Messages in this thread Patch in this message | | | Date | Fri, 10 Dec 2021 14:25:35 +0100 | From | Sean Nyekjaer <> | Subject | Re: [PATCH v5 3/4] mtd: core: protect access to MTD devices while in suspend |
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On Thu, Dec 09, 2021 at 03:28:11PM +0100, Miquel Raynal wrote: > Hi Sean, > > sean@geanix.com wrote on Thu, 9 Dec 2021 15:07:21 +0100: > > > On Fri, Dec 03, 2021 at 02:39:58PM +0100, Miquel Raynal wrote: > > > Hello, > > > > > > > > Fine by me, lets drop this series. > > > > > > FYI I've dropped the entire series from mtd/next. I'm waiting for the > > > fix discussed below (without abusing the chip mutex ;-) ). > > > > Cool, looking forward to test a patch series :) > > Test? You mean "write"? :) > > Cheers, > Miquèl
Hi Miquel,
Should we us a atomic for the suspended variable?
/Sean
diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c index b3a9bc08b4bb..eb4ec9a42d49 100644 --- a/drivers/mtd/nand/raw/nand_base.c +++ b/drivers/mtd/nand/raw/nand_base.c @@ -338,16 +338,19 @@ static int nand_isbad_bbm(struct nand_chip *chip, loff_t ofs) * * Return: -EBUSY if the chip has been suspended, 0 otherwise */ -static int nand_get_device(struct nand_chip *chip) +static void nand_get_device(struct nand_chip *chip) { - mutex_lock(&chip->lock); - if (chip->suspended) { + /* Wait until the device is resumed. */ + while (1) { + mutex_lock(&chip->lock); + if (!chip->suspended) { + mutex_lock(&chip->controller->lock); + return; + } mutex_unlock(&chip->lock); - return -EBUSY; - } - mutex_lock(&chip->controller->lock); - return 0; + wait_event(chip->resume_wq, !chip->suspended); + } } /** @@ -576,9 +579,7 @@ static int nand_block_markbad_lowlevel(struct nand_chip *chip, loff_t ofs) nand_erase_nand(chip, &einfo, 0); /* Write bad block marker to OOB */ - ret = nand_get_device(chip); - if (ret) - return ret; + nand_get_device(chip); ret = nand_markbad_bbm(chip, ofs); nand_release_device(chip); @@ -3759,9 +3760,7 @@ static int nand_read_oob(struct mtd_info *mtd, loff_t from, ops->mode != MTD_OPS_RAW) return -ENOTSUPP; - ret = nand_get_device(chip); - if (ret) - return ret; + nand_get_device(chip); if (!ops->datbuf) ret = nand_do_read_oob(chip, from, ops); @@ -4352,9 +4351,7 @@ static int nand_write_oob(struct mtd_info *mtd, loff_t to, ops->retlen = 0; - ret = nand_get_device(chip); - if (ret) - return ret; + nand_get_device(chip); switch (ops->mode) { case MTD_OPS_PLACE_OOB: @@ -4414,9 +4411,7 @@ int nand_erase_nand(struct nand_chip *chip, struct erase_info *instr, return -EIO; /* Grab the lock and see if the device is available */ - ret = nand_get_device(chip); - if (ret) - return ret; + nand_get_device(chip); /* Shift to get first page */ page = (int)(instr->addr >> chip->page_shift); @@ -4503,7 +4498,7 @@ static void nand_sync(struct mtd_info *mtd) pr_debug("%s: called\n", __func__); /* Grab the lock and see if the device is available */ - WARN_ON(nand_get_device(chip)); + nand_get_device(chip); /* Release it and go back */ nand_release_device(chip); } @@ -4520,9 +4515,7 @@ static int nand_block_isbad(struct mtd_info *mtd, loff_t offs) int ret; /* Select the NAND device */ - ret = nand_get_device(chip); - if (ret) - return ret; + nand_get_device(chip); nand_select_target(chip, chipnr); @@ -4593,6 +4586,8 @@ static void nand_resume(struct mtd_info *mtd) __func__); } mutex_unlock(&chip->lock); + + wake_up_all(&chip->resume_wq); } /** @@ -5370,6 +5365,7 @@ static int nand_scan_ident(struct nand_chip *chip, unsigned int maxchips, chip->cur_cs = -1; mutex_init(&chip->lock); + init_waitqueue_head(&chip->resume_wq); /* Enforce the right timings for reset/detection */ chip->current_interface_config = nand_get_reset_interface_config(); diff --git a/include/linux/mtd/rawnand.h b/include/linux/mtd/rawnand.h index b2f9dd3cbd69..248054560581 100644 --- a/include/linux/mtd/rawnand.h +++ b/include/linux/mtd/rawnand.h @@ -1294,6 +1294,7 @@ struct nand_chip { /* Internals */ struct mutex lock; unsigned int suspended : 1; + wait_queue_head_t resume_wq; int cur_cs; int read_retries; struct nand_secure_region *secure_regions;
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