FreeBSD/Linux Kernel Cross Reference
sys/ofed/drivers/infiniband/core/ib_fmr_pool.c

     /*-
      * SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0
      *
      * Copyright (c) 2004 Topspin Communications.  All rights reserved.
      * Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
      *
      * This software is available to you under a choice of one of two
      * licenses.  You may choose to be licensed under the terms of the GNU
      * General Public License (GPL) Version 2, available from the file
     * COPYING in the main directory of this source tree, or the
     * OpenIB.org BSD license below:
     *
     *     Redistribution and use in source and binary forms, with or
     *     without modification, are permitted provided that the following
     *     conditions are met:
     *
     *      - Redistributions of source code must retain the above
     *        copyright notice, this list of conditions and the following
     *        disclaimer.
     *
     *      - Redistributions in binary form must reproduce the above
     *        copyright notice, this list of conditions and the following
     *        disclaimer in the documentation and/or other materials
     *        provided with the distribution.
     *
     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
     * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
     * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
     * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
     * SOFTWARE.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include <linux/errno.h>
    #include <linux/spinlock.h>
    #include <linux/slab.h>
    #include <linux/jhash.h>
    #include <linux/kthread.h>
    #include <linux/wait.h>
    
    #include <rdma/ib_fmr_pool.h>
    
    #include "core_priv.h"
    
    #define PFX "fmr_pool: "
    
    enum {
            IB_FMR_MAX_REMAPS = 32,
    
            IB_FMR_HASH_BITS  = 8,
            IB_FMR_HASH_SIZE  = 1 << IB_FMR_HASH_BITS,
            IB_FMR_HASH_MASK  = IB_FMR_HASH_SIZE - 1
    };
    
    /*
     * If an FMR is not in use, then the list member will point to either
     * its pool's free_list (if the FMR can be mapped again; that is,
     * remap_count < pool->max_remaps) or its pool's dirty_list (if the
     * FMR needs to be unmapped before being remapped).  In either of
     * these cases it is a bug if the ref_count is not 0.  In other words,
     * if ref_count is > 0, then the list member must not be linked into
     * either free_list or dirty_list.
     *
     * The cache_node member is used to link the FMR into a cache bucket
     * (if caching is enabled).  This is independent of the reference
     * count of the FMR.  When a valid FMR is released, its ref_count is
     * decremented, and if ref_count reaches 0, the FMR is placed in
     * either free_list or dirty_list as appropriate.  However, it is not
     * removed from the cache and may be "revived" if a call to
     * ib_fmr_register_physical() occurs before the FMR is remapped.  In
     * this case we just increment the ref_count and remove the FMR from
     * free_list/dirty_list.
     *
     * Before we remap an FMR from free_list, we remove it from the cache
     * (to prevent another user from obtaining a stale FMR).  When an FMR
     * is released, we add it to the tail of the free list, so that our
     * cache eviction policy is "least recently used."
     *
     * All manipulation of ref_count, list and cache_node is protected by
     * pool_lock to maintain consistency.
     */
    
    struct ib_fmr_pool {
            spinlock_t                pool_lock;
    
            int                       pool_size;
            int                       max_pages;
            int                       max_remaps;
            int                       dirty_watermark;
            int                       dirty_len;
            struct list_head          free_list;
            struct list_head          dirty_list;
            struct hlist_head        *cache_bucket;
    
           void                     (*flush_function)(struct ib_fmr_pool *pool,
                                                      void *              arg);
           void                     *flush_arg;
   
           struct task_struct       *thread;
   
           atomic_t                  req_ser;
           atomic_t                  flush_ser;
   
           wait_queue_head_t         force_wait;
   };
   
   static inline u32 ib_fmr_hash(u64 first_page)
   {
           return jhash_2words((u32) first_page, (u32) (first_page >> 32), 0) &
                   (IB_FMR_HASH_SIZE - 1);
   }
   
   /* Caller must hold pool_lock */
   static inline struct ib_pool_fmr *ib_fmr_cache_lookup(struct ib_fmr_pool *pool,
                                                         u64 *page_list,
                                                         int  page_list_len,
                                                         u64  io_virtual_address)
   {
           struct hlist_head *bucket;
           struct ib_pool_fmr *fmr;
   
           if (!pool->cache_bucket)
                   return NULL;
   
           bucket = pool->cache_bucket + ib_fmr_hash(*page_list);
   
           hlist_for_each_entry(fmr, bucket, cache_node)
                   if (io_virtual_address == fmr->io_virtual_address &&
                       page_list_len      == fmr->page_list_len      &&
                       !memcmp(page_list, fmr->page_list,
                               page_list_len * sizeof *page_list))
                           return fmr;
   
           return NULL;
   }
   
   static void ib_fmr_batch_release(struct ib_fmr_pool *pool)
   {
           int                 ret;
           struct ib_pool_fmr *fmr;
           LIST_HEAD(unmap_list);
           LIST_HEAD(fmr_list);
   
           spin_lock_irq(&pool->pool_lock);
   
           list_for_each_entry(fmr, &pool->dirty_list, list) {
                   hlist_del_init(&fmr->cache_node);
                   fmr->remap_count = 0;
                   list_add_tail(&fmr->fmr->list, &fmr_list);
   
   #ifdef DEBUG
                   if (fmr->ref_count !=0) {
                           pr_warn(PFX "Unmapping FMR %p with ref count %d\n",
                                   fmr, fmr->ref_count);
                   }
   #endif
           }
   
           list_splice_init(&pool->dirty_list, &unmap_list);
           pool->dirty_len = 0;
   
           spin_unlock_irq(&pool->pool_lock);
   
           if (list_empty(&unmap_list)) {
                   return;
           }
   
           ret = ib_unmap_fmr(&fmr_list);
           if (ret)
                   pr_warn(PFX "ib_unmap_fmr returned %d\n", ret);
   
           spin_lock_irq(&pool->pool_lock);
           list_splice(&unmap_list, &pool->free_list);
           spin_unlock_irq(&pool->pool_lock);
   }
   
   static int ib_fmr_cleanup_thread(void *pool_ptr)
   {
           struct ib_fmr_pool *pool = pool_ptr;
   
           do {
                   if (atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) < 0) {
                           ib_fmr_batch_release(pool);
   
                           atomic_inc(&pool->flush_ser);
                           wake_up_interruptible(&pool->force_wait);
   
                           if (pool->flush_function)
                                   pool->flush_function(pool, pool->flush_arg);
                   }
   
                   set_current_state(TASK_INTERRUPTIBLE);
                   if (atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) >= 0 &&
                       !kthread_should_stop())
                           schedule();
                   __set_current_state(TASK_RUNNING);
           } while (!kthread_should_stop());
   
           return 0;
   }
   
   /**
    * ib_create_fmr_pool - Create an FMR pool
    * @pd:Protection domain for FMRs
    * @params:FMR pool parameters
    *
    * Create a pool of FMRs.  Return value is pointer to new pool or
    * error code if creation failed.
    */
   struct ib_fmr_pool *ib_create_fmr_pool(struct ib_pd             *pd,
                                          struct ib_fmr_pool_param *params)
   {
           struct ib_device   *device;
           struct ib_fmr_pool *pool;
           int i;
           int ret;
           int max_remaps;
   
           if (!params)
                   return ERR_PTR(-EINVAL);
   
           device = pd->device;
           if (!device->alloc_fmr    || !device->dealloc_fmr  ||
               !device->map_phys_fmr || !device->unmap_fmr) {
                   pr_info(PFX "Device %s does not support FMRs\n", device->name);
                   return ERR_PTR(-ENOSYS);
           }
   
           if (!device->attrs.max_map_per_fmr)
                   max_remaps = IB_FMR_MAX_REMAPS;
           else
                   max_remaps = device->attrs.max_map_per_fmr;
   
           pool = kmalloc(sizeof *pool, GFP_KERNEL);
           if (!pool)
                   return ERR_PTR(-ENOMEM);
   
           pool->cache_bucket   = NULL;
           pool->flush_function = params->flush_function;
           pool->flush_arg      = params->flush_arg;
   
           INIT_LIST_HEAD(&pool->free_list);
           INIT_LIST_HEAD(&pool->dirty_list);
   
           if (params->cache) {
                   pool->cache_bucket =
                           kmalloc(IB_FMR_HASH_SIZE * sizeof *pool->cache_bucket,
                                   GFP_KERNEL);
                   if (!pool->cache_bucket) {
                           pr_warn(PFX "Failed to allocate cache in pool\n");
                           ret = -ENOMEM;
                           goto out_free_pool;
                   }
   
                   for (i = 0; i < IB_FMR_HASH_SIZE; ++i)
                           INIT_HLIST_HEAD(pool->cache_bucket + i);
           }
   
           pool->pool_size       = 0;
           pool->max_pages       = params->max_pages_per_fmr;
           pool->max_remaps      = max_remaps;
           pool->dirty_watermark = params->dirty_watermark;
           pool->dirty_len       = 0;
           spin_lock_init(&pool->pool_lock);
           atomic_set(&pool->req_ser,   0);
           atomic_set(&pool->flush_ser, 0);
           init_waitqueue_head(&pool->force_wait);
   
           pool->thread = kthread_run(ib_fmr_cleanup_thread,
                                      pool,
                                      "ib_fmr(%s)",
                                      device->name);
           if (IS_ERR(pool->thread)) {
                   pr_warn(PFX "couldn't start cleanup thread\n");
                   ret = PTR_ERR(pool->thread);
                   goto out_free_pool;
           }
   
           {
                   struct ib_pool_fmr *fmr;
                   struct ib_fmr_attr fmr_attr = {
                           .max_pages  = params->max_pages_per_fmr,
                           .max_maps   = pool->max_remaps,
                           .page_shift = params->page_shift
                   };
                   int bytes_per_fmr = sizeof *fmr;
   
                   if (pool->cache_bucket)
                           bytes_per_fmr += params->max_pages_per_fmr * sizeof (u64);
   
                   for (i = 0; i < params->pool_size; ++i) {
                           fmr = kmalloc(bytes_per_fmr, GFP_KERNEL);
                           if (!fmr)
                                   goto out_fail;
   
                           fmr->pool             = pool;
                           fmr->remap_count      = 0;
                           fmr->ref_count        = 0;
                           INIT_HLIST_NODE(&fmr->cache_node);
   
                           fmr->fmr = ib_alloc_fmr(pd, params->access, &fmr_attr);
                           if (IS_ERR(fmr->fmr)) {
                                   pr_warn(PFX "fmr_create failed for FMR %d\n",
                                           i);
                                   kfree(fmr);
                                   goto out_fail;
                           }
   
                           list_add_tail(&fmr->list, &pool->free_list);
                           ++pool->pool_size;
                   }
           }
   
           return pool;
   
    out_free_pool:
           kfree(pool->cache_bucket);
           kfree(pool);
   
           return ERR_PTR(ret);
   
    out_fail:
           ib_destroy_fmr_pool(pool);
   
           return ERR_PTR(-ENOMEM);
   }
   EXPORT_SYMBOL(ib_create_fmr_pool);
   
   /**
    * ib_destroy_fmr_pool - Free FMR pool
    * @pool:FMR pool to free
    *
    * Destroy an FMR pool and free all associated resources.
    */
   void ib_destroy_fmr_pool(struct ib_fmr_pool *pool)
   {
           struct ib_pool_fmr *fmr;
           struct ib_pool_fmr *tmp;
           LIST_HEAD(fmr_list);
           int                 i;
   
           kthread_stop(pool->thread);
           ib_fmr_batch_release(pool);
   
           i = 0;
           list_for_each_entry_safe(fmr, tmp, &pool->free_list, list) {
                   if (fmr->remap_count) {
                           INIT_LIST_HEAD(&fmr_list);
                           list_add_tail(&fmr->fmr->list, &fmr_list);
                           ib_unmap_fmr(&fmr_list);
                   }
                   ib_dealloc_fmr(fmr->fmr);
                   list_del(&fmr->list);
                   kfree(fmr);
                   ++i;
           }
   
           if (i < pool->pool_size)
                   pr_warn(PFX "pool still has %d regions registered\n",
                           pool->pool_size - i);
   
           kfree(pool->cache_bucket);
           kfree(pool);
   }
   EXPORT_SYMBOL(ib_destroy_fmr_pool);
   
   /**
    * ib_flush_fmr_pool - Invalidate all unmapped FMRs
    * @pool:FMR pool to flush
    *
    * Ensure that all unmapped FMRs are fully invalidated.
    */
   int ib_flush_fmr_pool(struct ib_fmr_pool *pool)
   {
           int serial;
           struct ib_pool_fmr *fmr, *next;
   
           /*
            * The free_list holds FMRs that may have been used
            * but have not been remapped enough times to be dirty.
            * Put them on the dirty list now so that the cleanup
            * thread will reap them too.
            */
           spin_lock_irq(&pool->pool_lock);
           list_for_each_entry_safe(fmr, next, &pool->free_list, list) {
                   if (fmr->remap_count > 0)
                           list_move(&fmr->list, &pool->dirty_list);
           }
           spin_unlock_irq(&pool->pool_lock);
   
           serial = atomic_inc_return(&pool->req_ser);
           wake_up_process(pool->thread);
   
           if (wait_event_interruptible(pool->force_wait,
                                        atomic_read(&pool->flush_ser) - serial >= 0))
                   return -EINTR;
   
           return 0;
   }
   EXPORT_SYMBOL(ib_flush_fmr_pool);
   
   /**
    * ib_fmr_pool_map_phys -
    * @pool:FMR pool to allocate FMR from
    * @page_list:List of pages to map
    * @list_len:Number of pages in @page_list
    * @io_virtual_address:I/O virtual address for new FMR
    *
    * Map an FMR from an FMR pool.
    */
   struct ib_pool_fmr *ib_fmr_pool_map_phys(struct ib_fmr_pool *pool_handle,
                                            u64                *page_list,
                                            int                 list_len,
                                            u64                 io_virtual_address)
   {
           struct ib_fmr_pool *pool = pool_handle;
           struct ib_pool_fmr *fmr;
           unsigned long       flags;
           int                 result;
   
           if (list_len < 1 || list_len > pool->max_pages)
                   return ERR_PTR(-EINVAL);
   
           spin_lock_irqsave(&pool->pool_lock, flags);
           fmr = ib_fmr_cache_lookup(pool,
                                     page_list,
                                     list_len,
                                     io_virtual_address);
           if (fmr) {
                   /* found in cache */
                   ++fmr->ref_count;
                   if (fmr->ref_count == 1) {
                           list_del(&fmr->list);
                   }
   
                   spin_unlock_irqrestore(&pool->pool_lock, flags);
   
                   return fmr;
           }
   
           if (list_empty(&pool->free_list)) {
                   spin_unlock_irqrestore(&pool->pool_lock, flags);
                   return ERR_PTR(-EAGAIN);
           }
   
           fmr = list_entry(pool->free_list.next, struct ib_pool_fmr, list);
           list_del(&fmr->list);
           hlist_del_init(&fmr->cache_node);
           spin_unlock_irqrestore(&pool->pool_lock, flags);
   
           result = ib_map_phys_fmr(fmr->fmr, page_list, list_len,
                                    io_virtual_address);
   
           if (result) {
                   spin_lock_irqsave(&pool->pool_lock, flags);
                   list_add(&fmr->list, &pool->free_list);
                   spin_unlock_irqrestore(&pool->pool_lock, flags);
   
                   pr_warn(PFX "fmr_map returns %d\n", result);
   
                   return ERR_PTR(result);
           }
   
           ++fmr->remap_count;
           fmr->ref_count = 1;
   
           if (pool->cache_bucket) {
                   fmr->io_virtual_address = io_virtual_address;
                   fmr->page_list_len      = list_len;
                   memcpy(fmr->page_list, page_list, list_len * sizeof(*page_list));
   
                   spin_lock_irqsave(&pool->pool_lock, flags);
                   hlist_add_head(&fmr->cache_node,
                                  pool->cache_bucket + ib_fmr_hash(fmr->page_list[0]));
                   spin_unlock_irqrestore(&pool->pool_lock, flags);
           }
   
           return fmr;
   }
   EXPORT_SYMBOL(ib_fmr_pool_map_phys);
   
   /**
    * ib_fmr_pool_unmap - Unmap FMR
    * @fmr:FMR to unmap
    *
    * Unmap an FMR.  The FMR mapping may remain valid until the FMR is
    * reused (or until ib_flush_fmr_pool() is called).
    */
   int ib_fmr_pool_unmap(struct ib_pool_fmr *fmr)
   {
           struct ib_fmr_pool *pool;
           unsigned long flags;
   
           pool = fmr->pool;
   
           spin_lock_irqsave(&pool->pool_lock, flags);
   
           --fmr->ref_count;
           if (!fmr->ref_count) {
                   if (fmr->remap_count < pool->max_remaps) {
                           list_add_tail(&fmr->list, &pool->free_list);
                   } else {
                           list_add_tail(&fmr->list, &pool->dirty_list);
                           if (++pool->dirty_len >= pool->dirty_watermark) {
                                   atomic_inc(&pool->req_ser);
                                   wake_up_process(pool->thread);
                           }
                   }
           }
   
   #ifdef DEBUG
           if (fmr->ref_count < 0)
                   pr_warn(PFX "FMR %p has ref count %d < 0\n",
                           fmr, fmr->ref_count);
   #endif
   
           spin_unlock_irqrestore(&pool->pool_lock, flags);
   
           return 0;
   }
   EXPORT_SYMBOL(ib_fmr_pool_unmap);

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