5.15-stable review patch. If anyone has any objections, please let me know.
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From: Joy Chakraborty joychakr@google.com
commit 28b008751aa295612318a0fbb2f22dd4f6a83139 upstream.
reg_read() callback registered with nvmem core expects 0 on success and a negative value on error but rmem_read() returns the number of bytes read which is treated as an error at the nvmem core.
This does not break when rmem is accessed using sysfs via bin_attr_nvmem_read()/write() but causes an error when accessed from places like nvmem_access_with_keepouts(), etc.
Change to return 0 on success and error in case memory_read_from_buffer() returns an error or -EIO if bytes read do not match what was requested.
Fixes: 5a3fa75a4d9c ("nvmem: Add driver to expose reserved memory as nvmem") Cc: stable@vger.kernel.org Signed-off-by: Joy Chakraborty joychakr@google.com Reviewed-by: Dan Carpenter dan.carpenter@linaro.org Signed-off-by: Srinivas Kandagatla srinivas.kandagatla@linaro.org Link: https://lore.kernel.org/r/20240628113704.13742-2-srinivas.kandagatla@linaro.... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/nvmem/rmem.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/drivers/nvmem/rmem.c +++ b/drivers/nvmem/rmem.c @@ -46,7 +46,10 @@ static int rmem_read(void *context, unsi
memunmap(addr);
- return count; + if (count < 0) + return count; + + return count == bytes ? 0 : -EIO; }
static int rmem_probe(struct platform_device *pdev)