[Devel] [PATCH RHEL7 COMMIT] ploop: allow to set discard granularity and alignment attributes

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-693.17.1.vz7.43.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-693.17.1.vz7.43.5
------>
commit b1000c102485989296264158dd54572789101bdd
Author: Andrei Vagin <avagin at openvz.org>
Date:   Thu Feb 15 17:34:47 2018 +0300

    ploop: allow to set discard granularity and alignment attributes
    
    Different backing stores can have different values for these parameters.
    
    Signed-off-by: Andrei Vagin <avagin at openvz.org>
---
 drivers/block/ploop/sysfs.c | 48 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/drivers/block/ploop/sysfs.c b/drivers/block/ploop/sysfs.c
index acd18ff7a426..835558a29777 100644
--- a/drivers/block/ploop/sysfs.c
+++ b/drivers/block/ploop/sysfs.c
@@ -362,6 +362,51 @@ static int store_aborted(struct ploop_device * plo, u32 val)
 	return 0;
 }
 
+static u32 show_discard_granularity(struct ploop_device * plo)
+{
+	return plo->queue->limits.discard_granularity;
+}
+
+static int store_discard_granularity(struct ploop_device * plo, u32 val)
+{
+	int q = ilog2(val);
+
+	/* look at kaio_fill_zero_submit */
+	if (1 << q != val || val > PAGE_SIZE || val < 512)
+		return -EINVAL;
+
+	plo->queue->limits.discard_granularity = val;
+	return 0;
+}
+
+static u32 show_discard_alignment(struct ploop_device * plo)
+{
+	return plo->queue->limits.discard_alignment;
+}
+
+static int store_discard_alignment(struct ploop_device * plo, u32 val)
+{
+	int q = ilog2(val);
+
+	/* look at kaio_fill_zero_submit */
+	if (1 << q != val || val > PAGE_SIZE || val < 512)
+		return -EINVAL;
+
+	plo->queue->limits.discard_alignment = val;
+	return 0;
+}
+
+static u32 show_discard_zeroes_data(struct ploop_device * plo)
+{
+	return plo->queue->limits.discard_zeroes_data;
+}
+
+static int store_discard_zeroes_data(struct ploop_device * plo, u32 val)
+{
+	plo->queue->limits.discard_zeroes_data = !!val;
+	return 0;
+}
+
 static u32 show_top(struct ploop_device * plo)
 {
 	int top = -1;
@@ -550,6 +595,9 @@ static struct attribute *state_attributes[] = {
 	_A(blockable_reqs),
 	_A(blocked_bios),
 	_A(freeze_state),
+	_A2(discard_granularity),
+	_A2(discard_alignment),
+	_A2(discard_zeroes_data),
 	NULL
 };