On 6/4/19 7:23 AM, Vinod Koul wrote: > [CAUTION: External Email] > > On 31-05-19, 19:43, Hook, Gary wrote: >> The dmatest module parameter 'timeout' is documented as accepting a >> -1 to mean "infinite timeout". Change the parameter to to signed >> integer, and check the value to call the appropriate wait_event() >> function. >> >> Signed-off-by: Gary R Hook <gary.h...@amd.com> >> --- >> drivers/dma/dmatest.c | 11 ++++++++--- >> 1 file changed, 8 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/dma/dmatest.c b/drivers/dma/dmatest.c >> index b96814a7dceb..28a237686578 100644 >> --- a/drivers/dma/dmatest.c >> +++ b/drivers/dma/dmatest.c >> @@ -63,7 +63,7 @@ MODULE_PARM_DESC(pq_sources, >> "Number of p+q source buffers (default: 3)"); >> >> static int timeout = 3000; >> -module_param(timeout, uint, S_IRUGO | S_IWUSR); >> +module_param(timeout, int, S_IRUGO | S_IWUSR); >> MODULE_PARM_DESC(timeout, "Transfer Timeout in msec (default: 3000), " >> "Pass -1 for infinite timeout"); >> >> @@ -795,8 +795,13 @@ static int dmatest_func(void *data) >> } >> dma_async_issue_pending(chan); >> >> - wait_event_freezable_timeout(thread->done_wait, done->done, >> - >> msecs_to_jiffies(params->timeout)); >> + /* A timeout value of -1 means infinite wait */ >> + if (timeout == -1) >> + wait_event_freezable(thread->done_wait, done->done); > > well i am not too happy that we have a infinite wait and no way to > cancel, maybe remove this case?
Well, I was uncomfortable with documentation that didn't match behavior. I see two choices (and I just chose one to start a conversation): 1) Accept this patch, with an infinite timeout, or 2) Leave the data type alone, but change the description to state that timeout values up to hex 0xFFFFFFFF / decimal 4294967295 can be used, emulating an "infinite" wait. A very long wait that eventually pops a timer is probably preferable. I don't think there are any conversion issues since the jiffy parameter to wait_event_freezable_timeout() is converted to a long. I could be wrong about that. I'm happy to go with option (2). Please suggest a course of action. grh > >> + else >> + wait_event_freezable_timeout(thread->done_wait, >> + done->done, >> + msecs_to_jiffies(params->timeout)); >> >> status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
