diff options
| author | Alexander Usyskin <alexander.usyskin@intel.com> | 2023-06-20 16:19:05 +0300 |
|---|---|---|
| committer | Miquel Raynal <miquel.raynal@bootlin.com> | 2023-07-12 14:30:10 +0300 |
| commit | 79c4a56250216991f1d965ee26dcd273376e4e91 (patch) | |
| tree | 202bfcacd24d276d900ba9f14ee131682743f5d8 /drivers/mtd/mtdcore.c | |
| parent | 19bfa9ebebb5ec0695def57eb1d80de7e9cab369 (diff) | |
| download | linux-79c4a56250216991f1d965ee26dcd273376e4e91.tar.xz | |
mtd: call external _get and _put in right order
MTD provider provides mtd_info object to mtd subsystem.
With kref patch the mtd_info object can be alive after
provider released mtd device.
Fix calling order in _get and _put functions to allow
mtd provider to safely alloc and release mtd object.
Execute:
1) call external _get
2) get_module
3) add internal kref
in the get function and opposite order in the put one.
The _put_device callback should be the last in put
as the master struct memory may be freed in this callback.
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20230620131905.648089-3-alexander.usyskin@intel.com
Diffstat (limited to 'drivers/mtd/mtdcore.c')
| -rw-r--r-- | drivers/mtd/mtdcore.c | 28 |
1 files changed, 14 insertions, 14 deletions
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c index 6dbd596a1129..2466ea466466 100644 --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -1229,21 +1229,20 @@ int __get_mtd_device(struct mtd_info *mtd) struct mtd_info *master = mtd_get_master(mtd); int err; - if (!try_module_get(master->owner)) - return -ENODEV; - - kref_get(&mtd->refcnt); - if (master->_get_device) { err = master->_get_device(mtd); - - if (err) { - kref_put(&mtd->refcnt, mtd_device_release); - module_put(master->owner); + if (err) return err; - } } + if (!try_module_get(master->owner)) { + if (master->_put_device) + master->_put_device(master); + return -ENODEV; + } + + kref_get(&mtd->refcnt); + while (mtd->parent) { if (IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER) || mtd->parent != master) kref_get(&mtd->parent->refcnt); @@ -1340,13 +1339,14 @@ void __put_mtd_device(struct mtd_info *mtd) mtd = parent; } - if (master->_put_device) - master->_put_device(master); + if (IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER)) + kref_put(&master->refcnt, mtd_device_release); module_put(master->owner); - if (IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER)) - kref_put(&master->refcnt, mtd_device_release); + /* must be the last as master can be freed in the _put_device */ + if (master->_put_device) + master->_put_device(master); } EXPORT_SYMBOL_GPL(__put_mtd_device); |