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author | Julian Wiedmann <jwi@linux.ibm.com> | 2019-04-01 10:08:08 +0200 |
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committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2019-05-08 15:01:23 +0200 |
commit | 3060781f2664d34af641247aeac62696405a3fde (patch) | |
tree | 6dc9b7de3d10a5226862c867801b2aa58059a62f /Documentation/DMA-API-HOWTO.txt | |
parent | 22e2fe8551f83d43619211623c739e98dfa8ff08 (diff) | |
download | linux-3060781f2664d34af641247aeac62696405a3fde.tar.bz2 |
s390/qdio: allow to scan all Output SBALs in one go
Old code restricted the number of inspected SBALs to
QDIO_MAX_BUFFERS_PER_Q - 1, as otherwise the first_to_check and
first_to_kick cursors could overlap. Subsequent code would then assume that
there was no progress on the queue, when in fact _all_ SBALs on the queue
were ready-to-process.
This limitation no longer applies, so allow the queue-scan code to inspect
all SBALs on the queue. Note that qeth requires an additional patch
("s390/qeth: stop/wake TX queues based on their fill level"), to avoid
potential queue stalls when all 128 SBALs are reported as ready-to-process.
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'Documentation/DMA-API-HOWTO.txt')
0 files changed, 0 insertions, 0 deletions