On Thu, Jan 16, 2020 at 04:43:41PM +0100, Jinpu Wang wrote: > On Thu, Jan 16, 2020 at 3:53 PM Leon Romanovsky <leon@xxxxxxxxxx> wrote: > > > > On Thu, Jan 16, 2020 at 01:58:56PM +0100, Jack Wang wrote: > > > From: Jack Wang <jinpu.wang@xxxxxxxxxxxxxxx> > > > > > > This is main functionality of rtrs-client module, which manages > > > set of RDMA connections for each rtrs session, does multipathing, > > > load balancing and failover of RDMA requests. > > > > > > Signed-off-by: Danil Kipnis <danil.kipnis@xxxxxxxxxxxxxxx> > > > Signed-off-by: Jack Wang <jinpu.wang@xxxxxxxxxxxxxxx> > > > --- > > > drivers/infiniband/ulp/rtrs/rtrs-clt.c | 2967 ++++++++++++++++++++++++ > > > 1 file changed, 2967 insertions(+) > > > create mode 100644 drivers/infiniband/ulp/rtrs/rtrs-clt.c > > > > > > diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c > > > new file mode 100644 > > > index 000000000000..717d19d4d930 > > > --- /dev/null > > > +++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c > > > @@ -0,0 +1,2967 @@ > > > +// SPDX-License-Identifier: GPL-2.0-or-later > > > +/* > > > + * RDMA Transport Layer > > > + * > > > + * Copyright (c) 2014 - 2018 ProfitBricks GmbH. All rights reserved. > > > + * > > > + * Copyright (c) 2018 - 2019 1&1 IONOS Cloud GmbH. All rights reserved. > > > + * > > > + * Copyright (c) 2019 - 2020 1&1 IONOS SE. All rights reserved. > > > > Please no extra lines between Copyright lines. > I checked in kernel tree, seems most of Copyright indeed contain no > extra line in between > > > > > > + */ > > > + > > > +#undef pr_fmt > > > +#define pr_fmt(fmt) KBUILD_MODNAME " L" __stringify(__LINE__) ": " fmt > > > > I never understood this pr_fmt() thing, do we really need it? > you can custorm the format for print, include modue name and line > number in this case, it's quite useful for debugging. The idea that messages are needed to be unique and don't rely on line numbers. > > > > > + > > > +#include <linux/module.h> > > > +#include <linux/rculist.h> > > > +#include <linux/blkdev.h> /* for BLK_MAX_SEGMENT_SIZE */ > > > + > > > +#include "rtrs-clt.h" > > > +#include "rtrs-log.h" > > > + > > > +#define RTRS_CONNECT_TIMEOUT_MS 30000 > > > + > > > +MODULE_DESCRIPTION("RDMA Transport Client"); > > > +MODULE_LICENSE("GPL"); > > > + > > > +static ushort nr_cons_per_session; > > > +module_param(nr_cons_per_session, ushort, 0444); > > > +MODULE_PARM_DESC(nr_cons_per_session, > > > + "Number of connections per session. (default: nr_cpu_ids)"); > > > + > > > +static int retry_cnt = 7; > > > +module_param_named(retry_cnt, retry_cnt, int, 0644); > > > +MODULE_PARM_DESC(retry_cnt, > > > + "Number of times to send the message if the remote side didn't respond with Ack or Nack (default: 7, min: " > > > + __stringify(MIN_RTR_CNT) ", max: " > > > + __stringify(MAX_RTR_CNT) ")"); > > > + > > > +static int __read_mostly noreg_cnt; > > > +module_param_named(noreg_cnt, noreg_cnt, int, 0444); > > > +MODULE_PARM_DESC(noreg_cnt, > > > + "Max number of SG entries when MR registration does not happen (default: 0)"); > > > > We don't like modules in new code. > could you elaberate a bit, no module paramters? which one? all? All of them. > > > > > > + > > > +static const struct rtrs_rdma_dev_pd_ops dev_pd_ops; > > > +static struct rtrs_rdma_dev_pd dev_pd = { > > > + .ops = &dev_pd_ops > > > +}; > > > + > > > +static struct workqueue_struct *rtrs_wq; > > > +static struct class *rtrs_clt_dev_class; > > > + > > > +static inline bool rtrs_clt_is_connected(const struct rtrs_clt *clt) > > > +{ > > > + struct rtrs_clt_sess *sess; > > > + bool connected = false; > > > + > > > + rcu_read_lock(); > > > + list_for_each_entry_rcu(sess, &clt->paths_list, s.entry) > > > + connected |= (READ_ONCE(sess->state) == RTRS_CLT_CONNECTED); > > > + rcu_read_unlock(); > > > + > > > + return connected; > > > +} > > > + > > > +static inline struct rtrs_permit * > > > +__rtrs_get_permit(struct rtrs_clt *clt, enum rtrs_clt_con_type con_type) > > > +{ > > > + size_t max_depth = clt->queue_depth; > > > + struct rtrs_permit *permit; > > > + int cpu, bit; > > > + > > > + /* Combined with cq_vector, we pin the IO to the the cpu it comes */ > > > + cpu = get_cpu(); > > > + do { > > > + bit = find_first_zero_bit(clt->permits_map, max_depth); > > > + if (unlikely(bit >= max_depth)) { > > > + put_cpu(); > > > + return NULL; > > > + } > > > + > > > + } while (unlikely(test_and_set_bit_lock(bit, clt->permits_map))); > > > + put_cpu(); > > > + > > > + permit = GET_PERMIT(clt, bit); > > > + WARN_ON(permit->mem_id != bit); > > > + permit->cpu_id = cpu; > > > + permit->con_type = con_type; > > > + > > > + return permit; > > > +} > > > + > > > +static inline void __rtrs_put_permit(struct rtrs_clt *clt, > > > + struct rtrs_permit *permit) > > > +{ > > > + clear_bit_unlock(permit->mem_id, clt->permits_map); > > > +} > > > + > > > +struct rtrs_permit *rtrs_clt_get_permit(struct rtrs_clt *clt, > > > + enum rtrs_clt_con_type con_type, > > > + int can_wait) > > > +{ > > > + struct rtrs_permit *permit; > > > + DEFINE_WAIT(wait); > > > + > > > + permit = __rtrs_get_permit(clt, con_type); > > > + if (likely(permit) || !can_wait) > > > + return permit; > > > + > > > + do { > > > + prepare_to_wait(&clt->permits_wait, &wait, > > > + TASK_UNINTERRUPTIBLE); > > > + permit = __rtrs_get_permit(clt, con_type); > > > + if (likely(permit)) > > > + break; > > > + > > > + io_schedule(); > > > + } while (1); > > > + > > > + finish_wait(&clt->permits_wait, &wait); > > > + > > > + return permit; > > > +} > > > +EXPORT_SYMBOL(rtrs_clt_get_permit); > > > + > > > +void rtrs_clt_put_permit(struct rtrs_clt *clt, struct rtrs_permit *permit) > > > +{ > > > + if (WARN_ON(!test_bit(permit->mem_id, clt->permits_map))) > > > + return; > > > + > > > + __rtrs_put_permit(clt, permit); > > > + > > > + /* > > > + * Putting a permit is a barrier, so we will observe > > > + * new entry in the wait list, no worries. > > > + */ > > > + if (waitqueue_active(&clt->permits_wait)) > > > > Where do you put permit? Does it include barrier? > __rtrs_put_permit calls clear_bit_unlock which includes barrier > rnbd-clt call rtrs_clt_put_permit before finish the request to block layer. > > > > > + wake_up(&clt->permits_wait); > > > +} > > > +EXPORT_SYMBOL(rtrs_clt_put_permit); > > > + > > > +struct rtrs_permit *rtrs_permit_from_pdu(void *pdu) > > > +{ > > > + return pdu - sizeof(struct rtrs_permit); > > > > C standard doesn't allow pointer arithmetic on void*. > gcc never complains, searched aournd: It is known bug in GCC. > https://stackoverflow.com/questions/3523145/pointer-arithmetic-for-void-pointer-in-c > > You're right, will fix. > > > > > > +} > > > +EXPORT_SYMBOL(rtrs_permit_from_pdu); > > > + > > > +void *rtrs_permit_to_pdu(struct rtrs_permit *permit) > > > +{ > > > + return permit + 1; > > > +} > > > +EXPORT_SYMBOL(rtrs_permit_to_pdu); > > > + > > > +/** > > > + * rtrs_permit_to_clt_con() - returns RDMA connection pointer by the permit > > > + * @sess: client session pointer > > > + * @permit: permit for the allocation of the RDMA buffer > > > + * Note: > > > + * IO connection starts from 1. > > > + * 0 connection is for user messages. > > > + */ > > > +static > > > +struct rtrs_clt_con *rtrs_permit_to_clt_con(struct rtrs_clt_sess *sess, > > > + struct rtrs_permit *permit) > > > +{ > > > + int id = 0; > > > + > > > + if (likely(permit->con_type == RTRS_IO_CON)) > > > + id = (permit->cpu_id % (sess->s.con_num - 1)) + 1; > > > + > > > + return to_clt_con(sess->s.con[id]); > > > +} > > > + > > > +static bool __rtrs_clt_change_state(struct rtrs_clt_sess *sess, > > > + enum rtrs_clt_state new_state) > > > +{ > > > + enum rtrs_clt_state old_state; > > > + bool changed = false; > > > + > > > + lockdep_assert_held(&sess->state_wq.lock); > > > + > > > + old_state = sess->state; > > > + switch (new_state) { > > > + case RTRS_CLT_CONNECTING: > > > + switch (old_state) { > > > > Double switch is better to be avoided. > what's the better way to do it? Rewrite function to be more readable. > > > > > + case RTRS_CLT_RECONNECTING: > > > + changed = true; > > > + /* FALLTHRU */ > > > + default: > > > + break; > > > + } > > > + break; > > > > > > .... > > > > Thanks > Thanks