linux-kernel - [PATCH] nvmem: core: return -ENOENT if nvmem cell is not found

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Date:   Thu,  5 Jan 2023 14:59:31 +0100
From:   Michael Walle <michael@...le.cc>
To:     Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        Alexander Stein <alexander.stein@...tq-group.com>
Cc:     Michael Walle <michael@...le.cc>, linux-kernel@...r.kernel.org,
        Miquel Raynal <miquel.raynal@...tlin.com>
Subject: [PATCH] nvmem: core: return -ENOENT if nvmem cell is not found

Prior to commit 3cb05fdbaed6 ("nvmem: core: add an index parameter to
the cell") of_nvmem_cell_get() would return -ENOENT if the cell wasn't
found. Particularly, if of_property_match_string() returned -EINVAL,
that return code was passed as the index to of_parse_phandle(), which
then detected it as invalid and returned NULL. That led to an return
code of -ENOENT.

With the new code, the negative index will lead to an -EINVAL of
of_parse_phandle_with_optional_args() which pass straight to the
caller and break those who expect an -ENOENT.

Fix it by always returning -ENOENT.

Fixes: 3cb05fdbaed6 ("nvmem: core: add an index parameter to the cell")
Reported-by: Alexander Stein <alexander.stein@...tq-group.com>
Signed-off-by: Michael Walle <michael@...le.cc>
---

Alexander, could you give this another try? I've changed it slightly,
so it's a better match with how the handling was before.

 drivers/nvmem/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 1b61c8bf0de4..cc885b602690 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -1343,7 +1343,7 @@ struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *id)
 						  "#nvmem-cell-cells",
 						  index, &cell_spec);
 	if (ret)
-		return ERR_PTR(ret);
+		return ERR_PTR(-ENOENT);

 	if (cell_spec.args_count > 1)
 		return ERR_PTR(-EINVAL);
-- 
2.30.2