mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-06 21:46:39 +07:00
62a8067a7f
New variant of iov_iter - ITER_BVEC in iter->type, backed with bio_vec array instead of iovec one. Primitives taught to deal with such beasts, __swap_write() switched to using that kind of iov_iter. Note that bio_vec is just a <page, offset, length> triple - there's nothing block-specific about it. I've left the definition where it was, but took it from under ifdef CONFIG_BLOCK. Next target: ->splice_write()... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
744 lines
17 KiB
C
744 lines
17 KiB
C
#include <linux/export.h>
|
|
#include <linux/uio.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/vmalloc.h>
|
|
|
|
static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes,
|
|
struct iov_iter *i)
|
|
{
|
|
size_t skip, copy, left, wanted;
|
|
const struct iovec *iov;
|
|
char __user *buf;
|
|
void *kaddr, *from;
|
|
|
|
if (unlikely(bytes > i->count))
|
|
bytes = i->count;
|
|
|
|
if (unlikely(!bytes))
|
|
return 0;
|
|
|
|
wanted = bytes;
|
|
iov = i->iov;
|
|
skip = i->iov_offset;
|
|
buf = iov->iov_base + skip;
|
|
copy = min(bytes, iov->iov_len - skip);
|
|
|
|
if (!fault_in_pages_writeable(buf, copy)) {
|
|
kaddr = kmap_atomic(page);
|
|
from = kaddr + offset;
|
|
|
|
/* first chunk, usually the only one */
|
|
left = __copy_to_user_inatomic(buf, from, copy);
|
|
copy -= left;
|
|
skip += copy;
|
|
from += copy;
|
|
bytes -= copy;
|
|
|
|
while (unlikely(!left && bytes)) {
|
|
iov++;
|
|
buf = iov->iov_base;
|
|
copy = min(bytes, iov->iov_len);
|
|
left = __copy_to_user_inatomic(buf, from, copy);
|
|
copy -= left;
|
|
skip = copy;
|
|
from += copy;
|
|
bytes -= copy;
|
|
}
|
|
if (likely(!bytes)) {
|
|
kunmap_atomic(kaddr);
|
|
goto done;
|
|
}
|
|
offset = from - kaddr;
|
|
buf += copy;
|
|
kunmap_atomic(kaddr);
|
|
copy = min(bytes, iov->iov_len - skip);
|
|
}
|
|
/* Too bad - revert to non-atomic kmap */
|
|
kaddr = kmap(page);
|
|
from = kaddr + offset;
|
|
left = __copy_to_user(buf, from, copy);
|
|
copy -= left;
|
|
skip += copy;
|
|
from += copy;
|
|
bytes -= copy;
|
|
while (unlikely(!left && bytes)) {
|
|
iov++;
|
|
buf = iov->iov_base;
|
|
copy = min(bytes, iov->iov_len);
|
|
left = __copy_to_user(buf, from, copy);
|
|
copy -= left;
|
|
skip = copy;
|
|
from += copy;
|
|
bytes -= copy;
|
|
}
|
|
kunmap(page);
|
|
done:
|
|
if (skip == iov->iov_len) {
|
|
iov++;
|
|
skip = 0;
|
|
}
|
|
i->count -= wanted - bytes;
|
|
i->nr_segs -= iov - i->iov;
|
|
i->iov = iov;
|
|
i->iov_offset = skip;
|
|
return wanted - bytes;
|
|
}
|
|
|
|
static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes,
|
|
struct iov_iter *i)
|
|
{
|
|
size_t skip, copy, left, wanted;
|
|
const struct iovec *iov;
|
|
char __user *buf;
|
|
void *kaddr, *to;
|
|
|
|
if (unlikely(bytes > i->count))
|
|
bytes = i->count;
|
|
|
|
if (unlikely(!bytes))
|
|
return 0;
|
|
|
|
wanted = bytes;
|
|
iov = i->iov;
|
|
skip = i->iov_offset;
|
|
buf = iov->iov_base + skip;
|
|
copy = min(bytes, iov->iov_len - skip);
|
|
|
|
if (!fault_in_pages_readable(buf, copy)) {
|
|
kaddr = kmap_atomic(page);
|
|
to = kaddr + offset;
|
|
|
|
/* first chunk, usually the only one */
|
|
left = __copy_from_user_inatomic(to, buf, copy);
|
|
copy -= left;
|
|
skip += copy;
|
|
to += copy;
|
|
bytes -= copy;
|
|
|
|
while (unlikely(!left && bytes)) {
|
|
iov++;
|
|
buf = iov->iov_base;
|
|
copy = min(bytes, iov->iov_len);
|
|
left = __copy_from_user_inatomic(to, buf, copy);
|
|
copy -= left;
|
|
skip = copy;
|
|
to += copy;
|
|
bytes -= copy;
|
|
}
|
|
if (likely(!bytes)) {
|
|
kunmap_atomic(kaddr);
|
|
goto done;
|
|
}
|
|
offset = to - kaddr;
|
|
buf += copy;
|
|
kunmap_atomic(kaddr);
|
|
copy = min(bytes, iov->iov_len - skip);
|
|
}
|
|
/* Too bad - revert to non-atomic kmap */
|
|
kaddr = kmap(page);
|
|
to = kaddr + offset;
|
|
left = __copy_from_user(to, buf, copy);
|
|
copy -= left;
|
|
skip += copy;
|
|
to += copy;
|
|
bytes -= copy;
|
|
while (unlikely(!left && bytes)) {
|
|
iov++;
|
|
buf = iov->iov_base;
|
|
copy = min(bytes, iov->iov_len);
|
|
left = __copy_from_user(to, buf, copy);
|
|
copy -= left;
|
|
skip = copy;
|
|
to += copy;
|
|
bytes -= copy;
|
|
}
|
|
kunmap(page);
|
|
done:
|
|
if (skip == iov->iov_len) {
|
|
iov++;
|
|
skip = 0;
|
|
}
|
|
i->count -= wanted - bytes;
|
|
i->nr_segs -= iov - i->iov;
|
|
i->iov = iov;
|
|
i->iov_offset = skip;
|
|
return wanted - bytes;
|
|
}
|
|
|
|
static size_t __iovec_copy_from_user_inatomic(char *vaddr,
|
|
const struct iovec *iov, size_t base, size_t bytes)
|
|
{
|
|
size_t copied = 0, left = 0;
|
|
|
|
while (bytes) {
|
|
char __user *buf = iov->iov_base + base;
|
|
int copy = min(bytes, iov->iov_len - base);
|
|
|
|
base = 0;
|
|
left = __copy_from_user_inatomic(vaddr, buf, copy);
|
|
copied += copy;
|
|
bytes -= copy;
|
|
vaddr += copy;
|
|
iov++;
|
|
|
|
if (unlikely(left))
|
|
break;
|
|
}
|
|
return copied - left;
|
|
}
|
|
|
|
/*
|
|
* Copy as much as we can into the page and return the number of bytes which
|
|
* were successfully copied. If a fault is encountered then return the number of
|
|
* bytes which were copied.
|
|
*/
|
|
static size_t copy_from_user_atomic_iovec(struct page *page,
|
|
struct iov_iter *i, unsigned long offset, size_t bytes)
|
|
{
|
|
char *kaddr;
|
|
size_t copied;
|
|
|
|
kaddr = kmap_atomic(page);
|
|
if (likely(i->nr_segs == 1)) {
|
|
int left;
|
|
char __user *buf = i->iov->iov_base + i->iov_offset;
|
|
left = __copy_from_user_inatomic(kaddr + offset, buf, bytes);
|
|
copied = bytes - left;
|
|
} else {
|
|
copied = __iovec_copy_from_user_inatomic(kaddr + offset,
|
|
i->iov, i->iov_offset, bytes);
|
|
}
|
|
kunmap_atomic(kaddr);
|
|
|
|
return copied;
|
|
}
|
|
|
|
static void advance_iovec(struct iov_iter *i, size_t bytes)
|
|
{
|
|
BUG_ON(i->count < bytes);
|
|
|
|
if (likely(i->nr_segs == 1)) {
|
|
i->iov_offset += bytes;
|
|
i->count -= bytes;
|
|
} else {
|
|
const struct iovec *iov = i->iov;
|
|
size_t base = i->iov_offset;
|
|
unsigned long nr_segs = i->nr_segs;
|
|
|
|
/*
|
|
* The !iov->iov_len check ensures we skip over unlikely
|
|
* zero-length segments (without overruning the iovec).
|
|
*/
|
|
while (bytes || unlikely(i->count && !iov->iov_len)) {
|
|
int copy;
|
|
|
|
copy = min(bytes, iov->iov_len - base);
|
|
BUG_ON(!i->count || i->count < copy);
|
|
i->count -= copy;
|
|
bytes -= copy;
|
|
base += copy;
|
|
if (iov->iov_len == base) {
|
|
iov++;
|
|
nr_segs--;
|
|
base = 0;
|
|
}
|
|
}
|
|
i->iov = iov;
|
|
i->iov_offset = base;
|
|
i->nr_segs = nr_segs;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Fault in the first iovec of the given iov_iter, to a maximum length
|
|
* of bytes. Returns 0 on success, or non-zero if the memory could not be
|
|
* accessed (ie. because it is an invalid address).
|
|
*
|
|
* writev-intensive code may want this to prefault several iovecs -- that
|
|
* would be possible (callers must not rely on the fact that _only_ the
|
|
* first iovec will be faulted with the current implementation).
|
|
*/
|
|
int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes)
|
|
{
|
|
if (!(i->type & ITER_BVEC)) {
|
|
char __user *buf = i->iov->iov_base + i->iov_offset;
|
|
bytes = min(bytes, i->iov->iov_len - i->iov_offset);
|
|
return fault_in_pages_readable(buf, bytes);
|
|
}
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_fault_in_readable);
|
|
|
|
static unsigned long alignment_iovec(const struct iov_iter *i)
|
|
{
|
|
const struct iovec *iov = i->iov;
|
|
unsigned long res;
|
|
size_t size = i->count;
|
|
size_t n;
|
|
|
|
if (!size)
|
|
return 0;
|
|
|
|
res = (unsigned long)iov->iov_base + i->iov_offset;
|
|
n = iov->iov_len - i->iov_offset;
|
|
if (n >= size)
|
|
return res | size;
|
|
size -= n;
|
|
res |= n;
|
|
while (size > (++iov)->iov_len) {
|
|
res |= (unsigned long)iov->iov_base | iov->iov_len;
|
|
size -= iov->iov_len;
|
|
}
|
|
res |= (unsigned long)iov->iov_base | size;
|
|
return res;
|
|
}
|
|
|
|
void iov_iter_init(struct iov_iter *i, int direction,
|
|
const struct iovec *iov, unsigned long nr_segs,
|
|
size_t count)
|
|
{
|
|
/* It will get better. Eventually... */
|
|
if (segment_eq(get_fs(), KERNEL_DS))
|
|
direction |= ITER_KVEC;
|
|
i->type = direction;
|
|
i->iov = iov;
|
|
i->nr_segs = nr_segs;
|
|
i->iov_offset = 0;
|
|
i->count = count;
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_init);
|
|
|
|
static ssize_t get_pages_iovec(struct iov_iter *i,
|
|
struct page **pages, size_t maxsize,
|
|
size_t *start)
|
|
{
|
|
size_t offset = i->iov_offset;
|
|
const struct iovec *iov = i->iov;
|
|
size_t len;
|
|
unsigned long addr;
|
|
int n;
|
|
int res;
|
|
|
|
len = iov->iov_len - offset;
|
|
if (len > i->count)
|
|
len = i->count;
|
|
if (len > maxsize)
|
|
len = maxsize;
|
|
addr = (unsigned long)iov->iov_base + offset;
|
|
len += *start = addr & (PAGE_SIZE - 1);
|
|
addr &= ~(PAGE_SIZE - 1);
|
|
n = (len + PAGE_SIZE - 1) / PAGE_SIZE;
|
|
res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, pages);
|
|
if (unlikely(res < 0))
|
|
return res;
|
|
return (res == n ? len : res * PAGE_SIZE) - *start;
|
|
}
|
|
|
|
static ssize_t get_pages_alloc_iovec(struct iov_iter *i,
|
|
struct page ***pages, size_t maxsize,
|
|
size_t *start)
|
|
{
|
|
size_t offset = i->iov_offset;
|
|
const struct iovec *iov = i->iov;
|
|
size_t len;
|
|
unsigned long addr;
|
|
void *p;
|
|
int n;
|
|
int res;
|
|
|
|
len = iov->iov_len - offset;
|
|
if (len > i->count)
|
|
len = i->count;
|
|
if (len > maxsize)
|
|
len = maxsize;
|
|
addr = (unsigned long)iov->iov_base + offset;
|
|
len += *start = addr & (PAGE_SIZE - 1);
|
|
addr &= ~(PAGE_SIZE - 1);
|
|
n = (len + PAGE_SIZE - 1) / PAGE_SIZE;
|
|
|
|
p = kmalloc(n * sizeof(struct page *), GFP_KERNEL);
|
|
if (!p)
|
|
p = vmalloc(n * sizeof(struct page *));
|
|
if (!p)
|
|
return -ENOMEM;
|
|
|
|
res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p);
|
|
if (unlikely(res < 0)) {
|
|
kvfree(p);
|
|
return res;
|
|
}
|
|
*pages = p;
|
|
return (res == n ? len : res * PAGE_SIZE) - *start;
|
|
}
|
|
|
|
static int iov_iter_npages_iovec(const struct iov_iter *i, int maxpages)
|
|
{
|
|
size_t offset = i->iov_offset;
|
|
size_t size = i->count;
|
|
const struct iovec *iov = i->iov;
|
|
int npages = 0;
|
|
int n;
|
|
|
|
for (n = 0; size && n < i->nr_segs; n++, iov++) {
|
|
unsigned long addr = (unsigned long)iov->iov_base + offset;
|
|
size_t len = iov->iov_len - offset;
|
|
offset = 0;
|
|
if (unlikely(!len)) /* empty segment */
|
|
continue;
|
|
if (len > size)
|
|
len = size;
|
|
npages += (addr + len + PAGE_SIZE - 1) / PAGE_SIZE
|
|
- addr / PAGE_SIZE;
|
|
if (npages >= maxpages) /* don't bother going further */
|
|
return maxpages;
|
|
size -= len;
|
|
offset = 0;
|
|
}
|
|
return min(npages, maxpages);
|
|
}
|
|
|
|
static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t len)
|
|
{
|
|
char *from = kmap_atomic(page);
|
|
memcpy(to, from + offset, len);
|
|
kunmap_atomic(from);
|
|
}
|
|
|
|
static void memcpy_to_page(struct page *page, size_t offset, char *from, size_t len)
|
|
{
|
|
char *to = kmap_atomic(page);
|
|
memcpy(to + offset, from, len);
|
|
kunmap_atomic(to);
|
|
}
|
|
|
|
static size_t copy_page_to_iter_bvec(struct page *page, size_t offset, size_t bytes,
|
|
struct iov_iter *i)
|
|
{
|
|
size_t skip, copy, wanted;
|
|
const struct bio_vec *bvec;
|
|
void *kaddr, *from;
|
|
|
|
if (unlikely(bytes > i->count))
|
|
bytes = i->count;
|
|
|
|
if (unlikely(!bytes))
|
|
return 0;
|
|
|
|
wanted = bytes;
|
|
bvec = i->bvec;
|
|
skip = i->iov_offset;
|
|
copy = min_t(size_t, bytes, bvec->bv_len - skip);
|
|
|
|
kaddr = kmap_atomic(page);
|
|
from = kaddr + offset;
|
|
memcpy_to_page(bvec->bv_page, skip + bvec->bv_offset, from, copy);
|
|
skip += copy;
|
|
from += copy;
|
|
bytes -= copy;
|
|
while (bytes) {
|
|
bvec++;
|
|
copy = min(bytes, (size_t)bvec->bv_len);
|
|
memcpy_to_page(bvec->bv_page, bvec->bv_offset, from, copy);
|
|
skip = copy;
|
|
from += copy;
|
|
bytes -= copy;
|
|
}
|
|
kunmap_atomic(kaddr);
|
|
if (skip == bvec->bv_len) {
|
|
bvec++;
|
|
skip = 0;
|
|
}
|
|
i->count -= wanted - bytes;
|
|
i->nr_segs -= bvec - i->bvec;
|
|
i->bvec = bvec;
|
|
i->iov_offset = skip;
|
|
return wanted - bytes;
|
|
}
|
|
|
|
static size_t copy_page_from_iter_bvec(struct page *page, size_t offset, size_t bytes,
|
|
struct iov_iter *i)
|
|
{
|
|
size_t skip, copy, wanted;
|
|
const struct bio_vec *bvec;
|
|
void *kaddr, *to;
|
|
|
|
if (unlikely(bytes > i->count))
|
|
bytes = i->count;
|
|
|
|
if (unlikely(!bytes))
|
|
return 0;
|
|
|
|
wanted = bytes;
|
|
bvec = i->bvec;
|
|
skip = i->iov_offset;
|
|
|
|
kaddr = kmap_atomic(page);
|
|
|
|
to = kaddr + offset;
|
|
|
|
copy = min(bytes, bvec->bv_len - skip);
|
|
|
|
memcpy_from_page(to, bvec->bv_page, bvec->bv_offset + skip, copy);
|
|
|
|
to += copy;
|
|
skip += copy;
|
|
bytes -= copy;
|
|
|
|
while (bytes) {
|
|
bvec++;
|
|
copy = min(bytes, (size_t)bvec->bv_len);
|
|
memcpy_from_page(to, bvec->bv_page, bvec->bv_offset, copy);
|
|
skip = copy;
|
|
to += copy;
|
|
bytes -= copy;
|
|
}
|
|
kunmap_atomic(kaddr);
|
|
if (skip == bvec->bv_len) {
|
|
bvec++;
|
|
skip = 0;
|
|
}
|
|
i->count -= wanted;
|
|
i->nr_segs -= bvec - i->bvec;
|
|
i->bvec = bvec;
|
|
i->iov_offset = skip;
|
|
return wanted;
|
|
}
|
|
|
|
static size_t copy_from_user_bvec(struct page *page,
|
|
struct iov_iter *i, unsigned long offset, size_t bytes)
|
|
{
|
|
char *kaddr;
|
|
size_t left;
|
|
const struct bio_vec *bvec;
|
|
size_t base = i->iov_offset;
|
|
|
|
kaddr = kmap_atomic(page);
|
|
for (left = bytes, bvec = i->bvec; left; bvec++, base = 0) {
|
|
size_t copy = min(left, bvec->bv_len - base);
|
|
if (!bvec->bv_len)
|
|
continue;
|
|
memcpy_from_page(kaddr + offset, bvec->bv_page,
|
|
bvec->bv_offset + base, copy);
|
|
offset += copy;
|
|
left -= copy;
|
|
}
|
|
kunmap_atomic(kaddr);
|
|
return bytes;
|
|
}
|
|
|
|
static void advance_bvec(struct iov_iter *i, size_t bytes)
|
|
{
|
|
BUG_ON(i->count < bytes);
|
|
|
|
if (likely(i->nr_segs == 1)) {
|
|
i->iov_offset += bytes;
|
|
i->count -= bytes;
|
|
} else {
|
|
const struct bio_vec *bvec = i->bvec;
|
|
size_t base = i->iov_offset;
|
|
unsigned long nr_segs = i->nr_segs;
|
|
|
|
/*
|
|
* The !iov->iov_len check ensures we skip over unlikely
|
|
* zero-length segments (without overruning the iovec).
|
|
*/
|
|
while (bytes || unlikely(i->count && !bvec->bv_len)) {
|
|
int copy;
|
|
|
|
copy = min(bytes, bvec->bv_len - base);
|
|
BUG_ON(!i->count || i->count < copy);
|
|
i->count -= copy;
|
|
bytes -= copy;
|
|
base += copy;
|
|
if (bvec->bv_len == base) {
|
|
bvec++;
|
|
nr_segs--;
|
|
base = 0;
|
|
}
|
|
}
|
|
i->bvec = bvec;
|
|
i->iov_offset = base;
|
|
i->nr_segs = nr_segs;
|
|
}
|
|
}
|
|
|
|
static unsigned long alignment_bvec(const struct iov_iter *i)
|
|
{
|
|
const struct bio_vec *bvec = i->bvec;
|
|
unsigned long res;
|
|
size_t size = i->count;
|
|
size_t n;
|
|
|
|
if (!size)
|
|
return 0;
|
|
|
|
res = bvec->bv_offset + i->iov_offset;
|
|
n = bvec->bv_len - i->iov_offset;
|
|
if (n >= size)
|
|
return res | size;
|
|
size -= n;
|
|
res |= n;
|
|
while (size > (++bvec)->bv_len) {
|
|
res |= bvec->bv_offset | bvec->bv_len;
|
|
size -= bvec->bv_len;
|
|
}
|
|
res |= bvec->bv_offset | size;
|
|
return res;
|
|
}
|
|
|
|
static ssize_t get_pages_bvec(struct iov_iter *i,
|
|
struct page **pages, size_t maxsize,
|
|
size_t *start)
|
|
{
|
|
const struct bio_vec *bvec = i->bvec;
|
|
size_t len = bvec->bv_len - i->iov_offset;
|
|
if (len > i->count)
|
|
len = i->count;
|
|
if (len > maxsize)
|
|
len = maxsize;
|
|
*start = bvec->bv_offset + i->iov_offset;
|
|
|
|
get_page(*pages = bvec->bv_page);
|
|
|
|
return len;
|
|
}
|
|
|
|
static ssize_t get_pages_alloc_bvec(struct iov_iter *i,
|
|
struct page ***pages, size_t maxsize,
|
|
size_t *start)
|
|
{
|
|
const struct bio_vec *bvec = i->bvec;
|
|
size_t len = bvec->bv_len - i->iov_offset;
|
|
if (len > i->count)
|
|
len = i->count;
|
|
if (len > maxsize)
|
|
len = maxsize;
|
|
*start = bvec->bv_offset + i->iov_offset;
|
|
|
|
*pages = kmalloc(sizeof(struct page *), GFP_KERNEL);
|
|
if (!*pages)
|
|
return -ENOMEM;
|
|
|
|
get_page(**pages = bvec->bv_page);
|
|
|
|
return len;
|
|
}
|
|
|
|
static int iov_iter_npages_bvec(const struct iov_iter *i, int maxpages)
|
|
{
|
|
size_t offset = i->iov_offset;
|
|
size_t size = i->count;
|
|
const struct bio_vec *bvec = i->bvec;
|
|
int npages = 0;
|
|
int n;
|
|
|
|
for (n = 0; size && n < i->nr_segs; n++, bvec++) {
|
|
size_t len = bvec->bv_len - offset;
|
|
offset = 0;
|
|
if (unlikely(!len)) /* empty segment */
|
|
continue;
|
|
if (len > size)
|
|
len = size;
|
|
npages++;
|
|
if (npages >= maxpages) /* don't bother going further */
|
|
return maxpages;
|
|
size -= len;
|
|
offset = 0;
|
|
}
|
|
return min(npages, maxpages);
|
|
}
|
|
|
|
size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
|
|
struct iov_iter *i)
|
|
{
|
|
if (i->type & ITER_BVEC)
|
|
return copy_page_to_iter_bvec(page, offset, bytes, i);
|
|
else
|
|
return copy_page_to_iter_iovec(page, offset, bytes, i);
|
|
}
|
|
EXPORT_SYMBOL(copy_page_to_iter);
|
|
|
|
size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
|
|
struct iov_iter *i)
|
|
{
|
|
if (i->type & ITER_BVEC)
|
|
return copy_page_from_iter_bvec(page, offset, bytes, i);
|
|
else
|
|
return copy_page_from_iter_iovec(page, offset, bytes, i);
|
|
}
|
|
EXPORT_SYMBOL(copy_page_from_iter);
|
|
|
|
size_t iov_iter_copy_from_user_atomic(struct page *page,
|
|
struct iov_iter *i, unsigned long offset, size_t bytes)
|
|
{
|
|
if (i->type & ITER_BVEC)
|
|
return copy_from_user_bvec(page, i, offset, bytes);
|
|
else
|
|
return copy_from_user_atomic_iovec(page, i, offset, bytes);
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_copy_from_user_atomic);
|
|
|
|
void iov_iter_advance(struct iov_iter *i, size_t size)
|
|
{
|
|
if (i->type & ITER_BVEC)
|
|
advance_bvec(i, size);
|
|
else
|
|
advance_iovec(i, size);
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_advance);
|
|
|
|
/*
|
|
* Return the count of just the current iov_iter segment.
|
|
*/
|
|
size_t iov_iter_single_seg_count(const struct iov_iter *i)
|
|
{
|
|
if (i->nr_segs == 1)
|
|
return i->count;
|
|
else if (i->type & ITER_BVEC)
|
|
return min(i->count, i->iov->iov_len - i->iov_offset);
|
|
else
|
|
return min(i->count, i->bvec->bv_len - i->iov_offset);
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_single_seg_count);
|
|
|
|
unsigned long iov_iter_alignment(const struct iov_iter *i)
|
|
{
|
|
if (i->type & ITER_BVEC)
|
|
return alignment_bvec(i);
|
|
else
|
|
return alignment_iovec(i);
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_alignment);
|
|
|
|
ssize_t iov_iter_get_pages(struct iov_iter *i,
|
|
struct page **pages, size_t maxsize,
|
|
size_t *start)
|
|
{
|
|
if (i->type & ITER_BVEC)
|
|
return get_pages_bvec(i, pages, maxsize, start);
|
|
else
|
|
return get_pages_iovec(i, pages, maxsize, start);
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_get_pages);
|
|
|
|
ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
|
|
struct page ***pages, size_t maxsize,
|
|
size_t *start)
|
|
{
|
|
if (i->type & ITER_BVEC)
|
|
return get_pages_alloc_bvec(i, pages, maxsize, start);
|
|
else
|
|
return get_pages_alloc_iovec(i, pages, maxsize, start);
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_get_pages_alloc);
|
|
|
|
int iov_iter_npages(const struct iov_iter *i, int maxpages)
|
|
{
|
|
if (i->type & ITER_BVEC)
|
|
return iov_iter_npages_bvec(i, maxpages);
|
|
else
|
|
return iov_iter_npages_iovec(i, maxpages);
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_npages);
|