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

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>

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index 0a78045ca1d94ea184d295bfdb3af8bb1f41894b..522d375aeccff6be0397ce2df10e33261358307e 100644 (file)
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -3343,7 +3343,19 @@ static struct spi_mem_driver spi_nor_driver = {
        .remove = spi_nor_remove,
        .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_AUTHOR("Huang Shijie <shijie8@gmail.com>");

diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
index 25423225c29d33f1817a1872106c54e4a00ad5c8..e0cc42a4a0c8410a0148a649b58684ae6eb8940d 100644 (file)
--- a/drivers/mtd/spi-nor/core.h
+++ b/drivers/mtd/spi-nor/core.h
@@ -711,8 +711,10 @@ static inline struct spi_nor *mtd_to_spi_nor(struct mtd_info *mtd)
 
 #ifdef CONFIG_DEBUG_FS
 void spi_nor_debugfs_register(struct spi_nor *nor);
+void spi_nor_debugfs_shutdown(void);
 #else
 static inline void spi_nor_debugfs_register(struct spi_nor *nor) {}
+static inline void spi_nor_debugfs_shutdown(void) {}
 #endif
 
 #endif /* __LINUX_MTD_SPI_NOR_INTERNAL_H */

diff --git a/drivers/mtd/spi-nor/debugfs.c b/drivers/mtd/spi-nor/debugfs.c
index 845b78c7ecc7a27f6fa18a6afd982adf63a0fea6..fc7ad203df12802b0f5aa5c386a5077b3844143e 100644 (file)
--- a/drivers/mtd/spi-nor/debugfs.c
+++ b/drivers/mtd/spi-nor/debugfs.c
@@ -226,13 +226,13 @@ static void spi_nor_debugfs_unregister(void *data)
        nor->debugfs_root = NULL;
 }
 
+static struct dentry *rootdir;
+
 void spi_nor_debugfs_register(struct spi_nor *nor)
 {
-       struct dentry *rootdir, *d;
+       struct dentry *d;
        int ret;
 
-       /* Create rootdir once. Will never be deleted again. */
-       rootdir = debugfs_lookup(SPI_NOR_DEBUGFS_ROOT, NULL);
        if (!rootdir)
                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,
                            &spi_nor_capabilities_fops);
 }
+
+void spi_nor_debugfs_shutdown(void)
+{
+       debugfs_remove(rootdir);
+}