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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/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 pages;
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;
pages = (end - start) >> umem_odp->page_shift;
if (!pages)
return -EINVAL;
umem_odp->page_list = kvcalloc(
pages, sizeof(*umem_odp->page_list), GFP_KERNEL);
if (!umem_odp->page_list)
return -ENOMEM;
umem_odp->dma_list = kvcalloc(
pages, sizeof(*umem_odp->dma_list), GFP_KERNEL);
if (!umem_odp->dma_list) {
ret = -ENOMEM;
goto out_page_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_page_list:
kvfree(umem_odp->page_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->page_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.
* @page_index: index in the umem to add the page 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. It returns
* -EAGAIN if a concurrent invalidation prevents us from updating the page.
*
* The page is released via put_page even if the operation failed. For on-demand
* pinning, the page is released whenever it isn't stored in the umem.
*/
static int ib_umem_odp_map_dma_single_page(
struct ib_umem_odp *umem_odp,
unsigned int page_index,
struct page *page,
u64 access_mask,
unsigned long current_seq)
{
struct ib_device *dev = umem_odp->umem.ibdev;
dma_addr_t dma_addr;
int ret = 0;
if (mmu_interval_check_retry(&umem_odp->notifier, current_seq)) {
ret = -EAGAIN;
goto out;
}
if (!(umem_odp->dma_list[page_index])) {
dma_addr =
ib_dma_map_page(dev, page, 0, BIT(umem_odp->page_shift),
DMA_BIDIRECTIONAL);
if (ib_dma_mapping_error(dev, dma_addr)) {
ret = -EFAULT;
goto out;
}
umem_odp->dma_list[page_index] = dma_addr | access_mask;
umem_odp->page_list[page_index] = page;
umem_odp->npages++;
} else if (umem_odp->page_list[page_index] == page) {
umem_odp->dma_list[page_index] |= access_mask;
} else {
/*
* This is a race here where we could have done:
*
* CPU0 CPU1
* get_user_pages()
* invalidate()
* page_fault()
* mutex_lock(umem_mutex)
* page from GUP != page in ODP
*
* It should be prevented by the retry test above as reading
* the seq number should be reliable under the
* umem_mutex. Thus something is really not working right if
* things get here.
*/
WARN(true,
"Got different pages in IB device and from get_user_pages. IB device page: %p, gup page: %p\n",
umem_odp->page_list[page_index], page);
ret = -EAGAIN;
}
out:
put_page(page);
return ret;
}
/**
* ib_umem_odp_map_dma_pages - Pin and DMA map userspace memory in an ODP MR.
*
* Pins the range of pages passed in the argument, and maps them to
* DMA addresses. The DMA addresses of the mapped pages is updated in
* umem_odp->dma_list.
*
* Returns the number of pages mapped in success, negative error code
* for failure.
* An -EAGAIN error code is returned when a concurrent mmu notifier prevents
* the function from completing its task.
* An -ENOENT error code indicates that userspace process is being terminated
* and mm was already destroyed.
* @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.
* @current_seq: the MMU notifiers sequance value for synchronization with
* invalidations. the sequance number is read from
* umem_odp->notifiers_seq before calling this function
*/
int ib_umem_odp_map_dma_pages(struct ib_umem_odp *umem_odp, u64 user_virt,
u64 bcnt, u64 access_mask,
unsigned long current_seq)
{
struct task_struct *owning_process = NULL;
struct mm_struct *owning_mm = umem_odp->umem.owning_mm;
struct page **local_page_list = NULL;
u64 page_mask, off;
int j, k, ret = 0, start_idx, npages = 0;
unsigned int flags = 0, page_shift;
phys_addr_t p = 0;
if (access_mask == 0)
return -EINVAL;
if (user_virt < ib_umem_start(umem_odp) ||
user_virt + bcnt > ib_umem_end(umem_odp))
return -EFAULT;
local_page_list = (struct page **)__get_free_page(GFP_KERNEL);
if (!local_page_list)
return -ENOMEM;
page_shift = umem_odp->page_shift;
page_mask = ~(BIT(page_shift) - 1);
off = user_virt & (~page_mask);
user_virt = user_virt & page_mask;
bcnt += off; /* Charge for the first page offset as well. */
/*
* 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;
}
if (access_mask & ODP_WRITE_ALLOWED_BIT)
flags |= FOLL_WRITE;
start_idx = (user_virt - ib_umem_start(umem_odp)) >> page_shift;
k = start_idx;
while (bcnt > 0) {
const size_t gup_num_pages = min_t(size_t,
ALIGN(bcnt, PAGE_SIZE) / PAGE_SIZE,
PAGE_SIZE / sizeof(struct page *));
mmap_read_lock(owning_mm);
/*
* Note: this might result in redundent page getting. We can
* avoid this by checking dma_list to be 0 before calling
* get_user_pages. However, this make the code much more
* complex (and doesn't gain us much performance in most use
* cases).
*/
npages = get_user_pages_remote(owning_mm,
user_virt, gup_num_pages,
flags, local_page_list, NULL, NULL);
mmap_read_unlock(owning_mm);
if (npages < 0) {
if (npages != -EAGAIN)
pr_warn("fail to get %zu user pages with error %d\n", gup_num_pages, npages);
else
pr_debug("fail to get %zu user pages with error %d\n", gup_num_pages, npages);
break;
}
bcnt -= min_t(size_t, npages << PAGE_SHIFT, bcnt);
mutex_lock(&umem_odp->umem_mutex);
for (j = 0; j < npages; j++, user_virt += PAGE_SIZE) {
if (user_virt & ~page_mask) {
p += PAGE_SIZE;
if (page_to_phys(local_page_list[j]) != p) {
ret = -EFAULT;
break;
}
put_page(local_page_list[j]);
continue;
}
ret = ib_umem_odp_map_dma_single_page(
umem_odp, k, local_page_list[j],
access_mask, current_seq);
if (ret < 0) {
if (ret != -EAGAIN)
pr_warn("ib_umem_odp_map_dma_single_page failed with error %d\n", ret);
else
pr_debug("ib_umem_odp_map_dma_single_page failed with error %d\n", ret);
break;
}
p = page_to_phys(local_page_list[j]);
k++;
}
mutex_unlock(&umem_odp->umem_mutex);
if (ret < 0) {
/*
* Release pages, remembering that the first page
* to hit an error was already released by
* ib_umem_odp_map_dma_single_page().
*/
if (npages - (j + 1) > 0)
release_pages(&local_page_list[j+1],
npages - (j + 1));
break;
}
}
if (ret >= 0) {
if (npages < 0 && k == start_idx)
ret = npages;
else
ret = k - start_idx;
}
mmput(owning_mm);
out_put_task:
if (owning_process)
put_task_struct(owning_process);
free_page((unsigned long)local_page_list);
return ret;
}
EXPORT_SYMBOL(ib_umem_odp_map_dma_pages);
void ib_umem_odp_unmap_dma_pages(struct ib_umem_odp *umem_odp, u64 virt,
u64 bound)
{
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));
/* Note that during the run of this function, the
* notifiers_count of the MR is > 0, preventing any racing
* faults from completion. We might be racing with other
* invalidations, so we must make sure we free each page only
* once. */
for (addr = virt; addr < bound; addr += BIT(umem_odp->page_shift)) {
idx = (addr - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
if (umem_odp->page_list[idx]) {
struct page *page = umem_odp->page_list[idx];
dma_addr_t dma = umem_odp->dma_list[idx];
dma_addr_t dma_addr = dma & ODP_DMA_ADDR_MASK;
WARN_ON(!dma_addr);
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->page_list[idx] = NULL;
umem_odp->dma_list[idx] = 0;
umem_odp->npages--;
}
}
}
EXPORT_SYMBOL(ib_umem_odp_unmap_dma_pages);
|