Update Linux to v5.4.148

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz

Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/Documentation/filesystems/affs.txt b/Documentation/filesystems/affs.txt
index 71b63c2..a8f1a58 100644
--- a/Documentation/filesystems/affs.txt
+++ b/Documentation/filesystems/affs.txt
@@ -93,13 +93,15 @@
 
   - R maps to r for user, group and others. On directories, R implies x.
 
-  - If both W and D are allowed, w will be set.
+  - W maps to w.
 
   - E maps to x.
 
-  - H and P are always retained and ignored under Linux.
+  - D is ignored.
 
-  - A is always reset when a file is written to.
+  - H, S and P are always retained and ignored under Linux.
+
+  - A is cleared when a file is written to.
 
 User id and group id will be used unless set[gu]id are given as mount
 options. Since most of the Amiga file systems are single user systems
@@ -111,11 +113,13 @@
 
 The Linux rwxrwxrwx file mode is handled as follows:
 
-  - r permission will set R for user, group and others.
+  - r permission will allow R for user, group and others.
 
-  - w permission will set W and D for user, group and others.
+  - w permission will allow W for user, group and others.
 
-  - x permission of the user will set E for plain files.
+  - x permission of the user will allow E for plain files.
+
+  - D will be allowed for user, group and others.
 
   - All other flags (suid, sgid, ...) are ignored and will
     not be retained.
diff --git a/Documentation/filesystems/porting.rst b/Documentation/filesystems/porting.rst
index f185060..26c0939 100644
--- a/Documentation/filesystems/porting.rst
+++ b/Documentation/filesystems/porting.rst
@@ -850,3 +850,11 @@
 d_alloc_pseudo() is internal-only; uses outside of alloc_file_pseudo() are
 very suspect (and won't work in modules).  Such uses are very likely to
 be misspelled d_alloc_anon().
+
+---
+
+**mandatory**
+
+[should've been added in 2016] stale comment in finish_open() nonwithstanding,
+failure exits in ->atomic_open() instances should *NOT* fput() the file,
+no matter what.  Everything is handled by the caller.
diff --git a/Documentation/filesystems/seq_file.txt b/Documentation/filesystems/seq_file.txt
index d412b23..7cf7143 100644
--- a/Documentation/filesystems/seq_file.txt
+++ b/Documentation/filesystems/seq_file.txt
@@ -192,6 +192,12 @@
 is a reasonable thing to do. The seq_file code will also avoid taking any
 other locks while the iterator is active.
 
+The iterater value returned by start() or next() is guaranteed to be
+passed to a subsequent next() or stop() call.  This allows resources
+such as locks that were taken to be reliably released.  There is *no*
+guarantee that the iterator will be passed to show(), though in practice
+it often will be.
+
 
 Formatted output
 
diff --git a/Documentation/filesystems/sysfs.txt b/Documentation/filesystems/sysfs.txt
index ddf15b1..33ec0a0 100644
--- a/Documentation/filesystems/sysfs.txt
+++ b/Documentation/filesystems/sysfs.txt
@@ -232,12 +232,10 @@
   is 4096. 
 
 - show() methods should return the number of bytes printed into the
-  buffer. This is the return value of scnprintf().
+  buffer.
 
-- show() must not use snprintf() when formatting the value to be
-  returned to user space. If you can guarantee that an overflow
-  will never happen you can use sprintf() otherwise you must use
-  scnprintf().
+- show() should only use sysfs_emit() or sysfs_emit_at() when formatting
+  the value to be returned to user space.
 
 - store() should return the number of bytes used from the buffer. If the
   entire buffer has been used, just return the count argument.