/*
* @put_userptr: inform the allocator that a USERPTR buffer will no longer
* be used
*/
static void vb2_dma_sg_put_userptr(void *buf_priv)
{
struct vb2_dma_sg_buf *buf = buf_priv;
struct sg_table *sgt = &buf->sg_table;
int i = buf->num_pages;
DEFINE_DMA_ATTRS(attrs);
#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,6,0)
dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
#endif
dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
__func__, buf->num_pages);
dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir,
&attrs);
if (buf->vaddr)
vm_unmap_ram(buf->vaddr, buf->num_pages);
sg_free_table(buf->dma_sgt);
while (--i >= 0) {
if (buf->dma_dir == DMA_FROM_DEVICE)
set_page_dirty_lock(buf->pages[i]);
if (!vma_is_io(buf->vma))
put_page(buf->pages[i]);
}
kfree(buf->pages);
vb2_put_vma(buf->vma);
kfree(buf);
}
static void drm_ttm_free_user_pages(struct drm_ttm *ttm)
{
int write;
int dirty;
struct page *page;
int i;
BUG_ON(!(ttm->page_flags & DRM_TTM_PAGE_USER));
write = ((ttm->page_flags & DRM_TTM_PAGE_USER_WRITE) != 0);
dirty = ((ttm->page_flags & DRM_TTM_PAGE_USER_DIRTY) != 0);
for (i = 0; i < ttm->num_pages; ++i) {
page = ttm->pages[i];
if (page == NULL)
continue;
if (page == ttm->dummy_read_page) {
BUG_ON(write);
continue;
}
if (write && dirty && !PageReserved(page))
set_page_dirty_lock(page);
ttm->pages[i] = NULL;
put_page(page);
}
}
/**
* process_vm_rw_pages - read/write pages from task specified
* @pages: array of pointers to pages we want to copy
* @start_offset: offset in page to start copying from/to
* @len: number of bytes to copy
* @iter: where to copy to/from locally
* @vm_write: 0 means copy from, 1 means copy to
* Returns 0 on success, error code otherwise
*/
static int process_vm_rw_pages(struct page **pages,
unsigned offset,
size_t len,
struct iov_iter *iter,
int vm_write)
{
/* Do the copy for each page */
while (len && iov_iter_count(iter)) {
struct page *page = *pages++;
size_t copy = PAGE_SIZE - offset;
size_t copied;
if (copy > len)
copy = len;
if (vm_write) {
copied = copy_page_from_iter(page, offset, copy, iter);
set_page_dirty_lock(page);
} else {
copied = copy_page_to_iter(page, offset, copy, iter);
}
len -= copied;
if (copied < copy && iov_iter_count(iter))
return -EFAULT;
offset = 0;
}
return 0;
}
unsigned long __copy_to_user_ll(void __user *to, const void *from,
unsigned long n)
{
BUG_ON((long) n < 0);
#ifndef CONFIG_X86_WP_WORKS_OK
if (unlikely(boot_cpu_data.wp_works_ok == 0) &&
((unsigned long )to) < TASK_SIZE) {
/*
* CPU does not honor the WP bit when writing
* from supervisory mode, and due to preemption or SMP,
* the page tables can change at any time.
* Do it manually. Manfred <*****@*****.**>
*/
while (n) {
unsigned long offset = ((unsigned long)to)%PAGE_SIZE;
unsigned long len = PAGE_SIZE - offset;
int retval;
struct page *pg;
void *maddr;
if (len > n)
len = n;
survive:
down_read(¤t->mm->mmap_sem);
retval = get_user_pages(current, current->mm,
(unsigned long )to, 1, 1, 0, &pg, NULL);
if (retval == -ENOMEM && current->pid == 1) {
up_read(¤t->mm->mmap_sem);
blk_congestion_wait(WRITE, HZ/50);
goto survive;
}
if (retval != 1) {
up_read(¤t->mm->mmap_sem);
break;
}
maddr = kmap_atomic(pg, KM_USER0);
memcpy(maddr + offset, from, len);
kunmap_atomic(maddr, KM_USER0);
set_page_dirty_lock(pg);
put_page(pg);
up_read(¤t->mm->mmap_sem);
from += len;
to += len;
n -= len;
}
return n;
}
#endif
if (movsl_is_ok(to, from, n))
__copy_user(to, from, n);
else
n = __copy_user_intel(to, from, n);
return n;
}
static void free_ept_page(epte_t epte)
{
struct page *page = pfn_to_page(epte_addr(epte) >> PAGE_SHIFT);
if (epte & __EPTE_WRITE)
set_page_dirty_lock(page);
put_page(page);
}
unsigned long __copy_to_user_ll(void __user *to, const void *from,
unsigned long n)
{
#ifndef CONFIG_X86_WP_WORKS_OK
if (unlikely(boot_cpu_data.wp_works_ok == 0) &&
((unsigned long)to) < TASK_SIZE) {
if (in_atomic())
return n;
while (n) {
unsigned long offset = ((unsigned long)to)%PAGE_SIZE;
unsigned long len = PAGE_SIZE - offset;
int retval;
struct page *pg;
void *maddr;
if (len > n)
len = n;
survive:
down_read(¤t->mm->mmap_sem);
retval = get_user_pages(current, current->mm,
(unsigned long)to, 1, 1, 0, &pg, NULL);
if (retval == -ENOMEM && is_global_init(current)) {
up_read(¤t->mm->mmap_sem);
congestion_wait(BLK_RW_ASYNC, HZ/50);
goto survive;
}
if (retval != 1) {
up_read(¤t->mm->mmap_sem);
break;
}
maddr = kmap_atomic(pg, KM_USER0);
memcpy(maddr + offset, from, len);
kunmap_atomic(maddr, KM_USER0);
set_page_dirty_lock(pg);
put_page(pg);
up_read(¤t->mm->mmap_sem);
from += len;
to += len;
n -= len;
}
return n;
}
#endif
if (movsl_is_ok(to, from, n))
__copy_user(to, from, n);
else
n = __copy_user_intel(to, from, n);
return n;
}
/**
* nfs_free_user_pages - tear down page struct array
* @pages: array of page struct pointers underlying target buffer
*/
static void
nfs_free_user_pages(struct page **pages, int npages, int do_dirty)
{
int i;
for (i = 0; i < npages; i++) {
if (do_dirty)
set_page_dirty_lock(pages[i]);
page_cache_release(pages[i]);
}
kfree(pages);
}
void ceph_put_page_vector(struct page **pages, int num_pages, bool dirty)
{
int i;
for (i = 0; i < num_pages; i++) {
if (dirty)
set_page_dirty_lock(pages[i]);
put_page(pages[i]);
}
kvfree(pages);
}
static void fuse_release_user_pages(struct fuse_req *req, int write)
{
unsigned i;
for (i = 0; i < req->num_pages; i++) {
struct page *page = req->pages[i];
if (write)
set_page_dirty_lock(page);
put_page(page);
}
}
static void __qib_release_user_pages(struct page **p, size_t num_pages,
int dirty)
{
size_t i;
for (i = 0; i < num_pages; i++) {
if (dirty)
set_page_dirty_lock(p[i]);
put_page(p[i]);
}
}
static void free_ept_page(epte_t epte)
{
struct page *page = pfn_to_page(epte_addr(epte) >> PAGE_SHIFT);
/* PFN mapppings are not backed by pages. */
if (epte & __EPTE_PFNMAP)
return;
if (epte & __EPTE_WRITE)
set_page_dirty_lock(page);
put_page(page);
}
/* Unmap and put previous page of userspace buffer */
static void fuse_copy_finish(struct fuse_copy_state *cs)
{
if (cs->mapaddr) {
kunmap_atomic(cs->mapaddr, KM_USER0);
if (cs->write) {
flush_dcache_page(cs->pg);
set_page_dirty_lock(cs->pg);
}
put_page(cs->pg);
cs->mapaddr = NULL;
}
}
static int cfs_access_process_vm(struct task_struct *tsk,
struct mm_struct *mm,
unsigned long addr,
void *buf, int len, int write)
{
/* Just copied from kernel for the kernels which doesn't
* have access_process_vm() exported */
struct vm_area_struct *vma;
struct page *page;
void *old_buf = buf;
/* Avoid deadlocks on mmap_sem if called from sys_mmap_pgoff(),
* which is already holding mmap_sem for writes. If some other
* thread gets the write lock in the meantime, this thread will
* block, but at least it won't deadlock on itself. LU-1735 */
if (down_read_trylock(&mm->mmap_sem) == 0)
return -EDEADLK;
/* ignore errors, just check how much was successfully transferred */
while (len) {
int bytes, rc, offset;
void *maddr;
rc = get_user_pages(tsk, mm, addr, 1,
write, 1, &page, &vma);
if (rc <= 0)
break;
bytes = len;
offset = addr & (PAGE_SIZE-1);
if (bytes > PAGE_SIZE-offset)
bytes = PAGE_SIZE-offset;
maddr = kmap(page);
if (write) {
copy_to_user_page(vma, page, addr,
maddr + offset, buf, bytes);
set_page_dirty_lock(page);
} else {
copy_from_user_page(vma, page, addr,
buf, maddr + offset, bytes);
}
kunmap(page);
page_cache_release(page);
len -= bytes;
buf += bytes;
addr += bytes;
}
up_read(&mm->mmap_sem);
return buf - old_buf;
}
static void __qib_release_user_pages(struct page **p, size_t num_pages,
int dirty)
{
size_t i;
for (i = 0; i < num_pages; i++) {
qib_cdbg(MM, "%lu/%lu put_page %p\n", (unsigned long) i,
(unsigned long) num_pages, p[i]);
if (dirty)
set_page_dirty_lock(p[i]);
put_page(p[i]);
}
}
static int cfs_access_process_vm(struct task_struct *tsk, unsigned long addr,
void *buf, int len, int write)
{
/* Just copied from kernel for the kernels which doesn't
* have access_process_vm() exported */
struct mm_struct *mm;
struct vm_area_struct *vma;
struct page *page;
void *old_buf = buf;
mm = get_task_mm(tsk);
if (!mm)
return 0;
down_read(&mm->mmap_sem);
/* ignore errors, just check how much was sucessfully transfered */
while (len) {
int bytes, rc, offset;
void *maddr;
rc = get_user_pages(tsk, mm, addr, 1,
write, 1, &page, &vma);
if (rc <= 0)
break;
bytes = len;
offset = addr & (PAGE_SIZE-1);
if (bytes > PAGE_SIZE-offset)
bytes = PAGE_SIZE-offset;
maddr = kmap(page);
if (write) {
copy_to_user_page(vma, page, addr,
maddr + offset, buf, bytes);
set_page_dirty_lock(page);
} else {
copy_from_user_page(vma, page, addr,
buf, maddr + offset, bytes);
}
kunmap(page);
page_cache_release(page);
len -= bytes;
buf += bytes;
addr += bytes;
}
up_read(&mm->mmap_sem);
mmput(mm);
return buf - old_buf;
}
void dma_unpin_iovec_pages(struct dma_pinned_list *pinned_list)
{
int i, j;
if (!pinned_list)
return;
for (i = 0; i < pinned_list->nr_iovecs; i++) {
struct dma_page_list *page_list = &pinned_list->page_list[i];
for (j = 0; j < page_list->nr_pages; j++) {
set_page_dirty_lock(page_list->pages[j]);
page_cache_release(page_list->pages[j]);
}
}
kfree(pinned_list);
}
/* ll_free_user_pages - tear down page struct array
* @pages: array of page struct pointers underlying target buffer */
static void ll_free_user_pages(struct page **pages, int npages, int do_dirty)
{
int i;
for (i = 0; i < npages; i++) {
if (pages[i] == NULL)
break;
if (do_dirty)
set_page_dirty_lock(pages[i]);
put_page(pages[i]);
}
#if defined(HAVE_DIRECTIO_ITER) || defined(HAVE_IOV_ITER_RW)
kvfree(pages);
#else
OBD_FREE_LARGE(pages, npages * sizeof(*pages));
#endif
}
/* TODO: This is really inefficient. We need something like get_user()
* (instruction directly accesses the data, with an exception table entry
* returning -EFAULT). See Documentation/x86/exception-tables.txt.
*/
static int set_bit_to_user(int nr, void __user *addr)
{
unsigned long log = (unsigned long)addr;
struct page *page;
void *base;
int bit = nr + (log % PAGE_SIZE) * 8;
int r;
r = get_user_pages_fast(log, 1, 1, &page);
if (r < 0)
return r;
BUG_ON(r != 1);
base = kmap_atomic(page, KM_USER0);
set_bit(bit, base);
kunmap_atomic(base, KM_USER0);
set_page_dirty_lock(page);
put_page(page);
return 0;
}
static void EplApiProcessImagePutUserPages(
struct page** ppPage_p, BOOL fDirty_p)
{
unsigned int nIndex;
for (nIndex = 0; nIndex < EPL_API_PI_PAGE_COUNT; nIndex++)
{
if (ppPage_p[nIndex] == NULL)
{
break;
}
if (fDirty_p != FALSE)
{
set_page_dirty_lock(ppPage_p[nIndex]);
}
put_page(ppPage_p[nIndex]);
ppPage_p[nIndex] = NULL;
}
}
/*
* @put_userptr: inform the allocator that a USERPTR buffer will no longer
* be used
*/
static void vb2_dma_sg_put_userptr(void *buf_priv)
{
struct vb2_dma_sg_buf *buf = buf_priv;
int i = buf->num_pages;
dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
__func__, buf->num_pages);
if (buf->vaddr)
vm_unmap_ram(buf->vaddr, buf->num_pages);
sg_free_table(&buf->sg_table);
while (--i >= 0) {
if (buf->write)
set_page_dirty_lock(buf->pages[i]);
if (!vma_is_io(buf->vma))
put_page(buf->pages[i]);
}
kfree(buf->pages);
vb2_put_vma(buf->vma);
kfree(buf);
}
static void vb2_vmalloc_put_userptr(void *buf_priv)
{
struct vb2_vmalloc_buf *buf = buf_priv;
unsigned long vaddr = (unsigned long)buf->vaddr & PAGE_MASK;
unsigned int i;
if (buf->pages) {
if (vaddr)
vm_unmap_ram((void *)vaddr, buf->n_pages);
for (i = 0; i < buf->n_pages; ++i) {
if (buf->dma_dir == DMA_FROM_DEVICE)
set_page_dirty_lock(buf->pages[i]);
put_page(buf->pages[i]);
}
kfree(buf->pages);
} else {
vb2_put_vma(buf->vma);
iounmap((__force void __iomem *)buf->vaddr);
}
kfree(buf);
}
static void vb2_vmalloc_put_userptr(void *buf_priv)
{
struct vb2_vmalloc_buf *buf = buf_priv;
unsigned long vaddr = (unsigned long)buf->vaddr & PAGE_MASK;
unsigned int i;
struct page **pages;
unsigned int n_pages;
if (!buf->vec->is_pfns) {
n_pages = frame_vector_count(buf->vec);
pages = frame_vector_pages(buf->vec);
if (vaddr)
vm_unmap_ram((void *)vaddr, n_pages);
if (buf->dma_dir == DMA_FROM_DEVICE)
for (i = 0; i < n_pages; i++)
set_page_dirty_lock(pages[i]);
} else {
iounmap((__force void __iomem *)buf->vaddr);
}
vb2_destroy_framevec(buf->vec);
kfree(buf);
}
static void vb2_vmalloc_put_userptr(void *buf_priv)
{
struct vb2_vmalloc_buf *buf = buf_priv;
unsigned long vaddr = (unsigned long)buf->vaddr & PAGE_MASK;
unsigned int i;
if (buf->pages) {
if (vaddr)
vm_unmap_ram((void *)vaddr, buf->n_pages);
for (i = 0; i < buf->n_pages; ++i) {
if (buf->write)
set_page_dirty_lock(buf->pages[i]);
put_page(buf->pages[i]);
}
kfree(buf->pages);
} else {
if (buf->vma)
vb2_put_vma(buf->vma);
iounmap(buf->vaddr);
}
kfree(buf);
}
/*
* @put_userptr: inform the allocator that a USERPTR buffer will no longer
* be used
*/
static void vb2_dma_sg_put_userptr(void *buf_priv)
{
struct vb2_dma_sg_buf *buf = buf_priv;
struct sg_table *sgt = &buf->sg_table;
int i = buf->num_pages;
DEFINE_DMA_ATTRS(attrs);
dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
__func__, buf->num_pages);
dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir,
&attrs);
if (buf->vaddr)
vm_unmap_ram(buf->vaddr, buf->num_pages);
sg_free_table(buf->dma_sgt);
while (--i >= 0) {
if (buf->dma_dir == DMA_FROM_DEVICE)
set_page_dirty_lock(buf->pages[i]);
}
vb2_destroy_framevec(buf->vec);
kfree(buf);
}
static void ttm_tt_free_user_pages(struct ttm_tt *ttm)
{
int write;
int dirty;
struct page *page;
int i;
struct ttm_backend *be = ttm->be;
BUG_ON(!(ttm->page_flags & TTM_PAGE_FLAG_USER));
write = ((ttm->page_flags & TTM_PAGE_FLAG_WRITE) != 0);
dirty = ((ttm->page_flags & TTM_PAGE_FLAG_USER_DIRTY) != 0);
if (be)
be->func->clear(be);
for (i = 0; i < ttm->num_pages; ++i) {
page = ttm->pages[i];
if (page == NULL)
continue;
if (page == ttm->dummy_read_page) {
BUG_ON(write);
continue;
}
if (write && dirty && !PageReserved(page))
set_page_dirty_lock(page);
ttm->pages[i] = NULL;
ttm_mem_global_free(ttm->glob->mem_glob, PAGE_SIZE);
put_page(page);
}
ttm->state = tt_unpopulated;
ttm->first_himem_page = ttm->num_pages;
ttm->last_lomem_page = -1;
}
/* pvfs_bufmap_copy_to_user_task_iovec()
*
* copies data out of a mapped buffer to a vector of user space address
* of a given task specified by the task structure argument (tsk)
* This is used by the client-daemon for completing an aio
* operation that was issued by an arbitrary user program.
* Unfortunately, we cannot use a copy_to_user
* in that case and need to map in the user pages before
* attempting the copy!
*
* NOTE: There is no need for an analogous copy from user task since
* the data buffers get copied in the context of the process initiating
* the write system call!
*
* Returns number of bytes copied on success, -errno on failure.
*/
size_t pvfs_bufmap_copy_to_user_task_iovec(
struct task_struct *tsk,
struct iovec *iovec, unsigned long nr_segs,
int buffer_index,
size_t size_to_be_copied)
{
size_t ret = 0, amt_copied = 0, cur_copy_size = 0;
int from_page_index = 0;
void *from_kaddr = NULL;
struct iovec *copied_iovec = NULL;
struct pvfs_bufmap_desc *from = &desc_array[buffer_index];
struct mm_struct *mm = NULL;
struct vm_area_struct *vma = NULL;
struct page *page = NULL;
unsigned long to_addr = 0;
void *maddr = NULL;
unsigned int to_offset = 0;
unsigned int seg, from_page_offset = 0;
gossip_debug(GOSSIP_BUFMAP_DEBUG, "pvfs_bufmap_copy_to_user_task_iovec: "
" PID: %d, iovec %p, from %p, index %d, "
" size %zd\n", tsk->pid, iovec, from, buffer_index, size_to_be_copied);
down_read(&bufmap_init_sem);
if (bufmap_init == 0)
{
gossip_err("pvfs2_bufmap_copy_to_user: not yet "
"initialized.\n");
gossip_err("pvfs2: please confirm that pvfs2-client "
"daemon is running.\n");
up_read(&bufmap_init_sem);
return -EIO;
}
/*
* copy the passed in iovec so that we can change some of its fields
*/
copied_iovec = kmalloc(nr_segs * sizeof(*copied_iovec),
PVFS2_BUFMAP_GFP_FLAGS);
if (copied_iovec == NULL)
{
gossip_err("pvfs_bufmap_copy_to_user_iovec: failed allocating memory\n");
up_read(&bufmap_init_sem);
return -ENOMEM;
}
memcpy(copied_iovec, iovec, nr_segs * sizeof(*copied_iovec));
/*
* Go through each segment in the iovec and make sure that
* the summation of iov_len is greater than the given size.
*/
for (seg = 0, amt_copied = 0; seg < nr_segs; seg++)
{
amt_copied += copied_iovec[seg].iov_len;
}
if (amt_copied < size_to_be_copied)
{
gossip_err("pvfs_bufmap_copy_to_user_task_iovec: computed total (%zd) "
"is less than (%zd)\n", amt_copied, size_to_be_copied);
kfree(copied_iovec);
up_read(&bufmap_init_sem);
return -EINVAL;
}
mm = get_task_mm(tsk);
if (!mm)
{
kfree(copied_iovec);
up_read(&bufmap_init_sem);
return -EIO;
}
from_page_index = 0;
amt_copied = 0;
seg = 0;
from_page_offset = 0;
/*
* Go through each of the page in the specified process
* address space and copy from the mapped
* buffer, and make sure to do this one page at a time!
*/
down_read(&mm->mmap_sem);
while (amt_copied < size_to_be_copied)
{
int inc_from_page_index = 0;
struct iovec *iv = &copied_iovec[seg];
if (iv->iov_len < (PAGE_SIZE - from_page_offset))
{
cur_copy_size = PVFS_util_min(iv->iov_len, size_to_be_copied - amt_copied);
seg++;
to_addr = (unsigned long) iv->iov_base;
inc_from_page_index = 0;
}
else if (iv->iov_len == (PAGE_SIZE - from_page_offset))
{
cur_copy_size = PVFS_util_min(iv->iov_len, size_to_be_copied - amt_copied);
seg++;
to_addr = (unsigned long) iv->iov_base;
inc_from_page_index = 1;
}
else
{
cur_copy_size = PVFS_util_min(PAGE_SIZE - from_page_offset, size_to_be_copied - amt_copied);
to_addr = (unsigned long) iv->iov_base;
iv->iov_base += cur_copy_size;
iv->iov_len -= cur_copy_size;
inc_from_page_index = 1;
}
ret = get_user_pages(tsk, mm, to_addr,
1,/* count */
1,/* write */
1,/* force */
&page, &vma);
if (ret <= 0)
break;
to_offset = to_addr & (PAGE_SIZE - 1);
maddr = pvfs2_kmap(page);
from_kaddr = pvfs2_kmap(from->page_array[from_page_index]);
copy_to_user_page(vma, page, to_addr,
maddr + to_offset /* dst */,
from_kaddr + from_page_offset, /* src */
cur_copy_size /* len */);
set_page_dirty_lock(page);
pvfs2_kunmap(from->page_array[from_page_index]);
pvfs2_kunmap(page);
page_cache_release(page);
amt_copied += cur_copy_size;
if (inc_from_page_index)
{
from_page_offset = 0;
from_page_index++;
}
else
{
from_page_offset += cur_copy_size;
}
}
up_read(&mm->mmap_sem);
mmput(mm);
up_read(&bufmap_init_sem);
kfree(copied_iovec);
return (amt_copied < size_to_be_copied) ? -EFAULT: amt_copied;
}
int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
{
struct mm_struct *mm;
struct vm_area_struct *vma;
struct page *page;
void *old_buf = buf;
mm = get_task_mm(tsk);
if (!mm)
return 0;
down_read(&mm->mmap_sem);
/* ignore errors, just check how much was sucessfully transfered */
while (len) {
int bytes, ret, offset;
void *maddr;
unsigned long paddr;
int xip = 0;
#ifdef CONFIG_CRAMFS_XIP_DEBUGGABLE
if (xip_enable_debug && !write) {
vma = find_extend_vma(mm, addr);
if (vma && (vma->vm_flags & VM_XIP))
xip = find_xip_untouched_entry(mm, addr, &paddr);
}
#endif
if (xip) {
maddr = ioremap(paddr, PAGE_SIZE);
if (!maddr)
break;
page = NULL;
} else {
ret = get_user_pages(tsk, mm, addr, 1,
write, 1, &page, &vma);
if (ret <= 0)
break;
maddr = kmap(page);
}
bytes = len;
offset = addr & (PAGE_SIZE-1);
if (bytes > PAGE_SIZE-offset)
bytes = PAGE_SIZE-offset;
if (write) {
copy_to_user_page(vma, page, addr,
maddr + offset, buf, bytes);
set_page_dirty_lock(page);
} else {
copy_from_user_page(vma, page, addr,
buf, maddr + offset, bytes);
}
if (xip)
iounmap(maddr);
else {
kunmap(page);
page_cache_release(page);
}
len -= bytes;
buf += bytes;
addr += bytes;
}
up_read(&mm->mmap_sem);
mmput(mm);
return buf - old_buf;
}
/**
* process_vm_rw_pages - read/write pages from task specified
* @task: task to read/write from
* @mm: mm for task
* @process_pages: struct pages area that can store at least
* nr_pages_to_copy struct page pointers
* @pa: address of page in task to start copying from/to
* @start_offset: offset in page to start copying from/to
* @len: number of bytes to copy
* @lvec: iovec array specifying where to copy to/from
* @lvec_cnt: number of elements in iovec array
* @lvec_current: index in iovec array we are up to
* @lvec_offset: offset in bytes from current iovec iov_base we are up to
* @vm_write: 0 means copy from, 1 means copy to
* @nr_pages_to_copy: number of pages to copy
* @bytes_copied: returns number of bytes successfully copied
* Returns 0 on success, error code otherwise
*/
static int process_vm_rw_pages(struct task_struct *task,
struct mm_struct *mm,
struct page **process_pages,
unsigned long pa,
unsigned long start_offset,
unsigned long len,
const struct iovec *lvec,
unsigned long lvec_cnt,
unsigned long *lvec_current,
size_t *lvec_offset,
int vm_write,
unsigned int nr_pages_to_copy,
ssize_t *bytes_copied)
{
int pages_pinned;
void *target_kaddr;
int pgs_copied = 0;
int j;
int ret;
ssize_t bytes_to_copy;
ssize_t rc = 0;
*bytes_copied = 0;
/* Get the pages we're interested in */
down_read(&mm->mmap_sem);
pages_pinned = get_user_pages(task, mm, pa,
nr_pages_to_copy,
vm_write, 0, process_pages, NULL);
up_read(&mm->mmap_sem);
if (pages_pinned != nr_pages_to_copy) {
rc = -EFAULT;
goto end;
}
/* Do the copy for each page */
for (pgs_copied = 0;
(pgs_copied < nr_pages_to_copy) && (*lvec_current < lvec_cnt);
pgs_copied++) {
/* Make sure we have a non zero length iovec */
while (*lvec_current < lvec_cnt
&& lvec[*lvec_current].iov_len == 0)
(*lvec_current)++;
if (*lvec_current == lvec_cnt)
break;
/*
* Will copy smallest of:
* - bytes remaining in page
* - bytes remaining in destination iovec
*/
bytes_to_copy = min_t(ssize_t, PAGE_SIZE - start_offset,
len - *bytes_copied);
bytes_to_copy = min_t(ssize_t, bytes_to_copy,
lvec[*lvec_current].iov_len
- *lvec_offset);
target_kaddr = kmap(process_pages[pgs_copied]) + start_offset;
if (vm_write)
ret = copy_from_user(target_kaddr,
lvec[*lvec_current].iov_base
+ *lvec_offset,
bytes_to_copy);
else
ret = copy_to_user(lvec[*lvec_current].iov_base
+ *lvec_offset,
target_kaddr, bytes_to_copy);
kunmap(process_pages[pgs_copied]);
if (ret) {
*bytes_copied += bytes_to_copy - ret;
pgs_copied++;
rc = -EFAULT;
goto end;
}
*bytes_copied += bytes_to_copy;
*lvec_offset += bytes_to_copy;
if (*lvec_offset == lvec[*lvec_current].iov_len) {
/*
* Need to copy remaining part of page into the
* next iovec if there are any bytes left in page
*/
(*lvec_current)++;
*lvec_offset = 0;
start_offset = (start_offset + bytes_to_copy)
% PAGE_SIZE;
if (start_offset)
pgs_copied--;
} else {
start_offset = 0;
}
}
end:
if (vm_write) {
for (j = 0; j < pages_pinned; j++) {
if (j < pgs_copied)
set_page_dirty_lock(process_pages[j]);
put_page(process_pages[j]);
}
} else {
for (j = 0; j < pages_pinned; j++)
put_page(process_pages[j]);
}
return rc;
}
