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|
// SPDX-License-Identifier: GPL-2.0-only
/*
* fs/nfs/nfs4session.c
*
* Copyright (c) 2012 Trond Myklebust <Trond.Myklebust@netapp.com>
*
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/sunrpc/sched.h>
#include <linux/sunrpc/bc_xprt.h>
#include <linux/nfs.h>
#include <linux/nfs4.h>
#include <linux/nfs_fs.h>
#include <linux/module.h>
#include "nfs4_fs.h"
#include "internal.h"
#include "nfs4session.h"
#include "callback.h"
#define NFSDBG_FACILITY NFSDBG_STATE
static void nfs4_init_slot_table(struct nfs4_slot_table *tbl, const char *queue)
{
tbl->highest_used_slotid = NFS4_NO_SLOT;
spin_lock_init(&tbl->slot_tbl_lock);
rpc_init_priority_wait_queue(&tbl->slot_tbl_waitq, queue);
init_waitqueue_head(&tbl->slot_waitq);
init_completion(&tbl->complete);
}
/*
* nfs4_shrink_slot_table - free retired slots from the slot table
*/
static void nfs4_shrink_slot_table(struct nfs4_slot_table *tbl, u32 newsize)
{
struct nfs4_slot **p;
if (newsize >= tbl->max_slots)
return;
p = &tbl->slots;
while (newsize--)
p = &(*p)->next;
while (*p) {
struct nfs4_slot *slot = *p;
*p = slot->next;
kfree(slot);
tbl->max_slots--;
}
}
/**
* nfs4_slot_tbl_drain_complete - wake waiters when drain is complete
* @tbl: controlling slot table
*
*/
void nfs4_slot_tbl_drain_complete(struct nfs4_slot_table *tbl)
{
if (nfs4_slot_tbl_draining(tbl))
complete(&tbl->complete);
}
/*
* nfs4_free_slot - free a slot and efficiently update slot table.
*
* freeing a slot is trivially done by clearing its respective bit
* in the bitmap.
* If the freed slotid equals highest_used_slotid we want to update it
* so that the server would be able to size down the slot table if needed,
* otherwise we know that the highest_used_slotid is still in use.
* When updating highest_used_slotid there may be "holes" in the bitmap
* so we need to scan down from highest_used_slotid to 0 looking for the now
* highest slotid in use.
* If none found, highest_used_slotid is set to NFS4_NO_SLOT.
*
* Must be called while holding tbl->slot_tbl_lock
*/
void nfs4_free_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
{
u32 slotid = slot->slot_nr;
/* clear used bit in bitmap */
__clear_bit(slotid, tbl->used_slots);
/* update highest_used_slotid when it is freed */
if (slotid == tbl->highest_used_slotid) {
u32 new_max = find_last_bit(tbl->used_slots, slotid);
if (new_max < slotid)
tbl->highest_used_slotid = new_max;
else {
tbl->highest_used_slotid = NFS4_NO_SLOT;
nfs4_slot_tbl_drain_complete(tbl);
}
}
dprintk("%s: slotid %u highest_used_slotid %u\n", __func__,
slotid, tbl->highest_used_slotid);
}
static struct nfs4_slot *nfs4_new_slot(struct nfs4_slot_table *tbl,
u32 slotid, u32 seq_init, gfp_t gfp_mask)
{
struct nfs4_slot *slot;
slot = kzalloc(sizeof(*slot), gfp_mask);
if (slot) {
slot->table = tbl;
slot->slot_nr = slotid;
slot->seq_nr = seq_init;
slot->seq_nr_highest_sent = seq_init;
slot->seq_nr_last_acked = seq_init - 1;
}
return slot;
}
static struct nfs4_slot *nfs4_find_or_create_slot(struct nfs4_slot_table *tbl,
u32 slotid, u32 seq_init, gfp_t gfp_mask)
{
struct nfs4_slot **p, *slot;
p = &tbl->slots;
for (;;) {
if (*p == NULL) {
*p = nfs4_new_slot(tbl, tbl->max_slots,
seq_init, gfp_mask);
if (*p == NULL)
break;
tbl->max_slots++;
}
slot = *p;
if (slot->slot_nr == slotid)
return slot;
p = &slot->next;
}
return ERR_PTR(-ENOMEM);
}
static void nfs4_lock_slot(struct nfs4_slot_table *tbl,
struct nfs4_slot *slot)
{
u32 slotid = slot->slot_nr;
__set_bit(slotid, tbl->used_slots);
if (slotid > tbl->highest_used_slotid ||
tbl->highest_used_slotid == NFS4_NO_SLOT)
tbl->highest_used_slotid = slotid;
slot->generation = tbl->generation;
}
/*
* nfs4_try_to_lock_slot - Given a slot try to allocate it
*
* Note: must be called with the slot_tbl_lock held.
*/
bool nfs4_try_to_lock_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
{
if (nfs4_test_locked_slot(tbl, slot->slot_nr))
return false;
nfs4_lock_slot(tbl, slot);
return true;
}
/*
* nfs4_lookup_slot - Find a slot but don't allocate it
*
* Note: must be called with the slot_tbl_lock held.
*/
struct nfs4_slot *nfs4_lookup_slot(struct nfs4_slot_table *tbl, u32 slotid)
{
if (slotid <= tbl->max_slotid)
return nfs4_find_or_create_slot(tbl, slotid, 0, GFP_NOWAIT);
return ERR_PTR(-E2BIG);
}
static int nfs4_slot_get_seqid(struct nfs4_slot_table *tbl, u32 slotid,
u32 *seq_nr)
__must_hold(&tbl->slot_tbl_lock)
{
struct nfs4_slot *slot;
int ret;
slot = nfs4_lookup_slot(tbl, slotid);
ret = PTR_ERR_OR_ZERO(slot);
if (!ret)
*seq_nr = slot->seq_nr;
return ret;
}
/*
* nfs4_slot_seqid_in_use - test if a slot sequence id is still in use
*
* Given a slot table, slot id and sequence number, determine if the
* RPC call in question is still in flight. This function is mainly
* intended for use by the callback channel.
*/
static bool nfs4_slot_seqid_in_use(struct nfs4_slot_table *tbl,
u32 slotid, u32 seq_nr)
{
u32 cur_seq = 0;
bool ret = false;
spin_lock(&tbl->slot_tbl_lock);
if (nfs4_slot_get_seqid(tbl, slotid, &cur_seq) == 0 &&
cur_seq == seq_nr && test_bit(slotid, tbl->used_slots))
ret = true;
spin_unlock(&tbl->slot_tbl_lock);
return ret;
}
/*
* nfs4_slot_wait_on_seqid - wait until a slot sequence id is complete
*
* Given a slot table, slot id and sequence number, wait until the
* corresponding RPC call completes. This function is mainly
* intended for use by the callback channel.
*/
int nfs4_slot_wait_on_seqid(struct nfs4_slot_table *tbl,
u32 slotid, u32 seq_nr,
unsigned long timeout)
{
if (wait_event_timeout(tbl->slot_waitq,
!nfs4_slot_seqid_in_use(tbl, slotid, seq_nr),
timeout) == 0)
return -ETIMEDOUT;
return 0;
}
/*
* nfs4_alloc_slot - efficiently look for a free slot
*
* nfs4_alloc_slot looks for an unset bit in the used_slots bitmap.
* If found, we mark the slot as used, update the highest_used_slotid,
* and respectively set up the sequence operation args.
*
* Note: must be called with under the slot_tbl_lock.
*/
struct nfs4_slot
|