linux-kernel - [PATCH v4 3/4] arch_topology: Remove early cacheinfo error message if -ENOENT

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Date:   Fri, 14 Apr 2023 10:14:51 +0200
From:   Pierre Gondois <pierre.gondois@....com>
To:     linux-kernel@...r.kernel.org
Cc:     Radu Rendec <rrendec@...hat.com>,
        Alexandre Ghiti <alexghiti@...osinc.com>,
        Conor Dooley <conor.dooley@...rochip.com>,
        Will Deacon <will@...nel.org>,
        Florian Fainelli <f.fainelli@...il.com>,
        Pierre Gondois <pierre.gondois@....com>,
        Sudeep Holla <sudeep.holla@....com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Palmer Dabbelt <palmer@...osinc.com>,
        Gavin Shan <gshan@...hat.com>
Subject: [PATCH v4 3/4] arch_topology: Remove early cacheinfo error message if -ENOENT

fetch_cache_info() tries to get the number of cache leaves/levels
for each CPU in order to pre-allocate memory for cacheinfo struct.
Allocating this memory later triggers a:
  'BUG: sleeping function called from invalid context'
in PREEMPT_RT kernels.

If there is no cache related information available in DT or ACPI,
fetch_cache_info() fails and an error message is printed:
  'Early cacheinfo failed, ret = ...'

Not having cache information should be a valid configuration.
Remove the error message if fetch_cache_info() fails with -ENOENT.

Suggested-by: Conor Dooley <conor.dooley@...rochip.com>
Link: https://lore.kernel.org/all/20230404-hatred-swimmer-6fecdf33b57a@spud/
Signed-off-by: Pierre Gondois <pierre.gondois@....com>
Reviewed-by: Conor Dooley <conor.dooley@...rochip.com>
---
 drivers/base/arch_topology.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index b1c1dd38ab01..c4b6198d7461 100644
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -843,10 +843,11 @@ void __init init_cpu_topology(void)
 
 	for_each_possible_cpu(cpu) {
 		ret = fetch_cache_info(cpu);
-		if (ret) {
+		if (!ret)
+			continue;
+		else if (ret != -ENOENT)
 			pr_err("Early cacheinfo failed, ret = %d\n", ret);
-			break;
-		}
+		return;
 	}
 }
 
-- 
2.25.1