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-rw-r--r--mm/iov_iter.c212
1 files changed, 86 insertions, 126 deletions
diff --git a/mm/iov_iter.c b/mm/iov_iter.c
index e34a3cb6aad6..798fcb4294e7 100644
--- a/mm/iov_iter.c
+++ b/mm/iov_iter.c
@@ -4,6 +4,72 @@
#include <linux/slab.h>
#include <linux/vmalloc.h>
+#define iterate_iovec(i, n, __v, __p, skip, STEP) { \
+ size_t left; \
+ size_t wanted = n; \
+ __p = i->iov; \
+ __v.iov_len = min(n, __p->iov_len - skip); \
+ if (likely(__v.iov_len)) { \
+ __v.iov_base = __p->iov_base + skip; \
+ left = (STEP); \
+ __v.iov_len -= left; \
+ skip += __v.iov_len; \
+ n -= __v.iov_len; \
+ } else { \
+ left = 0; \
+ } \
+ while (unlikely(!left && n)) { \
+ __p++; \
+ __v.iov_len = min(n, __p->iov_len); \
+ if (unlikely(!__v.iov_len)) \
+ continue; \
+ __v.iov_base = __p->iov_base; \
+ left = (STEP); \
+ __v.iov_len -= left; \
+ skip = __v.iov_len; \
+ n -= __v.iov_len; \
+ } \
+ n = wanted - n; \
+}
+
+#define iterate_bvec(i, n, __v, __p, skip, STEP) { \
+ size_t wanted = n; \
+ __p = i->bvec; \
+ __v.bv_len = min_t(size_t, n, __p->bv_len - skip); \
+ if (likely(__v.bv_len)) { \
+ __v.bv_page = __p->bv_page; \
+ __v.bv_offset = __p->bv_offset + skip; \
+ (void)(STEP); \
+ skip += __v.bv_len; \
+ n -= __v.bv_len; \
+ } \
+ while (unlikely(n)) { \
+ __p++; \
+ __v.bv_len = min_t(size_t, n, __p->bv_len); \
+ if (unlikely(!__v.bv_len)) \
+ continue; \
+ __v.bv_page = __p->bv_page; \
+ __v.bv_offset = __p->bv_offset; \
+ (void)(STEP); \
+ skip = __v.bv_len; \
+ n -= __v.bv_len; \
+ } \
+ n = wanted; \
+}
+
+#define iterate_all_kinds(i, n, v, I, B) { \
+ 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 { \
+ const struct iovec *iov; \
+ struct iovec v; \
+ iterate_iovec(i, n, v, iov, skip, (I)) \
+ } \
+}
+
static size_t copy_to_iter_iovec(void *from, size_t bytes, struct iov_iter *i)
{
size_t skip, copy, left, wanted;
@@ -300,54 +366,6 @@ static size_t zero_iovec(size_t bytes, struct iov_iter *i)
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);
@@ -404,30 +422,6 @@ int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes)
}
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)
@@ -691,28 +685,6 @@ static size_t zero_bvec(size_t bytes, struct iov_iter *i)
return wanted - bytes;
}
-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);
@@ -749,30 +721,6 @@ static void advance_bvec(struct iov_iter *i, size_t bytes)
}
}
-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, unsigned maxpages,
size_t *start)
@@ -887,10 +835,15 @@ EXPORT_SYMBOL(iov_iter_zero);
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);
+ char *kaddr = kmap_atomic(page), *p = kaddr + offset;
+ iterate_all_kinds(i, bytes, v,
+ __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)
+ )
+ kunmap_atomic(kaddr);
+ return bytes;
}
EXPORT_SYMBOL(iov_iter_copy_from_user_atomic);
@@ -919,10 +872,17 @@ 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);
+ unsigned long res = 0;
+ size_t size = i->count;
+
+ if (!size)
+ return 0;
+
+ iterate_all_kinds(i, size, v,
+ (res |= (unsigned long)v.iov_base | v.iov_len, 0),
+ res |= v.bv_offset | v.bv_len
+ )
+ return res;
}
EXPORT_SYMBOL(iov_iter_alignment);
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-20 23:48:03 +0100