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iov_iter.c: handle ITER_KVEC directly 

... without bothering with copy_..._user()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
wifi-calibration
Al Viro 2014-11-27 14:48:42 -05:00
parent 3d4d3e4826
commit a280455fa8
2 changed files with 70 additions and 13 deletions
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1
include/linux/uio.h
View File

@ -31,6 +31,7 @@ struct iov_iter {
size_t count;
union {
const struct iovec *iov;
const struct kvec *kvec;
const struct bio_vec *bvec;
};
unsigned long nr_segs;

82
mm/iov_iter.c
View File

@ -32,6 +32,29 @@
n = wanted - n; \
}
#define iterate_kvec(i, n, __v, __p, skip, STEP) { \
size_t wanted = n; \
__p = i->kvec; \
__v.iov_len = min(n, __p->iov_len - skip); \
if (likely(__v.iov_len)) { \
__v.iov_base = __p->iov_base + skip; \
(void)(STEP); \
skip += __v.iov_len; \
n -= __v.iov_len; \
} \
while (unlikely(n)) { \
__p++; \
__v.iov_len = min(n, __p->iov_len); \
if (unlikely(!__v.iov_len)) \
continue; \
__v.iov_base = __p->iov_base; \
(void)(STEP); \
skip = __v.iov_len; \
n -= __v.iov_len; \
} \
n = wanted; \
}
#define iterate_bvec(i, n, __v, __p, skip, STEP) { \
size_t wanted = n; \
__p = i->bvec; \
@ -57,12 +80,16 @@
n = wanted; \
}
#define iterate_all_kinds(i, n, v, I, B) { \
#define iterate_all_kinds(i, n, v, I, B, K) { \
size_t skip = i->iov_offset; \
if (unlikely(i->type & ITER_BVEC)) { \
const struct bio_vec *bvec; \
struct bio_vec v; \
iterate_bvec(i, n, v, bvec, skip, (B)) \
} else if (unlikely(i->type & ITER_KVEC)) { \
const struct kvec *kvec; \
struct kvec v; \
iterate_kvec(i, n, v, kvec, skip, (K)) \
} else { \
const struct iovec *iov; \
struct iovec v; \
@ -70,7 +97,7 @@
} \
}
#define iterate_and_advance(i, n, v, I, B) { \
#define iterate_and_advance(i, n, v, I, B, K) { \
size_t skip = i->iov_offset; \
if (unlikely(i->type & ITER_BVEC)) { \
const struct bio_vec *bvec; \
@ -82,6 +109,16 @@
} \
i->nr_segs -= bvec - i->bvec; \
i->bvec = bvec; \
} else if (unlikely(i->type & ITER_KVEC)) { \
const struct kvec *kvec; \
struct kvec v; \
iterate_kvec(i, n, v, kvec, skip, (K)) \
if (skip == kvec->iov_len) { \
kvec++; \
skip = 0; \
} \
i->nr_segs -= kvec - i->kvec; \
i->kvec = kvec; \
} else { \
const struct iovec *iov; \
struct iovec v; \
@ -270,7 +307,7 @@ done:
*/
int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes)
{
if (!(i->type & ITER_BVEC)) {
if (!(i->type & (ITER_BVEC|ITER_KVEC))) {
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);
@ -284,10 +321,14 @@ void iov_iter_init(struct iov_iter *i, int direction,
size_t count)
{
/* It will get better. Eventually... */
if (segment_eq(get_fs(), KERNEL_DS))
if (segment_eq(get_fs(), KERNEL_DS)) {
direction |= ITER_KVEC;
i->type = direction;
i->iov = iov;
i->type = direction;
i->kvec = (struct kvec *)iov;
} else {
i->type = direction;
i->iov = iov;
}
i->nr_segs = nr_segs;
i->iov_offset = 0;
i->count = count;
@ -328,7 +369,8 @@ size_t copy_to_iter(void *addr, size_t bytes, struct iov_iter *i)
__copy_to_user(v.iov_base, (from += v.iov_len) - v.iov_len,
v.iov_len),
memcpy_to_page(v.bv_page, v.bv_offset,
(from += v.bv_len) - v.bv_len, v.bv_len)
(from += v.bv_len) - v.bv_len, v.bv_len),
memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len)
)
return bytes;
@ -348,7 +390,8 @@ size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
__copy_from_user((to += v.iov_len) - v.iov_len, v.iov_base,
v.iov_len),
memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
v.bv_offset, v.bv_len)
v.bv_offset, v.bv_len),
memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
)
return bytes;
@ -371,7 +414,7 @@ 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) {
if (i->type & (ITER_BVEC|ITER_KVEC)) {
void *kaddr = kmap_atomic(page);
size_t wanted = copy_from_iter(kaddr + offset, bytes, i);
kunmap_atomic(kaddr);
@ -391,7 +434,8 @@ size_t iov_iter_zero(size_t bytes, struct iov_iter *i)
iterate_and_advance(i, bytes, v,
__clear_user(v.iov_base, v.iov_len),
memzero_page(v.bv_page, v.bv_offset, v.bv_len)
memzero_page(v.bv_page, v.bv_offset, v.bv_len),
memset(v.iov_base, 0, v.iov_len)
)
return bytes;
@ -406,7 +450,8 @@ size_t iov_iter_copy_from_user_atomic(struct page *page,
__copy_from_user_inatomic((p += v.iov_len) - v.iov_len,
v.iov_base, v.iov_len),
memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page,
v.bv_offset, v.bv_len)
v.bv_offset, v.bv_len),
memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
)
kunmap_atomic(kaddr);
return bytes;
@ -415,7 +460,7 @@ EXPORT_SYMBOL(iov_iter_copy_from_user_atomic);
void iov_iter_advance(struct iov_iter *i, size_t size)
{
iterate_and_advance(i, size, v, 0, 0)
iterate_and_advance(i, size, v, 0, 0, 0)
}
EXPORT_SYMBOL(iov_iter_advance);
@ -443,7 +488,8 @@ unsigned long iov_iter_alignment(const struct iov_iter *i)
iterate_all_kinds(i, size, v,
(res |= (unsigned long)v.iov_base | v.iov_len, 0),
res |= v.bv_offset | v.bv_len
res |= v.bv_offset | v.bv_len,
res |= (unsigned long)v.iov_base | v.iov_len
)
return res;
}
@ -478,6 +524,8 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
*start = v.bv_offset;
get_page(*pages = v.bv_page);
return v.bv_len;
}),({
return -EFAULT;
})
)
return 0;
@ -530,6 +578,8 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
return -ENOMEM;
get_page(*p = v.bv_page);
return v.bv_len;
}),({
return -EFAULT;
})
)
return 0;
@ -554,6 +604,12 @@ int iov_iter_npages(const struct iov_iter *i, int maxpages)
npages++;
if (npages >= maxpages)
return maxpages;
}),({
unsigned long p = (unsigned long)v.iov_base;
npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE)
- p / PAGE_SIZE;
if (npages >= maxpages)
return maxpages;
})
)
return npages;