diff mbox series

[v4,1/2] drivers: base: cacheinfo: Do not populate sysfs for unknown cache types

Message ID 1538666406-7504-2-git-send-email-jhugo@codeaurora.org (mailing list archive)
State Accepted, archived
Delegated to: Rafael Wysocki
Headers show
Series PPTT handle Handle architecturally unknown cache types | expand

Commit Message

Jeffrey Hugo Oct. 4, 2018, 3:20 p.m. UTC 
If a cache has an unknown type because neither the hardware nor the
firmware told us, an entry in the sysfs tree will be made, but the type
file will not be present.  lscpu depends on the type file being present
for every entry, and will error out without printing system information
if lscpu cannot open the type file.

Presenting information about a cache without indicating its type is not
useful, therefore if we hit a cache with an unknown type, stop populating
sysfs so that userspace has the maximum amount of useful information.

This addresses the following lscpu error, which prevents any output.
lscpu: cannot open /sys/devices/system/cpu/cpu0/cache/index3/type: No such
file or directory

Suggested-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
---
 drivers/base/cacheinfo.c | 2 ++
 1 file changed, 2 insertions(+)

Comments

Greg KH Oct. 4, 2018, 3:41 p.m. UTC | #1 
On Thu, Oct 04, 2018 at 09:20:05AM -0600, Jeffrey Hugo wrote:
> If a cache has an unknown type because neither the hardware nor the
> firmware told us, an entry in the sysfs tree will be made, but the type
> file will not be present.  lscpu depends on the type file being present
> for every entry, and will error out without printing system information
> if lscpu cannot open the type file.
> 
> Presenting information about a cache without indicating its type is not
> useful, therefore if we hit a cache with an unknown type, stop populating
> sysfs so that userspace has the maximum amount of useful information.
> 
> This addresses the following lscpu error, which prevents any output.
> lscpu: cannot open /sys/devices/system/cpu/cpu0/cache/index3/type: No such
> file or directory
> 
> Suggested-by: Sudeep Holla <sudeep.holla@arm.com>
> Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
> Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>
> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
> ---
>  drivers/base/cacheinfo.c | 2 ++
>  1 file changed, 2 insertions(+)

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff mbox series

Patch

diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index 5d5b598..cf78fa6 100644
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -615,6 +615,8 @@  static int cache_add_dev(unsigned int cpu)
 		this_leaf = this_cpu_ci->info_list + i;
 		if (this_leaf->disable_sysfs)
 			continue;
+		if (this_leaf->type == CACHE_TYPE_NOCACHE)
+			break;
 		cache_groups = cache_get_attribute_groups(this_leaf);
 		ci_dev = cpu_device_create(parent, this_leaf, cache_groups,
 					   "index%1u", i);