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 --- drivers/nvmem/rmem.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/nvmem/rmem.c b/drivers/nvmem/rmem.c index 752d0bf4445e..7f907c5a445e 100644 --- a/drivers/nvmem/rmem.c +++ b/drivers/nvmem/rmem.c @@ -46,7 +46,10 @@ static int rmem_read(void *context, unsigned int offset,

memunmap(addr);

- return count; + if (count < 0) + return count; + + return count == bytes ? 0 : -EIO; }

static int rmem_probe(struct platform_device *pdev)