Added BFQ patch fix

3 files changed, 45 insertions, 2 deletions

diff --git a/.SRCINFO b/.SRCINFO
index 5147c7c5ee07..7911b1a4deda 100644
--- a/.SRCINFO
+++ b/.SRCINFO
@@ -1,6 +1,6 @@
 pkgbase = linux-covolunablu-gaming
 	pkgver = 4.15.14
-	pkgrel = 1
+	pkgrel = 2
 	url = https://www.kernel.org/
 	arch = x86_64
 	license = GPL2
@@ -22,6 +22,7 @@ pkgbase = linux-covolunablu-gaming
 	source = 0001-add-sysctl-to-disallow-unprivileged-CLONE_NEWUSER-by.patch
 	source = 0002-drm-i915-edp-Only-use-the-alternate-fixed-mode-if-it.patch
 	source = bfq-default.patch
+	source = bfq-lock-division-zero.patch
 	source = https://raw.githubusercontent.com/ValveSoftware/steamos_kernel/c4948d923637a956853df0e85a6d530e483bdffa/drivers/input/joystick/xpad.c
 	validpgpkeys = ABAF11C65A2970B130ABE3C479BE3E4300411886
 	validpgpkeys = 647F28654894E3BD457199BE38DBBDC86092693E
@@ -36,6 +37,7 @@ pkgbase = linux-covolunablu-gaming
 	sha256sums = 19b17156ea5aec86e4eb87fc855789375a5184faf564b4ac2cd0f279de7b3bf9
 	sha256sums = f49e23e2a00357f8a5f6cc5caadd56a4df2b0a3e2b53d76a514ca508f25a62a7
 	sha256sums = a20f72660076bc5f73404800da9bc52ceb592bdfbdab19438d66da8c01edc4f4
+	sha256sums = 2a40a1906c5bef180035c8af21c38c1f364a81f38507b684058803b3fa9fcfd6
 	sha256sums = 851b79826c1695acf93faffb17bcb420c11d12cfa96ac6b5082e4306c2d8fb55
 
 pkgname = linux-covolunablu-gaming
diff --git a/PKGBUILD b/PKGBUILD
index 5cf259829399..d89053be1717 100644
--- a/PKGBUILD
+++ b/PKGBUILD
@@ -6,7 +6,7 @@
 pkgbase=linux-covolunablu-gaming
 _srcname=linux-4.15
 pkgver=4.15.14
-pkgrel=1
+pkgrel=2
 arch=('x86_64')
 url="https://www.kernel.org/"
 license=('GPL2')
@@ -29,6 +29,7 @@ source=(
   0001-add-sysctl-to-disallow-unprivileged-CLONE_NEWUSER-by.patch
   0002-drm-i915-edp-Only-use-the-alternate-fixed-mode-if-it.patch
   bfq-default.patch
+  bfq-lock-division-zero.patch
   https://raw.githubusercontent.com/ValveSoftware/steamos_kernel/c4948d923637a956853df0e85a6d530e483bdffa/drivers/input/joystick/xpad.c
 )
 validpgpkeys=(
@@ -47,6 +48,7 @@ sha256sums=('5a26478906d5005f4f809402e981518d2b8844949199f60c4b6e1f986ca2a769'
             '19b17156ea5aec86e4eb87fc855789375a5184faf564b4ac2cd0f279de7b3bf9'
             'f49e23e2a00357f8a5f6cc5caadd56a4df2b0a3e2b53d76a514ca508f25a62a7'
             'a20f72660076bc5f73404800da9bc52ceb592bdfbdab19438d66da8c01edc4f4'
+            '2a40a1906c5bef180035c8af21c38c1f364a81f38507b684058803b3fa9fcfd6'
             '851b79826c1695acf93faffb17bcb420c11d12cfa96ac6b5082e4306c2d8fb55'
 )
 
@@ -71,6 +73,10 @@ prepare() {
   # use bfq as default scheduler
   patch -p1 -i ../bfq-default.patch
 
+  # fix for bfq blocking requests for slow devices
+  # https://www.spinics.net/lists/kernel/msg2739205.html
+  patch -p1 -i ../bfq-lock-division-zero.patch
+
   # use steamos version of xpad
   cp "${srcdir}/xpad.c" ./drivers/input/joystick/xpad.c
 
diff --git a/bfq-lock-division-zero.patch b/bfq-lock-division-zero.patch
new file mode 100644
index 000000000000..e8d8727d5117
--- /dev/null
+++ b/bfq-lock-division-zero.patch
@@ -0,0 +1,35 @@
+Rate should never overflow or become zero because it is used as divider.
+This patch accumulates it with saturation.
+
+Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
+---
+ block/bfq-iosched.c |    8 +++++---
+ 1 file changed, 5 insertions(+), 3 deletions(-)
+
+diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
+index aeca22d91101..a236c8d541b5 100644
+--- a/block/bfq-iosched.c
++++ b/block/bfq-iosched.c
+@@ -2546,7 +2546,8 @@ static void bfq_reset_rate_computation(struct bfq_data *bfqd,
+ 
+ static void bfq_update_rate_reset(struct bfq_data *bfqd, struct request *rq)
+ {
+-	u32 rate, weight, divisor;
++	u32 weight, divisor;
++	u64 rate;
+ 
+ 	/*
+ 	 * For the convergence property to hold (see comments on
+@@ -2634,9 +2635,10 @@ static void bfq_update_rate_reset(struct bfq_data *bfqd, struct request *rq)
+ 	 */
+ 	bfqd->peak_rate *= divisor-1;
+ 	bfqd->peak_rate /= divisor;
+-	rate /= divisor; /* smoothing constant alpha = 1/divisor */
++	do_div(rate, divisor);	/* smoothing constant alpha = 1/divisor */
+ 
+-	bfqd->peak_rate += rate;
++	/* rate should never overlow or become zero */
++	bfqd->peak_rate = clamp_t(u64, rate + bfqd->peak_rate, 1, U32_MAX);
+ 	update_thr_responsiveness_params(bfqd);
+ 
+ reset_computation: