On 04/14/15 16:06, Ananyev, Konstantin wrote: > >> -----Original Message----- >> From: Vlad Zolotarov [mailto:vladz at cloudius-systems.com] >> Sent: Tuesday, April 14, 2015 1:49 PM >> To: Thomas Monjalon; Ananyev, Konstantin; Zhang, Helin >> Cc: dev at dpdk.org >> Subject: Re: [PATCH] ixgbe: fix build with gcc 4.4 >> >> >> >> On 04/14/15 12:31, Thomas Monjalon wrote: >>> With GCC 4.4.7 from CentOS 6.5, the following errors arise: >>> >>> lib/librte_pmd_ixgbe/ixgbe_rxtx.c: In function ?ixgbe_dev_rx_queue_setup?: >>> lib/librte_pmd_ixgbe/ixgbe_rxtx.c:2509: error: missing initializer >>> lib/librte_pmd_ixgbe/ixgbe_rxtx.c:2509: error: (near initialization for >>> ?dev_info.driver_name?) >>> >>> lib/librte_pmd_ixgbe/ixgbe_rxtx.c: In function ?ixgbe_set_rsc?: >>> lib/librte_pmd_ixgbe/ixgbe_rxtx.c:4072: error: missing initializer >>> lib/librte_pmd_ixgbe/ixgbe_rxtx.c:4072: error: (near initialization for >>> ?dev_info.driver_name?) >>> >>> lib/librte_pmd_ixgbe/ixgbe_rxtx.c: In function >>> ?ixgbe_recv_pkts_lro_single_alloc?: >>> lib/librte_pmd_ixgbe/ixgbe_rxtx.c:1479: error: ?next_rsc_entry? may be used >>> uninitialized in this function >>> lib/librte_pmd_ixgbe/ixgbe_rxtx.c:1480: error: ?next_rxe? may be used >>> uninitialized in this function >>> >>> Fixes: 8eecb3295aed ("ixgbe: add LRO support") >>> >>> Signed-off-by: Thomas Monjalon <thomas.monjalon at 6wind.com> >>> --- >>> lib/librte_pmd_ixgbe/ixgbe_rxtx.c | 8 ++++---- >>> 1 file changed, 4 insertions(+), 4 deletions(-) >>> >>> diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c >>> b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c >>> index f1da9ec..a2b8631 100644 >>> --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c >>> +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c >>> @@ -1476,8 +1476,8 @@ ixgbe_recv_pkts_lro(void *rx_queue, struct rte_mbuf >>> **rx_pkts, uint16_t nb_pkts, >>> bool eop; >>> struct ixgbe_rx_entry *rxe; >>> struct ixgbe_rsc_entry *rsc_entry; >>> - struct ixgbe_rsc_entry *next_rsc_entry; >>> - struct ixgbe_rx_entry *next_rxe; >>> + struct ixgbe_rsc_entry *next_rsc_entry = NULL; >>> + struct ixgbe_rx_entry *next_rxe = NULL; >>> struct rte_mbuf *first_seg; >>> struct rte_mbuf *rxm; >>> struct rte_mbuf *nmb; >>> @@ -2506,7 +2506,7 @@ ixgbe_dev_rx_queue_setup(struct rte_eth_dev *dev, >>> struct ixgbe_rx_queue *rxq; >>> struct ixgbe_hw *hw; >>> uint16_t len; >>> - struct rte_eth_dev_info dev_info = { 0 }; >>> + struct rte_eth_dev_info dev_info = { .max_rx_queues = 0 }; >>> struct rte_eth_rxmode *dev_rx_mode = &dev->data->dev_conf.rxmode; >>> bool rsc_requested = false; >>> >>> @@ -4069,7 +4069,7 @@ ixgbe_set_rsc(struct rte_eth_dev *dev) >>> { >>> struct rte_eth_rxmode *rx_conf = &dev->data->dev_conf.rxmode; >>> struct ixgbe_hw *hw = IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private); >>> - struct rte_eth_dev_info dev_info = { 0 }; >>> + struct rte_eth_dev_info dev_info = { .max_rx_queues = 0 }; >> Hmmm... Unless I miss something this and one above would zero only a >> single field - "max_rx_queues"; and would leave the rest uninitialized. >> The original code intend to zero the whole struct. The alternative to >> the original lines could be usage of memset(). > As I understand, in that case compiler had to set all non-explicitly > initialised members to 0. > So I think we are ok here.
Yeah, I guess it does zero-initializes the rest (https://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html) however I don't understand how the above change fixes the error if it complains about the dev_info.driver_name? What I'm trying to say - the proposed fix is completely unclear and confusing. Think of somebody reading this line in a month from today - he wouldn't get a clue why is it there, why to explicitly set max_rx_queues to zero and leave the rest be zeroed automatically... Why to add such artifacts to the code instead of just zeroing the struct with a memset() and putting a good clear comment above it explaining why we use a memset() and not and initializer? > >>> bool rsc_capable = false; >>> uint16_t i; >>> uint32_t rdrxctl;
