From 77aa3f6374e13c01bd79a851bc69b8402dffea13 Mon Sep 17 00:00:00 2001
From: Mike Christie <mchristi@redhat.com>
Date: Tue, 28 Nov 2017 12:40:35 -0600
Subject: [PATCH] tcmu: fix free block calculation
Git-commit: 3c0f26ff9d040c6193b33689bbc03103854dba4d
Patch-mainline: v4.16-rc1
References: bsc#1118978
The blocks_left calculation does not account for free blocks
between 0 and thresh, so we could be queueing/waiting when
there are enough blocks free.
This has us add in the blocks between 0 and thresh as well as
at the end from thresh to DATA_BLOCK_BITS.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Acked-by: David Disseldorp <ddiss@suse.de>
---
drivers/target/target_core_user.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
index 859ef744bd18..bfe8799b0206 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -642,7 +642,7 @@ static void gather_data_area(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
static inline size_t spc_bitmap_free(unsigned long *bitmap, uint32_t thresh)
{
- return DATA_BLOCK_SIZE * (thresh - bitmap_weight(bitmap, thresh));
+ return thresh - bitmap_weight(bitmap, thresh);
}
/*
@@ -682,8 +682,9 @@ static bool is_ring_space_avail(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
/* try to check and get the data blocks as needed */
space = spc_bitmap_free(udev->data_bitmap, udev->dbi_thresh);
- if (space < data_needed) {
- unsigned long blocks_left = DATA_BLOCK_BITS - udev->dbi_thresh;
+ if ((space * DATA_BLOCK_SIZE) < data_needed) {
+ unsigned long blocks_left = DATA_BLOCK_BITS - udev->dbi_thresh +
+ space;
unsigned long grow;
if (blocks_left < blocks_needed) {
--
2.13.7