sys-kernel/zfs-dkms : add kernel 5.5 compat

2 files changed, 138 insertions, 0 deletions

diff --git a/sys-kernel/zfs-dkms/files/2fcab8795c7c493845bfa277d44bc443802000b8.patch b/sys-kernel/zfs-dkms/files/2fcab8795c7c493845bfa277d44bc443802000b8.patch
new file mode 100644
index 00000000..f636e87f
--- /dev/null
+++ b/sys-kernel/zfs-dkms/files/2fcab8795c7c493845bfa277d44bc443802000b8.patch
@@ -0,0 +1,136 @@
+From 2fcab8795c7c493845bfa277d44bc443802000b8 Mon Sep 17 00:00:00 2001
+From: Brian Behlendorf <behlendorf1@llnl.gov>
+Date: Fri, 28 Feb 2020 08:58:39 -0800
+Subject: [PATCH] Linux 5.5 compat: blkg_tryget()
+
+Commit https://github.com/torvalds/linux/commit/9e8d42a0f accidentally
+converted the static inline function blkg_tryget() to GPL-only for
+kernels built with CONFIG_PREEMPT_RCU=y and CONFIG_BLK_CGROUP=y.
+
+Resolve the build issue by providing our own equivalent functionality
+when needed which uses rcu_read_lock_sched() internally as before.
+
+Reviewed-by: Tony Hutter <hutter2@llnl.gov>
+Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
+Closes #9745
+Closes #10072
+---
+ config/kernel-blkg-tryget.m4 | 37 ++++++++++++++++++++++++++++++++++++
+ config/kernel.m4             |  2 ++
+ module/zfs/vdev_disk.c       | 32 ++++++++++++++++++++++++++++++-
+ 3 files changed, 70 insertions(+), 1 deletion(-)
+ create mode 100644 config/kernel-blkg-tryget.m4
+
+diff --git a/config/kernel-blkg-tryget.m4 b/config/kernel-blkg-tryget.m4
+new file mode 100644
+index 00000000000..fb831ca3b3e
+--- /dev/null
++++ b/config/kernel-blkg-tryget.m4
+@@ -0,0 +1,37 @@
++dnl #
++dnl # Linux 5.5 API,
++dnl #
++dnl # The Linux 5.5 kernel updated percpu_ref_tryget() which is inlined by
++dnl # blkg_tryget() to use rcu_read_lock() instead of rcu_read_lock_sched().
++dnl # As a side effect the function was converted to GPL-only.
++dnl #
++AC_DEFUN([ZFS_AC_KERNEL_SRC_BLKG_TRYGET], [
++	ZFS_LINUX_TEST_SRC([blkg_tryget], [
++		#include <linux/blk-cgroup.h>
++		#include <linux/bio.h>
++		#include <linux/fs.h>
++	],[
++		struct blkcg_gq blkg __attribute__ ((unused));
++		bool rc __attribute__ ((unused));
++		rc = blkg_tryget(&blkg);
++	], [], [$ZFS_META_LICENSE])
++])
++
++AC_DEFUN([ZFS_AC_KERNEL_BLKG_TRYGET], [
++	AC_MSG_CHECKING([whether blkg_tryget() is available])
++	ZFS_LINUX_TEST_RESULT([blkg_tryget], [
++		AC_MSG_RESULT(yes)
++		AC_DEFINE(HAVE_BLKG_TRYGET, 1, [blkg_tryget() is available])
++
++		AC_MSG_CHECKING([whether blkg_tryget() is GPL-only])
++		ZFS_LINUX_TEST_RESULT([blkg_tryget_license], [
++			AC_MSG_RESULT(no)
++		],[
++			AC_MSG_RESULT(yes)
++			AC_DEFINE(HAVE_BLKG_TRYGET_GPL_ONLY, 1,
++			    [blkg_tryget() GPL-only])
++		])
++	],[
++		AC_MSG_RESULT(no)
++	])
++])
+diff --git a/config/kernel.m4 b/config/kernel.m4
+index dce619729d4..bea6f9b1bbf 100644
+--- a/config/kernel.m4
++++ b/config/kernel.m4
+@@ -70,6 +70,7 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_SRC], [
+ 	ZFS_AC_KERNEL_SRC_BIO_BI_STATUS
+ 	ZFS_AC_KERNEL_SRC_BIO_RW_BARRIER
+ 	ZFS_AC_KERNEL_SRC_BIO_RW_DISCARD
++	ZFS_AC_KERNEL_SRC_BLKG_TRYGET
+ 	ZFS_AC_KERNEL_SRC_BLK_QUEUE_BDI
+ 	ZFS_AC_KERNEL_SRC_BLK_QUEUE_DISCARD
+ 	ZFS_AC_KERNEL_SRC_BLK_QUEUE_SECURE_ERASE
+@@ -186,6 +187,7 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_RESULT], [
+ 	ZFS_AC_KERNEL_BIO_BI_STATUS
+ 	ZFS_AC_KERNEL_BIO_RW_BARRIER
+ 	ZFS_AC_KERNEL_BIO_RW_DISCARD
++	ZFS_AC_KERNEL_BLKG_TRYGET
+ 	ZFS_AC_KERNEL_BLK_QUEUE_BDI
+ 	ZFS_AC_KERNEL_BLK_QUEUE_DISCARD
+ 	ZFS_AC_KERNEL_BLK_QUEUE_SECURE_ERASE
+diff --git a/module/zfs/vdev_disk.c b/module/zfs/vdev_disk.c
+index 661f0f1b727..8544bb8ffb6 100644
+--- a/module/zfs/vdev_disk.c
++++ b/module/zfs/vdev_disk.c
+@@ -473,6 +473,36 @@ vdev_submit_bio_impl(struct bio *bio)
+ 
+ #ifdef HAVE_BIO_SET_DEV
+ #if defined(CONFIG_BLK_CGROUP) && defined(HAVE_BIO_SET_DEV_GPL_ONLY)
++/*
++ * The Linux 5.5 kernel updated percpu_ref_tryget() which is inlined by
++ * blkg_tryget() to use rcu_read_lock() instead of rcu_read_lock_sched().
++ * As a side effect the function was converted to GPL-only.  Define our
++ * own version when needed which uses rcu_read_lock_sched().
++ */
++#if defined(HAVE_BLKG_TRYGET_GPL_ONLY)
++static inline bool
++vdev_blkg_tryget(struct blkcg_gq *blkg)
++{
++	struct percpu_ref *ref = &blkg->refcnt;
++	unsigned long __percpu *count;
++	bool rc;
++
++	rcu_read_lock_sched();
++
++	if (__ref_is_percpu(ref, &count)) {
++		this_cpu_inc(*count);
++		rc = true;
++	} else {
++		rc = atomic_long_inc_not_zero(&ref->count);
++	}
++
++	rcu_read_unlock_sched();
++
++	return (rc);
++}
++#elif defined(HAVE_BLKG_TRYGET)
++#define	vdev_blkg_tryget(bg)	blkg_tryget(bg)
++#endif
+ /*
+  * The Linux 5.0 kernel updated the bio_set_dev() macro so it calls the
+  * GPL-only bio_associate_blkg() symbol thus inadvertently converting
+@@ -487,7 +517,7 @@ vdev_bio_associate_blkg(struct bio *bio)
+ 	ASSERT3P(q, !=, NULL);
+ 	ASSERT3P(bio->bi_blkg, ==, NULL);
+ 
+-	if (q->root_blkg && blkg_tryget(q->root_blkg))
++	if (q->root_blkg && vdev_blkg_tryget(q->root_blkg))
+ 		bio->bi_blkg = q->root_blkg;
+ }
+ #define	bio_associate_blkg vdev_bio_associate_blkg
diff --git a/sys-kernel/zfs-dkms/zfs-dkms-0.8.3.ebuild b/sys-kernel/zfs-dkms/zfs-dkms-0.8.3-r1.ebuild
index 7e448719..09d17241 100644
--- a/sys-kernel/zfs-dkms/zfs-dkms-0.8.3.ebuild
+++ b/sys-kernel/zfs-dkms/zfs-dkms-0.8.3-r1.ebuild
@@ -20,6 +20,8 @@ IUSE=""
 DEPEND="sys-kernel/dkms"
 RDEPEND="${DEPEND}"
 
+PATCHES=( "${FILESDIR}"/2fcab8795c7c493845bfa277d44bc443802000b8.patch )
+
 S="${WORKDIR}/${MY_P}"
 
 src_configure() {