From: Jacob Keller jacob.e.keller@intel.com
[ Upstream commit d5b90e99e1d51b7b5d2b74fbc4c2db236a510913 ]
commit fdd41ec21e15 ("devlink: Return right error code in case of errors for region read") modified the region read code to report errors properly in unexpected cases.
In the case where the start_offset and ret_offset match, it unilaterally converted this into an error. This causes an issue for the "dump" version of the command. In this case, the devlink region dump will always report an invalid argument:
000000000000ffd0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff 000000000000ffe0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff devlink answers: Invalid argument 000000000000fff0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
This occurs because the expected flow for the dump is to return 0 after there is no further data.
The simplest fix would be to stop converting the error code to -EINVAL if start_offset == ret_offset. However, avoid unnecessary work by checking for when start_offset is larger than the region size and returning 0 upfront.
Fixes: fdd41ec21e15 ("devlink: Return right error code in case of errors for region read") Signed-off-by: Jacob Keller jacob.e.keller@intel.com Acked-by: Jiri Pirko jiri@mellanox.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/core/devlink.c | 6 ++++++ 1 file changed, 6 insertions(+)
--- a/net/core/devlink.c +++ b/net/core/devlink.c @@ -3986,6 +3986,12 @@ static int devlink_nl_cmd_region_read_du goto out_unlock; }
+ /* return 0 if there is no further data to read */ + if (start_offset >= region->size) { + err = 0; + goto out_unlock; + } + hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, &devlink_nl_family, NLM_F_ACK | NLM_F_MULTI, DEVLINK_CMD_REGION_READ);