linux-kernel - [PATCH] padata: use alignment when calculating the number of worker threads

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Date:   Wed, 22 Feb 2023 16:33:12 -0800
From:   Anthony Yznaga <anthony.yznaga@...cle.com>
To:     daniel.m.jordan@...cle.com, steffen.klassert@...unet.com
Cc:     linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] padata: use alignment when calculating the number of worker threads

For multithreaded jobs the computed chunk size is rounded up by the
caller-specified alignment. However, the number of worker threads to
use is computed using the minimum chunk size without taking alignment
into account. A sufficiently large alignment value can result in too
many worker threads being allocated for the job.

Signed-off-by: Anthony Yznaga <anthony.yznaga@...cle.com>
---
 kernel/padata.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/padata.c b/kernel/padata.c
index e007b8a4b738..4abc536ecdb1 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -491,7 +491,7 @@ void __init padata_do_multithreaded(struct padata_mt_job *job)
 		return;
 
 	/* Ensure at least one thread when size < min_chunk. */
-	nworks = max(job->size / job->min_chunk, 1ul);
+	nworks = max(job->size / max(job->min_chunk, job->align), 1ul);
 	nworks = min(nworks, job->max_threads);
 
 	if (nworks == 1) {
-- 
1.8.3.1