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 <[email protected]> --- 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 76f0e5a..b7eeb25 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -636,7 +636,7 @@ 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); } /* @@ -676,8 +676,9 @@ 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) { -- 1.8.3.1
