bybrooklyn/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-04-18 06:44:00 -04:00
Code Issues Packages Projects Releases Wiki Activity

mtd: call external _get and _put in right order

Browse Source 
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
This commit is contained in:
Alexander Usyskin
2023-06-20 16:19:05 +03:00
committed by Miquel Raynal
parent 19bfa9ebeb
commit 79c4a56250
1 changed files with 14 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

28
drivers/mtd/mtdcore.c
View File

@@ -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);