Follow-up on discussion in:
https://lkml.org/lkml/2021/10/4/41
https://lkml.org/lkml/2021/10/11/435
Changes since v1:
- removed __mtd_suspend/__mtd_resume functions as they are not used by
mtdconcat anymore.
- only master mtd_info is used for mtd_{start,end}_access(). Warn if we
got mtd's.
- added Boris patch for using uninitialized _suspend/_resume hooks when
bbt scanning
- mtdconcat uses device _suspend/_resume hooks
- I don't really like the macro proposal from Boris
mtd_no_suspend_void_call()/mtd_no_suspend_ret_call() I think they
make the code complex to read and the macro's doesn't fit every
where anyway...
Changes since from rfc v1/v2:
- added access protection for all device access hooks in mtd_info.
- added Suggested-by to [1/3] patch.
- removed refereces to commit ef347c0cfd61 ("mtd: rawnand: gpmi: Implement exec_op")
from commit msg as commit 013e6292aaf5 ("mtd: rawnand: Simplify the locking") is
to be blamed.
- tested on a kernel with LOCKDEP enabled.
Sean Nyekjaer (4):
mtd: rawnand: nand_bbt: hide suspend/resume hooks while scanning bbt
mtd: core: protect access to MTD devices while in suspend
mtd: rawnand: remove suspended check
mtd: mtdconcat: add suspend lock handling
drivers/mtd/mtdconcat.c | 7 +-
drivers/mtd/mtdcore.c | 131 +++++++++++++++++++++++++++----
drivers/mtd/nand/raw/nand_base.c | 52 +++---------
drivers/mtd/nand/raw/nand_bbt.c | 28 ++++++-
include/linux/mtd/mtd.h | 81 +++++++++++++++----
include/linux/mtd/rawnand.h | 5 +-
6 files changed, 227 insertions(+), 77 deletions(-)
--
2.33.0
From: Boris Brezillon <[email protected]>
The BBT scan logic use the MTD helpers before the MTD layer had a
chance to initialize the device, and that leads to issues when
accessing the uninitialized suspend lock. Let's temporarily set the
suspend/resume hooks to NULL to skip the lock acquire/release step.
Fixes: 013e6292aaf5 ("mtd: rawnand: Simplify the locking")
Tested-by: Sean Nyekjaer <[email protected]>
---
drivers/mtd/nand/raw/nand_bbt.c | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)
diff --git a/drivers/mtd/nand/raw/nand_bbt.c b/drivers/mtd/nand/raw/nand_bbt.c
index b7ad030225f8..93d385703469 100644
--- a/drivers/mtd/nand/raw/nand_bbt.c
+++ b/drivers/mtd/nand/raw/nand_bbt.c
@@ -1397,8 +1397,28 @@ static int nand_create_badblock_pattern(struct nand_chip *this)
*/
int nand_create_bbt(struct nand_chip *this)
{
+ struct mtd_info *mtd = nand_to_mtd(this);
+ int (*suspend) (struct mtd_info *) = mtd->_suspend;
+ void (*resume) (struct mtd_info *) = mtd->_resume;
int ret;
+ /*
+ * The BBT scan logic use the MTD helpers before the MTD layer had a
+ * chance to initialize the device, and that leads to issues when
+ * accessing the uninitialized suspend lock. Let's temporarily set the
+ * suspend/resume hooks to NULL to skip the lock acquire/release step.
+ *
+ * FIXME: This is an ugly hack, so please don't copy this pattern to
+ * other MTD implementations. The proper fix would be to implement a
+ * generic BBT scan logic at the NAND level that's not using any of the
+ * MTD helpers to access pages. We also might consider doing a two
+ * step initialization at the MTD level (mtd_device_init() +
+ * mtd_device_register()) so some of the fields are initialized
+ * early.
+ */
+ mtd->_suspend = NULL;
+ mtd->_resume = NULL;
+
/* Is a flash based bad block table requested? */
if (this->bbt_options & NAND_BBT_USE_FLASH) {
/* Use the default pattern descriptors */
@@ -1422,7 +1442,13 @@ int nand_create_bbt(struct nand_chip *this)
return ret;
}
- return nand_scan_bbt(this, this->badblock_pattern);
+ ret = nand_scan_bbt(this, this->badblock_pattern);
+
+ /* Restore the suspend/resume hooks. */
+ mtd->_suspend = suspend;
+ mtd->_resume = resume;
+
+ return ret;
}
EXPORT_SYMBOL(nand_create_bbt);
--
2.33.0
Use MTD hooks to control suspend/resume of MTD devices.
Fixes: 013e6292aaf5 ("mtd: rawnand: Simplify the locking")
Suggested-by: Boris Brezillon <[email protected]>
Signed-off-by: Sean Nyekjaer <[email protected]>
---
drivers/mtd/mtdconcat.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/mtd/mtdconcat.c b/drivers/mtd/mtdconcat.c
index f685a581df48..1ec36890118f 100644
--- a/drivers/mtd/mtdconcat.c
+++ b/drivers/mtd/mtdconcat.c
@@ -566,9 +566,11 @@ static int concat_suspend(struct mtd_info *mtd)
for (i = 0; i < concat->num_subdev; i++) {
struct mtd_info *subdev = concat->subdev[i];
- if ((rc = mtd_suspend(subdev)) < 0)
+ rc = subdev->_suspend ? subdev->_suspend(subdev) : 0;
+ if (rc < 0)
return rc;
}
+
return rc;
}
@@ -579,7 +581,8 @@ static void concat_resume(struct mtd_info *mtd)
for (i = 0; i < concat->num_subdev; i++) {
struct mtd_info *subdev = concat->subdev[i];
- mtd_resume(subdev);
+ if (subdev->_resume)
+ subdev->_resume(subdev);
}
}
--
2.33.0
Access is protected in upper MTD layer when MTD devices are suspended.
Fixes: 013e6292aaf5 ("mtd: rawnand: Simplify the locking")
Reviewed-by: Miquel Raynal <[email protected]>
Signed-off-by: Sean Nyekjaer <[email protected]>
---
drivers/mtd/nand/raw/nand_base.c | 52 ++++++++------------------------
include/linux/mtd/rawnand.h | 5 +--
2 files changed, 14 insertions(+), 43 deletions(-)
diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
index 3d6c6e880520..aa2874ae3c4a 100644
--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c
@@ -332,19 +332,11 @@ static int nand_isbad_bbm(struct nand_chip *chip, loff_t ofs)
* @chip: NAND chip structure
*
* Lock the device and its controller for exclusive access
- *
- * 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) {
- mutex_unlock(&chip->lock);
- return -EBUSY;
- }
mutex_lock(&chip->controller->lock);
-
- return 0;
}
/**
@@ -573,10 +565,7 @@ 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);
}
@@ -3756,9 +3745,7 @@ 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);
@@ -4345,13 +4332,11 @@ static int nand_write_oob(struct mtd_info *mtd, loff_t to,
struct mtd_oob_ops *ops)
{
struct nand_chip *chip = mtd_to_nand(mtd);
- int ret;
+ int ret = 0;
ops->retlen = 0;
- ret = nand_get_device(chip);
- if (ret)
- return ret;
+ nand_get_device(chip);
switch (ops->mode) {
case MTD_OPS_PLACE_OOB:
@@ -4410,10 +4395,8 @@ int nand_erase_nand(struct nand_chip *chip, struct erase_info *instr,
if (nand_region_is_secured(chip, instr->addr, instr->len))
return -EIO;
- /* Grab the lock and see if the device is available */
- ret = nand_get_device(chip);
- if (ret)
- return ret;
+ /* Grab the lock */
+ nand_get_device(chip);
/* Shift to get first page */
page = (int)(instr->addr >> chip->page_shift);
@@ -4499,8 +4482,8 @@ 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));
+ /* Grab the lock */
+ nand_get_device(chip);
/* Release it and go back */
nand_release_device(chip);
}
@@ -4517,9 +4500,7 @@ 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);
@@ -4565,8 +4546,6 @@ static int nand_suspend(struct mtd_info *mtd)
mutex_lock(&chip->lock);
if (chip->ops.suspend)
ret = chip->ops.suspend(chip);
- if (!ret)
- chip->suspended = 1;
mutex_unlock(&chip->lock);
return ret;
@@ -4580,15 +4559,10 @@ static void nand_resume(struct mtd_info *mtd)
{
struct nand_chip *chip = mtd_to_nand(mtd);
+
mutex_lock(&chip->lock);
- if (chip->suspended) {
- if (chip->ops.resume)
- chip->ops.resume(chip);
- chip->suspended = 0;
- } else {
- pr_err("%s called for a chip which is not in suspended state\n",
- __func__);
- }
+ if (chip->ops.resume)
+ chip->ops.resume(chip);
mutex_unlock(&chip->lock);
}
diff --git a/include/linux/mtd/rawnand.h b/include/linux/mtd/rawnand.h
index b2f9dd3cbd69..1198a6548912 100644
--- a/include/linux/mtd/rawnand.h
+++ b/include/linux/mtd/rawnand.h
@@ -1237,9 +1237,7 @@ struct nand_secure_region {
* @pagecache.page: Page number currently in the cache. -1 means no page is
* currently cached
* @buf_align: Minimum buffer alignment required by a platform
- * @lock: Lock protecting the suspended field. Also used to serialize accesses
- * to the NAND device
- * @suspended: Set to 1 when the device is suspended, 0 when it's not
+ * @lock: Lock to serialize accesses to the NAND device
* @cur_cs: Currently selected target. -1 means no target selected, otherwise we
* should always have cur_cs >= 0 && cur_cs < nanddev_ntargets().
* NAND Controller drivers should not modify this value, but they're
@@ -1293,7 +1291,6 @@ struct nand_chip {
/* Internals */
struct mutex lock;
- unsigned int suspended : 1;
int cur_cs;
int read_retries;
struct nand_secure_region *secure_regions;
--
2.33.0
Prevent accessing the devices while in a suspended state. Also
prevent suspending a device which is still currently in use.
Commit 013e6292aaf5 ("mtd: rawnand: Simplify the locking") allows the
rawnand layer to return errors rather than waiting in a blocking wait.
Tested on a iMX6ULL.
Fixes: 013e6292aaf5 ("mtd: rawnand: Simplify the locking")
Suggested-by: Boris Brezillon <[email protected]>
Signed-off-by: Sean Nyekjaer <[email protected]>
---
drivers/mtd/mtdcore.c | 131 ++++++++++++++++++++++++++++++++++------
include/linux/mtd/mtd.h | 81 ++++++++++++++++++++-----
2 files changed, 181 insertions(+), 31 deletions(-)
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 153229198947..310d1f86a77b 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -777,6 +777,8 @@ static void mtd_set_dev_defaults(struct mtd_info *mtd)
INIT_LIST_HEAD(&mtd->partitions);
mutex_init(&mtd->master.partitions_lock);
mutex_init(&mtd->master.chrdev_lock);
+ init_waitqueue_head(&mtd->master.resume_wq);
+ init_rwsem(&mtd->master.suspend_lock);
}
static ssize_t mtd_otp_size(struct mtd_info *mtd, bool is_user)
@@ -1257,6 +1259,8 @@ int mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
ledtrig_mtd_activity();
+ mtd_start_access(master);
+
if (mtd->flags & MTD_SLC_ON_MLC_EMULATION) {
adjinstr.addr = (loff_t)mtd_div_by_eb(instr->addr, mtd) *
master->erasesize;
@@ -1278,6 +1282,8 @@ int mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
}
}
+ mtd_end_access(master);
+
return ret;
}
EXPORT_SYMBOL_GPL(mtd_erase);
@@ -1289,6 +1295,7 @@ int mtd_point(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
void **virt, resource_size_t *phys)
{
struct mtd_info *master = mtd_get_master(mtd);
+ int ret;
*retlen = 0;
*virt = NULL;
@@ -1301,8 +1308,12 @@ int mtd_point(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
if (!len)
return 0;
+ mtd_start_access(master);
from = mtd_get_master_ofs(mtd, from);
- return master->_point(master, from, len, retlen, virt, phys);
+ ret = master->_point(master, from, len, retlen, virt, phys);
+ mtd_end_access(master);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(mtd_point);
@@ -1310,6 +1321,7 @@ EXPORT_SYMBOL_GPL(mtd_point);
int mtd_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
{
struct mtd_info *master = mtd_get_master(mtd);
+ int ret;
if (!master->_unpoint)
return -EOPNOTSUPP;
@@ -1317,7 +1329,12 @@ int mtd_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
return -EINVAL;
if (!len)
return 0;
- return master->_unpoint(master, mtd_get_master_ofs(mtd, from), len);
+
+ mtd_start_access(master);
+ ret = master->_unpoint(master, mtd_get_master_ofs(mtd, from), len);
+ mtd_end_access(master);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(mtd_unpoint);
@@ -1372,6 +1389,7 @@ int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
};
int ret;
+ /* mtd_read_oob_std handles mtd access protection */
ret = mtd_read_oob(mtd, from, &ops);
*retlen = ops.retlen;
@@ -1388,6 +1406,7 @@ int mtd_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
};
int ret;
+ /* mtd_write_oob_std handles mtd access protection */
ret = mtd_write_oob(mtd, to, &ops);
*retlen = ops.retlen;
@@ -1406,6 +1425,7 @@ int mtd_panic_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
const u_char *buf)
{
struct mtd_info *master = mtd_get_master(mtd);
+ int ret;
*retlen = 0;
if (!master->_panic_write)
@@ -1419,8 +1439,12 @@ int mtd_panic_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
if (!master->oops_panic_write)
master->oops_panic_write = true;
- return master->_panic_write(master, mtd_get_master_ofs(mtd, to), len,
- retlen, buf);
+ mtd_start_access(master);
+ ret = master->_panic_write(master, mtd_get_master_ofs(mtd, to), len,
+ retlen, buf);
+ mtd_end_access(master);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(mtd_panic_write);
@@ -1464,11 +1488,13 @@ static int mtd_read_oob_std(struct mtd_info *mtd, loff_t from,
int ret;
from = mtd_get_master_ofs(mtd, from);
+ mtd_start_access(master);
if (master->_read_oob)
ret = master->_read_oob(master, from, ops);
else
ret = master->_read(master, from, ops->len, &ops->retlen,
ops->datbuf);
+ mtd_end_access(master);
return ret;
}
@@ -1480,11 +1506,13 @@ static int mtd_write_oob_std(struct mtd_info *mtd, loff_t to,
int ret;
to = mtd_get_master_ofs(mtd, to);
+ mtd_start_access(master);
if (master->_write_oob)
ret = master->_write_oob(master, to, ops);
else
ret = master->_write(master, to, ops->len, &ops->retlen,
ops->datbuf);
+ mtd_end_access(master);
return ret;
}
@@ -1576,7 +1604,6 @@ int mtd_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
ret_code = mtd_read_oob_std(mtd, from, ops);
mtd_update_ecc_stats(mtd, master, &old_stats);
-
/*
* In cases where ops->datbuf != NULL, mtd->_read_oob() has semantics
* similar to mtd->_read(), returning a non-negative integer
@@ -1615,7 +1642,9 @@ int mtd_write_oob(struct mtd_info *mtd, loff_t to,
if (mtd->flags & MTD_SLC_ON_MLC_EMULATION)
return mtd_io_emulated_slc(mtd, to, false, ops);
- return mtd_write_oob_std(mtd, to, ops);
+ ret = mtd_write_oob_std(mtd, to, ops);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(mtd_write_oob);
@@ -1992,12 +2021,18 @@ int mtd_get_fact_prot_info(struct mtd_info *mtd, size_t len, size_t *retlen,
struct otp_info *buf)
{
struct mtd_info *master = mtd_get_master(mtd);
+ int ret;
if (!master->_get_fact_prot_info)
return -EOPNOTSUPP;
if (!len)
return 0;
- return master->_get_fact_prot_info(master, len, retlen, buf);
+
+ mtd_start_access(master);
+ ret = master->_get_fact_prot_info(master, len, retlen, buf);
+ mtd_end_access(master);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(mtd_get_fact_prot_info);
@@ -2005,13 +2040,19 @@ int mtd_read_fact_prot_reg(struct mtd_info *mtd, loff_t from, size_t len,
size_t *retlen, u_char *buf)
{
struct mtd_info *master = mtd_get_master(mtd);
+ int ret;
*retlen = 0;
if (!master->_read_fact_prot_reg)
return -EOPNOTSUPP;
if (!len)
return 0;
- return master->_read_fact_prot_reg(master, from, len, retlen, buf);
+
+ mtd_start_access(master);
+ ret = master->_read_fact_prot_reg(master, from, len, retlen, buf);
+ mtd_end_access(master);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(mtd_read_fact_prot_reg);
@@ -2019,12 +2060,18 @@ int mtd_get_user_prot_info(struct mtd_info *mtd, size_t len, size_t *retlen,
struct otp_info *buf)
{
struct mtd_info *master = mtd_get_master(mtd);
+ int ret;
if (!master->_get_user_prot_info)
return -EOPNOTSUPP;
if (!len)
return 0;
- return master->_get_user_prot_info(master, len, retlen, buf);
+
+ mtd_start_access(master);
+ ret = master->_get_user_prot_info(master, len, retlen, buf);
+ mtd_end_access(master);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(mtd_get_user_prot_info);
@@ -2032,13 +2079,19 @@ int mtd_read_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len,
size_t *retlen, u_char *buf)
{
struct mtd_info *master = mtd_get_master(mtd);
+ int ret;
*retlen = 0;
if (!master->_read_user_prot_reg)
return -EOPNOTSUPP;
if (!len)
return 0;
- return master->_read_user_prot_reg(master, from, len, retlen, buf);
+
+ mtd_start_access(master);
+ ret = master->_read_user_prot_reg(master, from, len, retlen, buf);
+ mtd_end_access(master);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(mtd_read_user_prot_reg);
@@ -2053,7 +2106,11 @@ int mtd_write_user_prot_reg(struct mtd_info *mtd, loff_t to, size_t len,
return -EOPNOTSUPP;
if (!len)
return 0;
+
+ mtd_start_access(master);
ret = master->_write_user_prot_reg(master, to, len, retlen, buf);
+ mtd_end_access(master);
+
if (ret)
return ret;
@@ -2068,24 +2125,36 @@ EXPORT_SYMBOL_GPL(mtd_write_user_prot_reg);
int mtd_lock_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len)
{
struct mtd_info *master = mtd_get_master(mtd);
+ int ret;
if (!master->_lock_user_prot_reg)
return -EOPNOTSUPP;
if (!len)
return 0;
- return master->_lock_user_prot_reg(master, from, len);
+
+ mtd_start_access(master);
+ ret = master->_lock_user_prot_reg(master, from, len);
+ mtd_end_access(master);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(mtd_lock_user_prot_reg);
int mtd_erase_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len)
{
struct mtd_info *master = mtd_get_master(mtd);
+ int ret;
if (!master->_erase_user_prot_reg)
return -EOPNOTSUPP;
if (!len)
return 0;
- return master->_erase_user_prot_reg(master, from, len);
+
+ mtd_start_access(master);
+ ret = master->_erase_user_prot_reg(master, from, len);
+ mtd_end_access(master);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(mtd_erase_user_prot_reg);
@@ -2093,6 +2162,7 @@ EXPORT_SYMBOL_GPL(mtd_erase_user_prot_reg);
int mtd_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
struct mtd_info *master = mtd_get_master(mtd);
+ int ret;
if (!master->_lock)
return -EOPNOTSUPP;
@@ -2106,13 +2176,18 @@ int mtd_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
len = (u64)mtd_div_by_eb(len, mtd) * master->erasesize;
}
- return master->_lock(master, mtd_get_master_ofs(mtd, ofs), len);
+ mtd_start_access(master);
+ ret = master->_lock(master, mtd_get_master_ofs(mtd, ofs), len);
+ mtd_end_access(master);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(mtd_lock);
int mtd_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
struct mtd_info *master = mtd_get_master(mtd);
+ int ret;
if (!master->_unlock)
return -EOPNOTSUPP;
@@ -2126,13 +2201,18 @@ int mtd_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
len = (u64)mtd_div_by_eb(len, mtd) * master->erasesize;
}
- return master->_unlock(master, mtd_get_master_ofs(mtd, ofs), len);
+ mtd_start_access(master);
+ ret = master->_unlock(master, mtd_get_master_ofs(mtd, ofs), len);
+ mtd_end_access(master);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(mtd_unlock);
int mtd_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
struct mtd_info *master = mtd_get_master(mtd);
+ int ret;
if (!master->_is_locked)
return -EOPNOTSUPP;
@@ -2146,13 +2226,18 @@ int mtd_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
len = (u64)mtd_div_by_eb(len, mtd) * master->erasesize;
}
- return master->_is_locked(master, mtd_get_master_ofs(mtd, ofs), len);
+ mtd_start_access(master);
+ ret = master->_is_locked(master, mtd_get_master_ofs(mtd, ofs), len);
+ mtd_end_access(master);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(mtd_is_locked);
int mtd_block_isreserved(struct mtd_info *mtd, loff_t ofs)
{
struct mtd_info *master = mtd_get_master(mtd);
+ int ret;
if (ofs < 0 || ofs >= mtd->size)
return -EINVAL;
@@ -2162,13 +2247,18 @@ int mtd_block_isreserved(struct mtd_info *mtd, loff_t ofs)
if (mtd->flags & MTD_SLC_ON_MLC_EMULATION)
ofs = (loff_t)mtd_div_by_eb(ofs, mtd) * master->erasesize;
- return master->_block_isreserved(master, mtd_get_master_ofs(mtd, ofs));
+ mtd_start_access(master);
+ ret = master->_block_isreserved(master, mtd_get_master_ofs(mtd, ofs));
+ mtd_end_access(master);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(mtd_block_isreserved);
int mtd_block_isbad(struct mtd_info *mtd, loff_t ofs)
{
struct mtd_info *master = mtd_get_master(mtd);
+ int ret;
if (ofs < 0 || ofs >= mtd->size)
return -EINVAL;
@@ -2178,7 +2268,11 @@ int mtd_block_isbad(struct mtd_info *mtd, loff_t ofs)
if (mtd->flags & MTD_SLC_ON_MLC_EMULATION)
ofs = (loff_t)mtd_div_by_eb(ofs, mtd) * master->erasesize;
- return master->_block_isbad(master, mtd_get_master_ofs(mtd, ofs));
+ mtd_start_access(master);
+ ret = master->_block_isbad(master, mtd_get_master_ofs(mtd, ofs));
+ mtd_end_access(master);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(mtd_block_isbad);
@@ -2197,7 +2291,10 @@ int mtd_block_markbad(struct mtd_info *mtd, loff_t ofs)
if (mtd->flags & MTD_SLC_ON_MLC_EMULATION)
ofs = (loff_t)mtd_div_by_eb(ofs, mtd) * master->erasesize;
+ mtd_start_access(master);
ret = master->_block_markbad(master, mtd_get_master_ofs(mtd, ofs));
+ mtd_end_access(master);
+
if (ret)
return ret;
diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index 88227044fc86..5c7d8de2d900 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -231,6 +231,8 @@ struct mtd_master {
struct mutex partitions_lock;
struct mutex chrdev_lock;
unsigned int suspended : 1;
+ wait_queue_head_t resume_wq;
+ struct rw_semaphore suspend_lock;
};
struct mtd_info {
@@ -476,10 +478,47 @@ static inline u32 mtd_oobavail(struct mtd_info *mtd, struct mtd_oob_ops *ops)
return ops->mode == MTD_OPS_AUTO_OOB ? mtd->oobavail : mtd->oobsize;
}
+static inline void mtd_start_access(struct mtd_info *master)
+{
+ WARN_ON_ONCE(master != mtd_get_master(master));
+
+ /*
+ * Don't take the suspend_lock on devices that don't
+ * implement the suspend hook. Otherwise, lockdep will
+ * complain about nested locks when trying to suspend MTD
+ * partitions or MTD devices created by gluebi which are
+ * backed by real devices.
+ */
+ if (!master->_suspend)
+ return;
+
+ /*
+ * Wait until the device is resumed. Should we have a
+ * non-blocking mode here?
+ */
+ while (1) {
+ down_read(&master->master.suspend_lock);
+ if (!master->master.suspended)
+ return;
+
+ up_read(&master->master.suspend_lock);
+ wait_event(master->master.resume_wq, master->master.suspended == 0);
+ }
+}
+
+static inline void mtd_end_access(struct mtd_info *master)
+{
+ if (!master->_suspend)
+ return;
+
+ up_read(&master->master.suspend_lock);
+}
+
static inline int mtd_max_bad_blocks(struct mtd_info *mtd,
loff_t ofs, size_t len)
{
struct mtd_info *master = mtd_get_master(mtd);
+ int ret;
if (!master->_max_bad_blocks)
return -ENOTSUPP;
@@ -487,8 +526,12 @@ static inline int mtd_max_bad_blocks(struct mtd_info *mtd,
if (mtd->size < (len + ofs) || ofs < 0)
return -EINVAL;
- return master->_max_bad_blocks(master, mtd_get_master_ofs(mtd, ofs),
- len);
+ mtd_start_access(master);
+ ret = master->_max_bad_blocks(master, mtd_get_master_ofs(mtd, ofs),
+ len);
+ mtd_end_access(master);
+
+ return ret;
}
int mtd_wunit_to_pairing_info(struct mtd_info *mtd, int wunit,
@@ -546,30 +589,40 @@ int mtd_block_markbad(struct mtd_info *mtd, loff_t ofs);
static inline int mtd_suspend(struct mtd_info *mtd)
{
struct mtd_info *master = mtd_get_master(mtd);
- int ret;
-
- if (master->master.suspended)
- return 0;
+ int ret = 0;
- ret = master->_suspend ? master->_suspend(master) : 0;
- if (ret)
+ if (!master->_suspend)
return ret;
- master->master.suspended = 1;
- return 0;
+ down_write(&master->master.suspend_lock);
+ if (!master->master.suspended) {
+ ret = master->_suspend(master);
+ if (!ret)
+ master->master.suspended = 1;
+ }
+ up_write(&master->master.suspend_lock);
+
+ return ret;
}
static inline void mtd_resume(struct mtd_info *mtd)
{
struct mtd_info *master = mtd_get_master(mtd);
- if (!master->master.suspended)
+ if (!master->_suspend)
return;
- if (master->_resume)
- master->_resume(master);
+ down_write(&master->master.suspend_lock);
+ if (master->master.suspended) {
+ if (master->_resume)
+ master->_resume(master);
+
+ master->master.suspended = 0;
- master->master.suspended = 0;
+ /* The MTD dev has been resumed, wake up all waiters. */
+ wake_up_all(&master->master.resume_wq);
+ }
+ up_write(&master->master.suspend_lock);
}
static inline uint32_t mtd_div_by_eb(uint64_t sz, struct mtd_info *mtd)
--
2.33.0
On Wed, 20 Oct 2021 10:45:31 +0200
Sean Nyekjaer <[email protected]> wrote:
> From: Boris Brezillon <[email protected]>
>
> The BBT scan logic use the MTD helpers before the MTD layer had a
> chance to initialize the device, and that leads to issues when
> accessing the uninitialized suspend lock. Let's temporarily set the
> suspend/resume hooks to NULL to skip the lock acquire/release step.
>
> Fixes: 013e6292aaf5 ("mtd: rawnand: Simplify the locking")
> Tested-by: Sean Nyekjaer <[email protected]>
It's missing our Signed-off-by tags.
> ---
> drivers/mtd/nand/raw/nand_bbt.c | 28 +++++++++++++++++++++++++++-
> 1 file changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/nand/raw/nand_bbt.c b/drivers/mtd/nand/raw/nand_bbt.c
> index b7ad030225f8..93d385703469 100644
> --- a/drivers/mtd/nand/raw/nand_bbt.c
> +++ b/drivers/mtd/nand/raw/nand_bbt.c
> @@ -1397,8 +1397,28 @@ static int nand_create_badblock_pattern(struct nand_chip *this)
> */
> int nand_create_bbt(struct nand_chip *this)
> {
> + struct mtd_info *mtd = nand_to_mtd(this);
> + int (*suspend) (struct mtd_info *) = mtd->_suspend;
> + void (*resume) (struct mtd_info *) = mtd->_resume;
> int ret;
>
> + /*
> + * The BBT scan logic use the MTD helpers before the MTD layer had a
> + * chance to initialize the device, and that leads to issues when
> + * accessing the uninitialized suspend lock. Let's temporarily set the
> + * suspend/resume hooks to NULL to skip the lock acquire/release step.
> + *
> + * FIXME: This is an ugly hack, so please don't copy this pattern to
> + * other MTD implementations. The proper fix would be to implement a
> + * generic BBT scan logic at the NAND level that's not using any of the
> + * MTD helpers to access pages. We also might consider doing a two
> + * step initialization at the MTD level (mtd_device_init() +
> + * mtd_device_register()) so some of the fields are initialized
> + * early.
> + */
> + mtd->_suspend = NULL;
> + mtd->_resume = NULL;
> +
> /* Is a flash based bad block table requested? */
> if (this->bbt_options & NAND_BBT_USE_FLASH) {
> /* Use the default pattern descriptors */
> @@ -1422,7 +1442,13 @@ int nand_create_bbt(struct nand_chip *this)
> return ret;
> }
>
> - return nand_scan_bbt(this, this->badblock_pattern);
> + ret = nand_scan_bbt(this, this->badblock_pattern);
> +
> + /* Restore the suspend/resume hooks. */
> + mtd->_suspend = suspend;
> + mtd->_resume = resume;
> +
> + return ret;
> }
> EXPORT_SYMBOL(nand_create_bbt);
>
On Wed, 20 Oct 2021 10:45:34 +0200
Sean Nyekjaer <[email protected]> wrote:
> Use MTD hooks to control suspend/resume of MTD devices.
Please explain in great details why this is needed.
>
> Fixes: 013e6292aaf5 ("mtd: rawnand: Simplify the locking")
> Suggested-by: Boris Brezillon <[email protected]>
> Signed-off-by: Sean Nyekjaer <[email protected]>
This patch should be moved earlier (before 'mtd: core: protect access to
MTD devices while in suspend') in the series.
> ---
> drivers/mtd/mtdconcat.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mtd/mtdconcat.c b/drivers/mtd/mtdconcat.c
> index f685a581df48..1ec36890118f 100644
> --- a/drivers/mtd/mtdconcat.c
> +++ b/drivers/mtd/mtdconcat.c
> @@ -566,9 +566,11 @@ static int concat_suspend(struct mtd_info *mtd)
>
> for (i = 0; i < concat->num_subdev; i++) {
> struct mtd_info *subdev = concat->subdev[i];
> - if ((rc = mtd_suspend(subdev)) < 0)
> + rc = subdev->_suspend ? subdev->_suspend(subdev) : 0;
> + if (rc < 0)
> return rc;
Same here, you need a fat comment explaining why mtd_suspend() is not
used.
> }
> +
> return rc;
> }
>
> @@ -579,7 +581,8 @@ static void concat_resume(struct mtd_info *mtd)
>
> for (i = 0; i < concat->num_subdev; i++) {
> struct mtd_info *subdev = concat->subdev[i];
> - mtd_resume(subdev);
> + if (subdev->_resume)
> + subdev->_resume(subdev);
Ditto.
> }
> }
>
On Wed, 20 Oct 2021 10:45:33 +0200
Sean Nyekjaer <[email protected]> wrote:
> Access is protected in upper MTD layer when MTD devices are suspended.
I think it deserves more explanation.
>
> Fixes: 013e6292aaf5 ("mtd: rawnand: Simplify the locking")
This patch doesn't fix anything, things have been fixed in 'mtd: core:
protect access to MTD devices while in suspend'. It's just a cleanup on
top of it.
> Reviewed-by: Miquel Raynal <[email protected]>
> Signed-off-by: Sean Nyekjaer <[email protected]>
> ---
> drivers/mtd/nand/raw/nand_base.c | 52 ++++++++------------------------
> include/linux/mtd/rawnand.h | 5 +--
> 2 files changed, 14 insertions(+), 43 deletions(-)
>
> diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
> index 3d6c6e880520..aa2874ae3c4a 100644
> --- a/drivers/mtd/nand/raw/nand_base.c
> +++ b/drivers/mtd/nand/raw/nand_base.c
> @@ -332,19 +332,11 @@ static int nand_isbad_bbm(struct nand_chip *chip, loff_t ofs)
> * @chip: NAND chip structure
> *
> * Lock the device and its controller for exclusive access
> - *
> - * 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) {
> - mutex_unlock(&chip->lock);
> - return -EBUSY;
> - }
> mutex_lock(&chip->controller->lock);
> -
> - return 0;
> }
>
> /**
> @@ -573,10 +565,7 @@ 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);
> }
> @@ -3756,9 +3745,7 @@ 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);
> @@ -4345,13 +4332,11 @@ static int nand_write_oob(struct mtd_info *mtd, loff_t to,
> struct mtd_oob_ops *ops)
> {
> struct nand_chip *chip = mtd_to_nand(mtd);
> - int ret;
> + int ret = 0;
>
> ops->retlen = 0;
>
> - ret = nand_get_device(chip);
> - if (ret)
> - return ret;
> + nand_get_device(chip);
>
> switch (ops->mode) {
> case MTD_OPS_PLACE_OOB:
> @@ -4410,10 +4395,8 @@ int nand_erase_nand(struct nand_chip *chip, struct erase_info *instr,
> if (nand_region_is_secured(chip, instr->addr, instr->len))
> return -EIO;
>
> - /* Grab the lock and see if the device is available */
> - ret = nand_get_device(chip);
> - if (ret)
> - return ret;
> + /* Grab the lock */
> + nand_get_device(chip);
>
> /* Shift to get first page */
> page = (int)(instr->addr >> chip->page_shift);
> @@ -4499,8 +4482,8 @@ 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));
> + /* Grab the lock */
> + nand_get_device(chip);
> /* Release it and go back */
> nand_release_device(chip);
> }
> @@ -4517,9 +4500,7 @@ 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);
>
> @@ -4565,8 +4546,6 @@ static int nand_suspend(struct mtd_info *mtd)
> mutex_lock(&chip->lock);
> if (chip->ops.suspend)
> ret = chip->ops.suspend(chip);
> - if (!ret)
> - chip->suspended = 1;
> mutex_unlock(&chip->lock);
>
> return ret;
> @@ -4580,15 +4559,10 @@ static void nand_resume(struct mtd_info *mtd)
> {
> struct nand_chip *chip = mtd_to_nand(mtd);
>
> +
> mutex_lock(&chip->lock);
> - if (chip->suspended) {
> - if (chip->ops.resume)
> - chip->ops.resume(chip);
> - chip->suspended = 0;
> - } else {
> - pr_err("%s called for a chip which is not in suspended state\n",
> - __func__);
> - }
> + if (chip->ops.resume)
> + chip->ops.resume(chip);
> mutex_unlock(&chip->lock);
> }
>
> diff --git a/include/linux/mtd/rawnand.h b/include/linux/mtd/rawnand.h
> index b2f9dd3cbd69..1198a6548912 100644
> --- a/include/linux/mtd/rawnand.h
> +++ b/include/linux/mtd/rawnand.h
> @@ -1237,9 +1237,7 @@ struct nand_secure_region {
> * @pagecache.page: Page number currently in the cache. -1 means no page is
> * currently cached
> * @buf_align: Minimum buffer alignment required by a platform
> - * @lock: Lock protecting the suspended field. Also used to serialize accesses
> - * to the NAND device
> - * @suspended: Set to 1 when the device is suspended, 0 when it's not
> + * @lock: Lock to serialize accesses to the NAND device
> * @cur_cs: Currently selected target. -1 means no target selected, otherwise we
> * should always have cur_cs >= 0 && cur_cs < nanddev_ntargets().
> * NAND Controller drivers should not modify this value, but they're
> @@ -1293,7 +1291,6 @@ struct nand_chip {
>
> /* Internals */
> struct mutex lock;
> - unsigned int suspended : 1;
> int cur_cs;
> int read_retries;
> struct nand_secure_region *secure_regions;
On Wed, 20 Oct 2021 11:01:32 +0200
Sean Nyekjaer <[email protected]> wrote:
> On Wed, Oct 20, 2021 at 10:53:26AM +0200, Boris Brezillon wrote:
> > On Wed, 20 Oct 2021 10:45:31 +0200
> > Sean Nyekjaer <[email protected]> wrote:
> >
> > > From: Boris Brezillon <[email protected]>
> > >
> > > The BBT scan logic use the MTD helpers before the MTD layer had a
> > > chance to initialize the device, and that leads to issues when
> > > accessing the uninitialized suspend lock. Let's temporarily set the
> > > suspend/resume hooks to NULL to skip the lock acquire/release step.
> > >
> > > Fixes: 013e6292aaf5 ("mtd: rawnand: Simplify the locking")
> > > Tested-by: Sean Nyekjaer <[email protected]>
> >
> > It's missing our Signed-off-by tags.
> >
>
> Patch is from you ;)
> If you are okay with it, I will add your Signed-off-by tag.
You should add both (mine and yours).
On Wed, Oct 20, 2021 at 10:53:26AM +0200, Boris Brezillon wrote:
> On Wed, 20 Oct 2021 10:45:31 +0200
> Sean Nyekjaer <[email protected]> wrote:
>
> > From: Boris Brezillon <[email protected]>
> >
> > The BBT scan logic use the MTD helpers before the MTD layer had a
> > chance to initialize the device, and that leads to issues when
> > accessing the uninitialized suspend lock. Let's temporarily set the
> > suspend/resume hooks to NULL to skip the lock acquire/release step.
> >
> > Fixes: 013e6292aaf5 ("mtd: rawnand: Simplify the locking")
> > Tested-by: Sean Nyekjaer <[email protected]>
>
> It's missing our Signed-off-by tags.
>
Patch is from you ;)
If you are okay with it, I will add your Signed-off-by tag.
/Sean
Hi Boris,
[email protected] wrote on Wed, 20 Oct 2021 11:03:03 +0200:
> On Wed, 20 Oct 2021 11:01:32 +0200
> Sean Nyekjaer <[email protected]> wrote:
>
> > On Wed, Oct 20, 2021 at 10:53:26AM +0200, Boris Brezillon wrote:
> > > On Wed, 20 Oct 2021 10:45:31 +0200
> > > Sean Nyekjaer <[email protected]> wrote:
> > >
> > > > From: Boris Brezillon <[email protected]>
> > > >
> > > > The BBT scan logic use the MTD helpers before the MTD layer had a
> > > > chance to initialize the device, and that leads to issues when
> > > > accessing the uninitialized suspend lock. Let's temporarily set the
> > > > suspend/resume hooks to NULL to skip the lock acquire/release step.
> > > >
> > > > Fixes: 013e6292aaf5 ("mtd: rawnand: Simplify the locking")
> > > > Tested-by: Sean Nyekjaer <[email protected]>
> > >
> > > It's missing our Signed-off-by tags.
> > >
> >
> > Patch is from you ;)
> > If you are okay with it, I will add your Signed-off-by tag.
>
> You should add both (mine and yours).
And put the one matching the author (Boris') before the other (yours).
On Wed, 20 Oct 2021 10:45:32 +0200
Sean Nyekjaer <[email protected]> wrote:
> static ssize_t mtd_otp_size(struct mtd_info *mtd, bool is_user)
> @@ -1257,6 +1259,8 @@ int mtd_erase(struct mtd_info *mtd, sruct erase_info *instr)
>
> ledtrig_mtd_activity();
>
> + mtd_start_access(master);
> +
> if (mtd->flags & MTD_SLC_ON_MLC_EMULATION) {
> adjinstr.addr = (loff_t)mtd_div_by_eb(instr->addr, mtd) *
> master->erasesize;
> @@ -1278,6 +1282,8 @@ int mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
> }
> }
>
> + mtd_end_access(master);
> +
The section covered in mtd_erase() is too broad. Put the start/end
calls around the ->_erase() call.
> return ret;
> }
> @@ -1576,7 +1604,6 @@ int mtd_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
> ret_code = mtd_read_oob_std(mtd, from, ops);
>
> mtd_update_ecc_stats(mtd, master, &old_stats);
> -
Unrelated line removal. Please drop this change.
> /*
> * In cases where ops->datbuf != NULL, mtd->_read_oob() has semantics
> * similar to mtd->_read(), returning a non-negative integer
> @@ -1615,7 +1642,9 @@ int mtd_write_oob(struct mtd_info *mtd, loff_t to,
> if (mtd->flags & MTD_SLC_ON_MLC_EMULATION)
> return mtd_io_emulated_slc(mtd, to, false, ops);
>
> - return mtd_write_oob_std(mtd, to, ops);
> + ret = mtd_write_oob_std(mtd, to, ops);
> +
> + return ret;
Ditto, you can keep the 'return mtd_write_oob_std(mtd, to, ops);' here.
> }
> EXPORT_SYMBOL_GPL(mtd_write_oob);
> +static inline void mtd_start_access(struct mtd_info *master)
> +{
> + WARN_ON_ONCE(master != mtd_get_master(master));
> +
> + /*
> + * Don't take the suspend_lock on devices that don't
> + * implement the suspend hook. Otherwise, lockdep will
> + * complain about nested locks when trying to suspend MTD
> + * partitions or MTD devices created by gluebi which are
> + * backed by real devices.
> + */
> + if (!master->_suspend)
> + return;
> +
> + /*
> + * Wait until the device is resumed. Should we have a
> + * non-blocking mode here?
> + */
> + while (1) {
> + down_read(&master->master.suspend_lock);
> + if (!master->master.suspended)
> + return;
> +
> + up_read(&master->master.suspend_lock);
> + wait_event(master->master.resume_wq, master->master.suspended == 0);
Please keep the tests consistent:
wait_event(master->master.resume_wq, !master->master.suspended);
> + }
> +}
> +
On Wed, Oct 20, 2021 at 10:57:43AM +0200, Boris Brezillon wrote:
> On Wed, 20 Oct 2021 10:45:33 +0200
> Sean Nyekjaer <[email protected]> wrote:
>
> > Access is protected in upper MTD layer when MTD devices are suspended.
>
> I think it deserves more explanation.
>
Access is protected in upper MTD layer when MTD devices are suspended.
Commit ("mtd: core: protect access to MTD devices while in suspend")
introduces access protection, so it's safe to remove suspended checks.