This is a note to let you know that I've just added the patch titled
mtd: Avoid probe failures when mtd->dbg.dfs_dir is invalid
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mtd-avoid-probe-failures-when-mtd-dbg.dfs_dir-is-invalid.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 1530578abdac4edce9244c7a1962ded3ffdb58ce Mon Sep 17 00:00:00 2001
From: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
Date: Sat, 11 Nov 2017 16:08:34 +0100
Subject: mtd: Avoid probe failures when mtd->dbg.dfs_dir is invalid
From: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
commit 1530578abdac4edce9244c7a1962ded3ffdb58ce upstream.
Commit e8e3edb95ce6 ("mtd: create per-device and module-scope debugfs
entries") tried to make MTD related debugfs stuff consistent across the
MTD framework by creating a root <debugfs>/mtd/ directory containing
one directory per MTD device.
The problem is that, by default, the MTD layer only registers the
master device if no partitions are defined for this master. This
behavior breaks all drivers that expect mtd->dbg.dfs_dir to be filled
correctly after calling mtd_device_register() in order to add their own
debugfs entries.
The only way we can force all MTD masters to be registered no matter if
they expose partitions or not is by enabling the
CONFIG_MTD_PARTITIONED_MASTER option.
In such situations, there's no other solution but to accept skipping
debugfs initialization when dbg.dfs_dir is invalid, and when this
happens, inform the user that he should consider enabling
CONFIG_MTD_PARTITIONED_MASTER.
Fixes: e8e3edb95ce6 ("mtd: create per-device and module-scope debugfs entries")
Cc: Mario J. Rugiero <mrugiero@xxxxxxxxx>
Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
Reported-by: Richard Weinberger <richard@xxxxxx>
Signed-off-by: Richard Weinberger <richard@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/mtd/devices/docg3.c | 7 ++++++-
drivers/mtd/nand/nandsim.c | 13 +++++++++----
2 files changed, 15 insertions(+), 5 deletions(-)
--- a/drivers/mtd/devices/docg3.c
+++ b/drivers/mtd/devices/docg3.c
@@ -1814,8 +1814,13 @@ static void __init doc_dbg_register(stru
struct dentry *root = floor->dbg.dfs_dir;
struct docg3 *docg3 = floor->priv;
- if (IS_ERR_OR_NULL(root))
+ if (IS_ERR_OR_NULL(root)) {
+ if (IS_ENABLED(CONFIG_DEBUG_FS) &&
+ !IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER))
+ dev_warn(floor->dev.parent,
+ "CONFIG_MTD_PARTITIONED_MASTER must be enabled to expose debugfs stuff\n");
return;
+ }
debugfs_create_file("docg3_flashcontrol", S_IRUSR, root, docg3,
&flashcontrol_fops);
--- a/drivers/mtd/nand/nandsim.c
+++ b/drivers/mtd/nand/nandsim.c
@@ -520,11 +520,16 @@ static int nandsim_debugfs_create(struct
struct dentry *root = nsmtd->dbg.dfs_dir;
struct dentry *dent;
- if (!IS_ENABLED(CONFIG_DEBUG_FS))
+ /*
+ * Just skip debugfs initialization when the debugfs directory is
+ * missing.
+ */
+ if (IS_ERR_OR_NULL(root)) {
+ if (IS_ENABLED(CONFIG_DEBUG_FS) &&
+ !IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER))
+ NS_WARN("CONFIG_MTD_PARTITIONED_MASTER must be enabled to expose debugfs stuff\n");
return 0;
-
- if (IS_ERR_OR_NULL(root))
- return -1;
+ }
dent = debugfs_create_file("nandsim_wear_report", S_IRUSR,
root, dev, &dfs_fops);
Patches currently in stable-queue which might be from boris.brezillon@xxxxxxxxxxxxxxxxxx are
queue-4.14/mtd-nand-fix-writing-mtdoops-to-nand-flash.patch
queue-4.14/mtd-nand-export-nand_reset-symbol.patch
queue-4.14/mtd-nand-mtk-fix-infinite-ecc-decode-irq-issue.patch
queue-4.14/mtd-nand-atmel-actually-use-the-pm-ops.patch
queue-4.14/mtd-nand-omap2-fix-subpage-write.patch
queue-4.14/mtd-avoid-probe-failures-when-mtd-dbg.dfs_dir-is-invalid.patch