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mtd: spi-nor: fix memory leak when using debugfs_lookup()

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When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time.  To solve this, remove the
lookup and create the directory on the first device found, and then
remove it when the module is unloaded.

Cc: Tudor Ambarus <tudor.ambarus@microchip.com>
Cc: Pratyush Yadav <pratyush@kernel.org>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Cc: linux-mtd@lists.infradead.org
Reviewed-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20230208160230.2179905-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Greg Kroah-Hartman 2023-02-08 17:02:30 +01:00
parent fe15c26ee2
commit ec738ca127
3 changed files with 23 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
drivers/mtd/spi-nor/core.c
View File

@ -3343,7 +3343,19 @@ static struct spi_mem_driver spi_nor_driver = {
.remove = spi_nor_remove, .remove = spi_nor_remove,
.shutdown = spi_nor_shutdown, .shutdown = spi_nor_shutdown,
}; };
module_spi_mem_driver(spi_nor_driver);
static int __init spi_nor_module_init(void)
{
return spi_mem_driver_register(&spi_nor_driver);
}
module_init(spi_nor_module_init);
static void __exit spi_nor_module_exit(void)
{
spi_mem_driver_unregister(&spi_nor_driver);
spi_nor_debugfs_shutdown();
}
module_exit(spi_nor_module_exit);
MODULE_LICENSE("GPL v2"); MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Huang Shijie <shijie8@gmail.com>"); MODULE_AUTHOR("Huang Shijie <shijie8@gmail.com>");

2
drivers/mtd/spi-nor/core.h
View File

@ -711,8 +711,10 @@ static inline struct spi_nor *mtd_to_spi_nor(struct mtd_info *mtd)
#ifdef CONFIG_DEBUG_FS #ifdef CONFIG_DEBUG_FS
void spi_nor_debugfs_register(struct spi_nor *nor); void spi_nor_debugfs_register(struct spi_nor *nor);
void spi_nor_debugfs_shutdown(void);
#else #else
static inline void spi_nor_debugfs_register(struct spi_nor *nor) {} static inline void spi_nor_debugfs_register(struct spi_nor *nor) {}
static inline void spi_nor_debugfs_shutdown(void) {}
#endif #endif
#endif /* __LINUX_MTD_SPI_NOR_INTERNAL_H */ #endif /* __LINUX_MTD_SPI_NOR_INTERNAL_H */

11
drivers/mtd/spi-nor/debugfs.c
View File

@ -226,13 +226,13 @@ static void spi_nor_debugfs_unregister(void *data)
nor->debugfs_root = NULL; nor->debugfs_root = NULL;
} }
static struct dentry *rootdir;
void spi_nor_debugfs_register(struct spi_nor *nor) void spi_nor_debugfs_register(struct spi_nor *nor)
{ {
struct dentry *rootdir, *d; struct dentry *d;
int ret; int ret;
/* Create rootdir once. Will never be deleted again. */
rootdir = debugfs_lookup(SPI_NOR_DEBUGFS_ROOT, NULL);
if (!rootdir) if (!rootdir)
rootdir = debugfs_create_dir(SPI_NOR_DEBUGFS_ROOT, NULL); rootdir = debugfs_create_dir(SPI_NOR_DEBUGFS_ROOT, NULL);
@ -247,3 +247,8 @@ void spi_nor_debugfs_register(struct spi_nor *nor)
debugfs_create_file("capabilities", 0444, d, nor, debugfs_create_file("capabilities", 0444, d, nor,
&spi_nor_capabilities_fops); &spi_nor_capabilities_fops);
} }
void spi_nor_debugfs_shutdown(void)
{
debugfs_remove(rootdir);
}