kernel: add linux 4.9 support

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Tim Harvey <tharvey@gateworks.com> [fixes]

1 files changed, 66 insertions, 0 deletions

diff --git a/target/linux/generic/patches-4.9/030-02-ubifs-Use-dirty_writeback_interval-value-for-wbuf-ti.patch b/target/linux/generic/patches-4.9/030-02-ubifs-Use-dirty_writeback_interval-value-for-wbuf-ti.patch
new file mode 100644
index 0000000000..96fa441132
--- /dev/null
+++ b/target/linux/generic/patches-4.9/030-02-ubifs-Use-dirty_writeback_interval-value-for-wbuf-ti.patch
@@ -0,0 +1,66 @@
+From 1b7fc2c0069f3864a3dda15430b7aded31c0bfcc Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Tue, 20 Sep 2016 10:36:15 +0200
+Subject: [PATCH] ubifs: Use dirty_writeback_interval value for wbuf timer
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Right now wbuf timer has hardcoded timeouts and there is no place for
+manual adjustments. Some projects / cases many need that though. Few
+file systems allow doing that by respecting dirty_writeback_interval
+that can be set using sysctl (dirty_writeback_centisecs).
+
+Lowering dirty_writeback_interval could be some way of dealing with user
+space apps lacking proper fsyncs. This is definitely *not* a perfect
+solution but we don't have ideal (user space) world. There were already
+advanced discussions on this matter, mostly when ext4 was introduced and
+it wasn't behaving as ext3. Anyway, the final decision was to add some
+hacks to the ext4, as trying to fix whole user space or adding new API
+was pointless.
+
+We can't (and shouldn't?) just follow ext4. We can't e.g. sync on close
+as this would cause too many commits and flash wearing. On the other
+hand we still should allow some trade-off between -o sync and default
+wbuf timeout. Respecting dirty_writeback_interval should allow some sane
+cutomizations if used warily.
+
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
+Signed-off-by: Richard Weinberger <richard@nod.at>
+---
+ fs/ubifs/io.c    | 8 ++++----
+ fs/ubifs/ubifs.h | 4 ----
+ 2 files changed, 4 insertions(+), 8 deletions(-)
+
+--- a/fs/ubifs/io.c
++++ b/fs/ubifs/io.c
+@@ -452,11 +452,11 @@ static enum hrtimer_restart wbuf_timer_c
+  */
+ static void new_wbuf_timer_nolock(struct ubifs_wbuf *wbuf)
+ {
+-	ktime_t softlimit = ktime_set(WBUF_TIMEOUT_SOFTLIMIT, 0);
+-	unsigned long long delta;
++	ktime_t softlimit = ms_to_ktime(dirty_writeback_interval * 10);
++	unsigned long long delta = dirty_writeback_interval;
+ 
+-	delta = WBUF_TIMEOUT_HARDLIMIT - WBUF_TIMEOUT_SOFTLIMIT;
+-	delta *= 1000000000ULL;
++	/* centi to milli, milli to nano, then 10% */
++	delta *= 10ULL * NSEC_PER_MSEC / 10ULL;
+ 
+ 	ubifs_assert(!hrtimer_active(&wbuf->timer));
+ 	ubifs_assert(delta <= ULONG_MAX);
+--- a/fs/ubifs/ubifs.h
++++ b/fs/ubifs/ubifs.h
+@@ -83,10 +83,6 @@
+  */
+ #define BGT_NAME_PATTERN "ubifs_bgt%d_%d"
+ 
+-/* Write-buffer synchronization timeout interval in seconds */
+-#define WBUF_TIMEOUT_SOFTLIMIT 3
+-#define WBUF_TIMEOUT_HARDLIMIT 5
+-
+ /* Maximum possible inode number (only 32-bit inodes are supported now) */
+ #define MAX_INUM 0xFFFFFFFF
+