06/11/2024 13:19, Morten Brørup: > > From: Bruce Richardson [mailto:bruce.richard...@intel.com] > > Sent: Wednesday, 6 November 2024 12.52 > > > > On Fri, Oct 25, 2024 at 11:52:23AM +0000, Morten Brørup wrote: > > > When configuring DPDK for one queue per port > > > (#define RTE_MAX_QUEUES_PER_PORT 1), compilation of some network > > drivers > > > fails with e.g.: > > > > > > ../drivers/net/bnxt/bnxt_rxq.c: In function 'bnxt_rx_queue_stop': > > > ../drivers/net/bnxt/bnxt_rxq.c:587:34: error: array subscript 1 is > > above array bounds of 'uint8_t[1]' {aka 'unsigned char[1]'} [- > > Werror=array-bounds=] > > > 587 | dev->data->rx_queue_state[q_id] = > > RTE_ETH_QUEUE_STATE_STOPPED; > > > | ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~ > > > In file included from ../drivers/net/bnxt/bnxt.h:16, > > > from ../drivers/net/bnxt/bnxt_rxq.c:10: > > > ../lib/ethdev/ethdev_driver.h:168:17: note: while referencing > > 'rx_queue_state' > > > 168 | uint8_t rx_queue_state[RTE_MAX_QUEUES_PER_PORT]; > > > | ^~~~~~~~~~~~~~ > > > > > > To fix this, a hint is added to the network drivers where a compiler > > in > > > the CI has been seen to emit the above error when DPDK is configured > > for > > > one queue per port, but we know that the error cannot occur. [...] > > > for (i = 0; i < dev->data->nb_rx_queues; i++) { > > > + __rte_assume(i < RTE_MAX_QUEUES_PER_PORT); > > > rxq = dev->data->rx_queues[i]; [...] > > BTW: is this the only/best way to put in the assumption? If it were me, > > I'd > > look to put before the loop the underlying assumption that > > (dev->data->nb_XX_queues < RTE_MAX_QUEUES_PER_PORT), rather than > > putting > > the assumption on "i". > > I would also prefer putting it outside the loop, > but it doesn't work in cases where the variable > is potentially modified inside the loop. > And here's the problem with that: > Passing it as a parameter to a logging macro > makes the compiler think it is "potentially modified".
I don't understand this part. "i" is not a pointer, so how it can be modified? > And thus, I have to put it where it hurts, and decided to do it consistently. Why doing something heavier consistently? I would prefer to catch the problematic cases only with this macro.
