nvmem: properly handle returned value nvmem_reg_read

BugLink: http://bugs.launchpad.net/bugs/1815234
[ Upstream commit 50808bfcc14b854775a9f1d0abe3dac2babcf5c3 ]

Function nvmem_reg_read can return a non zero value indicating an error.
This returned value must be read and error propagated to
nvmem_cell_prepare_write_buffer. Silence the following gcc warning (W=1):

drivers/nvmem/core.c:1093:9: warning: variable 'rc' set but
 not used [-Wunused-but-set-variable]

Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 5a5cefd12153af7fe8ec3ae114e41a2cb17383a3..66fa83bd476388f621996d6f88e1590475a19cdf 100644 (file)
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -1050,6 +1050,8 @@ static void *nvmem_cell_prepare_write_buffer(struct nvmem_cell *cell,
 
                /* setup the first byte with lsb bits from nvmem */
                rc = nvmem_reg_read(nvmem, cell->offset, &v, 1);
+               if (rc)
+                       goto err;
                *b++ |= GENMASK(bit_offset - 1, 0) & v;
 
                /* setup rest of the byte if any */
@@ -1068,11 +1070,16 @@ static void *nvmem_cell_prepare_write_buffer(struct nvmem_cell *cell,
                /* setup the last byte with msb bits from nvmem */
                rc = nvmem_reg_read(nvmem,
                                    cell->offset + cell->bytes - 1, &v, 1);
+               if (rc)
+                       goto err;
                *p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;
 
        }
 
        return buf;
+err:
+       kfree(buf);
+       return ERR_PTR(rc);
 }
 
 /**