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/*
* Copyright (c) 2014 Mellanox Technologies. 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 <linux/types.h>
#include <linux/sched.h>
#include <linux/sched/mm.h>
#include <linux/sched/task.h>
#include <linux/pid.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/vmalloc.h>
#include <linux/hugetlb.h>
#include <linux/interval_tree.h>
#include <linux/hmm.h>
#include <linux/pagemap.h>
#include <rdma/ib_verbs.h>
#include <rdma/ib_umem.h>
#include <rdma/ib_umem_odp.h>
#include "uverbs.h"
static inline int ib_init_umem_odp(struct ib_umem_odp *umem_odp,
const struct mmu_interval_notifier_ops *ops)
{
int ret;
umem_odp->umem.is_odp = 1;
mutex_init(&umem_odp->umem_mutex);
if (!umem_odp->is_implicit_odp) {
size_t page_size = 1UL << umem_odp->page_shift;
unsigned long start;
unsigned long end;
size_t ndmas, npfns;
start = ALIGN_DOWN(umem_odp->umem.address, page_size);
if (check_add_overflow(umem_odp->umem.address,
(unsigned long)umem_odp->umem.length,
&end))
return -EOVERFLOW;
end = ALIGN(end, page_size);
if (unlikely(end < page_size))
return -EOVERFLOW;
ndmas = (end - start) >> umem_odp->page_shift;
if (!ndmas)
return -EINVAL;
npfns = (end - start) >> PAGE_SHIFT;
umem_odp->pfn_list = kvcalloc(
npfns, sizeof(*umem_odp->pfn_list), GFP_KERNEL);
if (!umem_odp->pfn_list)
return -ENOMEM;
umem_odp->dma_list = kvcalloc(
ndmas, sizeof(*umem_odp->dma_list), GFP_KERNEL);
if (!umem_odp->dma_list) {
ret = -ENOMEM;
goto out_pfn_list;
}
ret = mmu_interval_notifier_insert(&umem_odp->notifier,
umem_odp->umem.owning_mm,
start, end - start, ops);
if (ret)
goto out_dma_list;
}
return 0;
out_dma_list:
kvfree(umem_odp->dma_list);
out_pfn_list:
kvfree(umem_odp->pfn_list);
return ret;
}
/**
* ib_umem_odp_alloc_implicit - Allocate a parent implicit ODP umem
*
* Implicit ODP umems do not have a VA range and do not have any page lists.
* They exist only to hold the per_mm reference to help the driver create
* children umems.
*
* @device: IB device to create UMEM
* @access: ib_reg_mr access flags
*/
struct ib_umem_odp *ib_umem_odp_alloc_implicit(struct ib_device *device,
int access)
{
struct ib_umem *umem;
struct ib_umem_odp *umem_odp;
int ret;
if (access & IB_ACCESS_HUGETLB)
return ERR_PTR(-EINVAL);
umem_odp = kzalloc(sizeof(*umem_odp), GFP_KERNEL);
if (!umem_odp)
return ERR_PTR(-ENOMEM);
umem = &umem_odp->umem;
umem->ibdev = device;
umem->writable = ib_access_writable(access);
umem->owning_mm = current->mm;
umem_odp->is_implicit_odp = 1;
umem_odp->page_shift = PAGE_SHIFT;
umem_odp->tgid = get_task_pid(current->group_leader, PIDTYPE_PID);
ret = ib_init_umem_odp(umem_odp, NULL);
if (ret) {
put_pid(umem_odp->tgid);
kfree(umem_odp);
return ERR_PTR(ret);
}
return umem_odp;
}
EXPORT_SYMBOL(ib_umem_odp_alloc_implicit);
/**
* ib_umem_odp_alloc_child - Allocate a child ODP umem under an implicit
* parent ODP umem
*
* @root: The parent umem enclosing the child. This must be allocated using
* ib_alloc_implicit_odp_umem()
* @addr: The starting userspace VA
* @size: The length of the userspace VA
* @ops: MMU interval ops, currently only @invalidate
*/
struct ib_umem_odp *
ib_umem_odp_alloc_child(struct ib_umem_odp *root, unsigned long addr,
size_t size,
const struct mmu_interval_notifier_ops *ops)
{
/*
* Caller must ensure that root cannot be freed during the call to
* ib_alloc_odp_umem.
*/
struct ib_umem_odp *odp_data;
struct ib_umem *umem;
int ret;
if (WARN_ON(!root->is_implicit_odp))
return ERR_PTR(-EINVAL);
odp_data = kzalloc(sizeof(*odp_data), GFP_KERNEL);
if (!odp_data)
return ERR_PTR(-ENOMEM);
umem = &odp_data->umem;
umem->ibdev = root->umem.ibdev;
umem->length = size;
umem->address = addr;
umem->writable = root->umem.writable;
umem->owning_mm = root->umem.owning_mm;
odp_data->page_shift = PAGE_SHIFT;
odp_data->notifier.ops = ops;
/*
* A mmget must be held when registering a notifier, the owming_mm only
* has a mm_grab at this point.
*/
if (!mmget_not_zero(umem->owning_mm)) {
ret = -EFAULT;
goto out_free;
}
odp_data->tgid = get_pid(root->tgid);
ret = ib_init_umem_odp(odp_data, ops);
if (ret)
goto out_tgid;
mmput(umem->owning_mm);
return odp_data;
out_tgid:
put_pid(odp_data->tgid);
mmput(umem->owning_mm);
out_free:
kfree(odp_data);
return ERR_PTR(ret);
}
EXPORT_SYMBOL(ib_umem_odp_alloc_child);
/**
* ib_umem_odp_get - Create a umem_odp for a userspace va
*
* @device: IB device struct to get UMEM
* @addr: userspace virtual address to start at
* @size: length of region to pin
* @access: IB_ACCESS_xxx flags for memory being pinned
* @ops: MMU interval ops, currently only @invalidate
*
* The driver should use when the access flags indicate ODP memory. It avoids
* pinning, instead, stores the mm for future page fault handling in
* conjunction with MMU notifiers.
*/
struct ib_umem_odp *ib_umem_odp_get(struct ib_device *device,
unsigned long addr, size_t size, int access,
const struct mmu_interval_notifier_ops *ops)
{
struct ib_umem_odp *umem_odp;
struct mm_struct *mm;
int ret;
if (WARN_ON_ONCE(!(access & IB_ACCESS_ON_DEMAND)))
return ERR_PTR(-EINVAL);
umem_odp = kzalloc(sizeof(struct ib_umem_odp), GFP_KERNEL);
if (!umem_odp)
return ERR_PTR(-ENOMEM);
umem_odp->umem.ibdev = device;
umem_odp->umem.length = size;
umem_odp->umem.address = addr;
umem_odp->umem.writable = ib_access_writable(access);
umem_odp->umem.owning_mm = mm = current->mm;
umem_odp->notifier.ops = ops;
umem_odp->page_shift = PAGE_SHIFT;
#ifdef CONFIG_HUGETLB_PAGE
if (access & IB_ACCESS_HUGETLB)
umem_odp->page_shift = HPAGE_SHIFT;
#endif
umem_odp->tgid = get_task_pid(current->group_leader, PIDTYPE_PID);
ret = ib_init_umem_odp(umem_odp, ops);
if (ret)
goto err_put_pid;
return umem_odp;
err_put_pid:
put_pid(umem_odp->tgid);
kfree(umem_odp);
return ERR_PTR(ret);
}
EXPORT_SYMBOL(ib_umem_odp_get);
void ib_umem_odp_release(struct ib_umem_odp *umem_odp)
{
/*
* Ensure that no more pages are mapped in the umem.
*
* It is the driver's responsibility to ensure, before calling us,
* that the hardware will not attempt to access the MR any more.
*/
if (!umem_odp->is_implicit_odp) {
mutex_lock(&umem_odp->umem_mutex);
ib_umem_odp_unmap_dma_pages(umem_odp, ib_umem_start(umem_odp),
ib_umem_end(umem_odp));
mutex_unlock(&umem_odp->umem_mutex);
mmu_interval_notifier_remove(&umem_odp->notifier);
kvfree(umem_odp->dma_list);
kvfree(umem_odp->pfn_list);
}
put_pid(umem_odp->tgid);
kfree(umem_odp);
}
EXPORT_SYMBOL(ib_umem_odp_release);
/*
* Map for DMA and insert a single page into the on-demand paging page tables.
*
* @umem: the umem to insert the page to.
* @dma_index: index in the umem to add the dma to.
* @page: the page struct to map and add.
* @access_mask: access permissions needed for this page.
* @current_seq: sequence number for synchronization with invalidations.
* the sequence number is taken from
* umem_odp->notifiers_seq.
*
* The function returns -EFAULT if the DMA mapping operation fails.
*
*/
static int ib_umem_odp_map_dma_single_page(
struct ib_umem_odp *umem_odp,
unsigned int dma_index,
struct page *page,
u64 access_mask)
{
struct ib_device *dev = umem_odp->umem.ibdev;
dma_addr_t *dma_addr = &umem_odp->dma_list[dma_index];
if (*dma_addr) {
/*
* If the page is already dma mapped it means it went through
* a non-invalidating trasition, like read-only to writable.
* Resync the flags.
*/
*dma_addr = (*dma_addr & ODP_DMA_ADDR_MASK) | access_mask;
return 0;
}
*dma_addr = ib_dma_map_page(dev, page, 0, 1 << umem_odp->page_shift,
DMA_BIDIRECTIONAL);
if (ib_dma_mapping_error(dev, *dma_addr)) {
*dma_addr = 0;
return -EFAULT;
}
umem_odp->npages++;
*dma_addr |= access_mask;
return 0;
}
/**
* ib_umem_odp_map_dma_and_lock - DMA map userspace memory in an ODP MR and lock it.
*
* Maps the range passed in the argument to DMA addresses.
* The DMA addresses of the mapped pages is updated in umem_odp->dma_list.
* Upon success the ODP MR will be locked to let caller complete its device
* page table update.
*
* Returns the number of pages mapped in success, negative error code
* for failure.
* @umem_odp: the umem to map and pin
* @user_virt: the address from which we need to map.
* @bcnt: the minimal number of bytes to pin and map. The mapping might be
* bigger due to alignment, and may also be smaller in case of an error
* pinning or mapping a page. The actual pages mapped is returned in
* the return value.
* @access_mask: bit mask of the requested access permissions for the given
* range.
* @fault: is faulting required for the given range
*/
int ib_umem_odp_map_dma_and_lock(struct ib_umem_odp *umem_odp, u64 user_virt,
u64 bcnt, u64 access_mask, bool fault)
__acquires(&umem_odp->umem_mutex)
{
struct task_struct *owning_process = NULL;
struct mm_struct *owning_mm = umem_odp->umem.owning_mm;
int pfn_index, dma_index, ret = 0, start_idx;
unsigned int page_shift, hmm_order, pfn_start_idx;
unsigned long num_pfns, current_seq;
struct hmm_range range = {};
unsigned long timeout;
if (access_mask == 0)
return -EINVAL;
if (user_virt < ib_umem_start(umem_odp) ||
user_virt + bcnt > ib_umem_end(umem_odp))
return -EFAULT;
page_shift = umem_odp->page_shift;
/*
* owning_process is allowed to be NULL, this means somehow the mm is
* existing beyond the lifetime of the originating process.. Presumably
* mmget_not_zero will fail in this case.
*/
owning_process = get_pid_task(umem_odp->tgid, PIDTYPE_PID);
if (!owning_process || !mmget_not_zero(owning_mm)) {
ret = -EINVAL;
goto out_put_task;
}
range.notifier = &umem_odp->notifier;
range.start = ALIGN_DOWN(user_virt, 1UL << page_shift);
range.end = ALIGN(user_virt + bcnt, 1UL << page_shift);
pfn_start_idx = (range.start - ib_umem_start(umem_odp)) >> PAGE_SHIFT;
num_pfns = (range.end - range.start) >> PAGE_SHIFT;
if (fault) {
range.default_flags = HMM_PFN_REQ_FAULT;
if (access_mask & ODP_WRITE_ALLOWED_BIT)
range.default_flags |= HMM_PFN_REQ_WRITE;
}
range.hmm_pfns = &(umem_odp->pfn_list[pfn_start_idx]);
timeout = jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
retry:
current_seq = range.notifier_seq =
mmu_interval_read_begin(&umem_odp->notifier);
mmap_read_lock(owning_mm);
ret = hmm_range_fault(&range);
mmap_read_unlock(owning_mm);
if (unlikely(ret)) {
if (ret == -EBUSY && !time_after(jiffies, timeout))
goto retry;
goto out_put_mm;
}
start_idx = (range.start - ib_umem_start(umem_odp)) >> page_shift;
dma_index = start_idx;
mutex_lock(&umem_odp->umem_mutex);
if (mmu_interval_read_retry(&umem_odp->notifier, current_seq)) {
mutex_unlock(&umem_odp->umem_mutex);
goto retry;
}
for (pfn_index = 0; pfn_index < num_pfns;
pfn_index += 1 << (page_shift - PAGE_SHIFT), dma_index++) {
if (fault) {
/*
* Since we asked for hmm_range_fault() to populate
* pages it shouldn't return an error entry on success.
*/
WARN_ON(range.hmm_pfns[pfn_index] & HMM_PFN_ERROR);
WARN_ON(!(range.hmm_pfns[pfn_index] & HMM_PFN_VALID));
} else {
if (!(range.hmm_pfns[pfn_index] & HMM_PFN_VALID)) {
WARN_ON(umem_odp->dma_list[dma_index]);
continue;
}
access_mask = ODP_READ_ALLOWED_BIT;
if (range.hmm_pfns[pfn_index] & HMM_PFN_WRITE)
access_mask |= ODP_WRITE_ALLOWED_BIT;
}
hmm_order = hmm_pfn_to_map_order(range.hmm_pfns[pfn_index]);
/* If a hugepage was detected and ODP wasn't set for, the umem
* page_shift will be used, the opposite case is an error.
*/
if (hmm_order + PAGE_SHIFT < page_shift) {
ret = -EINVAL;
ibdev_dbg(umem_odp->umem.ibdev,
"%s: un-expected hmm_order %d, page_shift %d\n",
__func__, hmm_order, page_shift);
break;
}
ret = ib_umem_odp_map_dma_single_page(
umem_odp, dma_index, hmm_pfn_to_page(range.hmm_pfns[pfn_index]),
access_mask);
if (ret < 0) {
ibdev_dbg(umem_odp->umem.ibdev,
"ib_umem_odp_map_dma_single_page failed with error %d\n", ret);
break;
}
}
/* upon sucesss lock should stay on hold for the callee */
if (!ret)
ret = dma_index - start_idx;
else
mutex_unlock(&umem_odp->umem_mutex);
out_put_mm:
mmput(owning_mm);
out_put_task:
if (owning_process)
put_task_struct(owning_process);
return ret;
}
EXPORT_SYMBOL(ib_umem_odp_map_dma_and_lock);
void ib_umem_odp_unmap_dma_pages(struct ib_umem_odp *umem_odp, u64 virt,
u64 bound)
{
dma_addr_t dma_addr;
dma_addr_t dma;
int idx;
u64 addr;
struct ib_device *dev = umem_odp->umem.ibdev;
lockdep_assert_held(&umem_odp->umem_mutex);
virt = max_t(u64, virt, ib_umem_start(umem_odp));
bound = min_t(u64, bound, ib_umem_end(umem_odp));
for (addr = virt; addr < bound; addr += BIT(umem_odp->page_shift)) {
idx = (addr - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
dma = umem_odp->dma_list[idx];
/* The access flags guaranteed a valid DMA address in case was NULL */
if (dma) {
unsigned long pfn_idx = (addr - ib_umem_start(umem_odp)) >> PAGE_SHIFT;
struct page *page = hmm_pfn_to_page(umem_odp->pfn_list[pfn_idx]);
dma_addr = dma & ODP_DMA_ADDR_MASK;
ib_dma_unmap_page(dev, dma_addr,
BIT(umem_odp->page_shift),
DMA_BIDIRECTIONAL);
if (dma & ODP_WRITE_ALLOWED_BIT) {
struct page *head_page = compound_head(page);
/*
* set_page_dirty prefers being called with
* the page lock. However, MMU notifiers are
* called sometimes with and sometimes without
* the lock. We rely on the umem_mutex instead
* to prevent other mmu notifiers from
* continuing and allowing the page mapping to
* be removed.
*/
set_page_dirty(head_page);
}
umem_odp->dma_list[idx] = 0;
umem_odp->npages--;
}
}
}
EXPORT_SYMBOL(ib_umem_odp_unmap_dma_pages);