tcmu: fix free block calculation

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>
This commit is contained in:
Mike Christie 2017-11-28 12:40:35 -06:00 committed by Nicholas Bellinger
parent 1a1fc0b88e
commit 3c0f26ff9d

View file

@ -637,7 +637,7 @@ 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) 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);
} }
/* /*
@ -677,8 +677,9 @@ static bool is_ring_space_avail(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
/* try to check and get the data blocks as needed */ /* try to check and get the data blocks as needed */
space = spc_bitmap_free(udev->data_bitmap, udev->dbi_thresh); space = spc_bitmap_free(udev->data_bitmap, udev->dbi_thresh);
if (space < data_needed) { if ((space * DATA_BLOCK_SIZE) < data_needed) {
unsigned long blocks_left = DATA_BLOCK_BITS - udev->dbi_thresh; unsigned long blocks_left = DATA_BLOCK_BITS - udev->dbi_thresh +
space;
unsigned long grow; unsigned long grow;
if (blocks_left < blocks_needed) { if (blocks_left < blocks_needed) {