Re: [PATCH] scsi: ufs: mcq: Limit the amount of inflight requests
From: Bart Van Assche
Date: Thu Mar 30 2023 - 12:39:33 EST
On 3/30/23 06:11, Avri Altman wrote:
diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 35a3bd95c5e4..d529c42a682a 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -8468,6 +8468,10 @@ static int ufshcd_alloc_mcq(struct ufs_hba *hba)
if (ret)
goto err;
+ if (WARN_ONCE(hba->nutrs * hba->nr_hw_queues > (1 << 16) - 1,
+ "there can be at most 1<<16 inflight requests\n"))
+ goto err;
+
/*
* Previously allocated memory for nutrs may not be enough in MCQ mode.
* Number of supported tags in MCQ mode may be larger than SDB mode.
Hi Avri,
WARN*() should only be used to report kernel bugs. hba->nutrs *
hba->nr_hw_queues being too large is not a kernel bug but a
configuration issue.
Instead of failing MCQ allocation, shouldn't
ufshcd_mcq_decide_queue_depth() be modified such that it restricts
hba->nutrs to a value that can be supported?
Thanks,
Bart.