm not sure Miquel will like it > > (actually, I don't like it either, but it's so simple compared to the > > other options we have that I'm tempted to go for this approach until > > someone has time to invest in a cleaner solution :-)): > > > > diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c > > index 3d6c6e880520..a9ac2d528a4d 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; > > @@ -6269,6 +6267,13 @@ static int nand_scan_tail(struct nand_chip *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; > > I'm fine with this as long as it is documented for now. >
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...
I have looked in the history and tried to blame gpmi-nand.c, but I can't see the reason to why NAND_SKIP_BBTSCAN is set.
I have tested Boris' hack with this diff (and it seems to work):
diff --git a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c index 4d08e4ab5c1b..ec7f44d630b6 100644 --- a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c +++ b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c @@ -2073,8 +2073,6 @@ static int gpmi_nand_attach_chip(struct nand_chip *chip) if (ret) return ret; - chip->options |= NAND_SKIP_BBTSCAN; - return 0; } @@ -2460,9 +2459,6 @@ static int gpmi_nand_init(struct gpmi_nand_data *this) goto err_out; ret = nand_boot_init(this); - if (ret) - goto err_nand_cleanup; - ret = nand_create_bbt(chip); if (ret) goto err_nand_cleanup; Do I miss something?
/Sean
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