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-rw-r--r--include/linux/bvec.h134
1 files changed, 90 insertions, 44 deletions
diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index 02c73c6aa805..a032f01e928c 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -1,21 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0 */
/*
* bvec iterator
*
* Copyright (C) 2001 Ming Lei <ming.lei@canonical.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- *
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public Licens
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
*/
#ifndef __LINUX_BVEC_ITER_H
#define __LINUX_BVEC_ITER_H
@@ -23,6 +10,7 @@
#include <linux/kernel.h>
#include <linux/bug.h>
#include <linux/errno.h>
+#include <linux/mm.h>
/*
* was unsigned short, but we might as well be ready for > 64kB I/O pages
@@ -44,22 +32,51 @@ struct bvec_iter {
current bvec */
};
+struct bvec_iter_all {
+ struct bio_vec bv;
+ int idx;
+ unsigned done;
+};
+
/*
* various member access, note that bio_data should of course not be used
* on highmem page vectors
*/
#define __bvec_iter_bvec(bvec, iter) (&(bvec)[(iter).bi_idx])
-#define bvec_iter_page(bvec, iter) \
+/* multi-page (mp_bvec) helpers */
+#define mp_bvec_iter_page(bvec, iter) \
(__bvec_iter_bvec((bvec), (iter))->bv_page)
-#define bvec_iter_len(bvec, iter) \
+#define mp_bvec_iter_len(bvec, iter) \
min((iter).bi_size, \
__bvec_iter_bvec((bvec), (iter))->bv_len - (iter).bi_bvec_done)
-#define bvec_iter_offset(bvec, iter) \
+#define mp_bvec_iter_offset(bvec, iter) \
(__bvec_iter_bvec((bvec), (iter))->bv_offset + (iter).bi_bvec_done)
+#define mp_bvec_iter_page_idx(bvec, iter) \
+ (mp_bvec_iter_offset((bvec), (iter)) / PAGE_SIZE)
+
+#define mp_bvec_iter_bvec(bvec, iter) \
+((struct bio_vec) { \
+ .bv_page = mp_bvec_iter_page((bvec), (iter)), \
+ .bv_len = mp_bvec_iter_len((bvec), (iter)), \
+ .bv_offset = mp_bvec_iter_offset((bvec), (iter)), \
+})
+
+/* For building single-page bvec in flight */
+ #define bvec_iter_offset(bvec, iter) \
+ (mp_bvec_iter_offset((bvec), (iter)) % PAGE_SIZE)
+
+#define bvec_iter_len(bvec, iter) \
+ min_t(unsigned, mp_bvec_iter_len((bvec), (iter)), \
+ PAGE_SIZE - bvec_iter_offset((bvec), (iter)))
+
+#define bvec_iter_page(bvec, iter) \
+ (mp_bvec_iter_page((bvec), (iter)) + \
+ mp_bvec_iter_page_idx((bvec), (iter)))
+
#define bvec_iter_bvec(bvec, iter) \
((struct bio_vec) { \
.bv_page = bvec_iter_page((bvec), (iter)), \
@@ -77,14 +94,15 @@ static inline bool bvec_iter_advance(const struct bio_vec *bv,
}
while (bytes) {
- unsigned iter_len = bvec_iter_len(bv, *iter);
- unsigned len = min(bytes, iter_len);
+ const struct bio_vec *cur = bv + iter->bi_idx;
+ unsigned len = min3(bytes, iter->bi_size,
+ cur->bv_len - iter->bi_bvec_done);
bytes -= len;
iter->bi_size -= len;
iter->bi_bvec_done += len;
- if (iter->bi_bvec_done == __bvec_iter_bvec(bv, *iter)->bv_len) {
+ if (iter->bi_bvec_done == cur->bv_len) {
iter->bi_bvec_done = 0;
iter->bi_idx++;
}
@@ -92,30 +110,6 @@ static inline bool bvec_iter_advance(const struct bio_vec *bv,
return true;
}
-static inline bool bvec_iter_rewind(const struct bio_vec *bv,
- struct bvec_iter *iter,
- unsigned int bytes)
-{
- while (bytes) {
- unsigned len = min(bytes, iter->bi_bvec_done);
-
- if (iter->bi_bvec_done == 0) {
- if (WARN_ONCE(iter->bi_idx == 0,
- "Attempted to rewind iter beyond "
- "bvec's boundaries\n")) {
- return false;
- }
- iter->bi_idx--;
- iter->bi_bvec_done = __bvec_iter_bvec(bv, *iter)->bv_len;
- continue;
- }
- bytes -= len;
- iter->bi_size += len;
- iter->bi_bvec_done -= len;
- }
- return true;
-}
-
#define for_each_bvec(bvl, bio_vec, iter, start) \
for (iter = (start); \
(iter).bi_size && \
@@ -131,4 +125,56 @@ static inline bool bvec_iter_rewind(const struct bio_vec *bv,
.bi_bvec_done = 0, \
}
+static inline struct bio_vec *bvec_init_iter_all(struct bvec_iter_all *iter_all)
+{
+ iter_all->done = 0;
+ iter_all->idx = 0;
+
+ return &iter_all->bv;
+}
+
+static inline void bvec_advance(const struct bio_vec *bvec,
+ struct bvec_iter_all *iter_all)
+{
+ struct bio_vec *bv = &iter_all->bv;
+
+ if (iter_all->done) {
+ bv->bv_page++;
+ bv->bv_offset = 0;
+ } else {
+ bv->bv_page = bvec->bv_page + (bvec->bv_offset >> PAGE_SHIFT);
+ bv->bv_offset = bvec->bv_offset & ~PAGE_MASK;
+ }
+ bv->bv_len = min_t(unsigned int, PAGE_SIZE - bv->bv_offset,
+ bvec->bv_len - iter_all->done);
+ iter_all->done += bv->bv_len;
+
+ if (iter_all->done == bvec->bv_len) {
+ iter_all->idx++;
+ iter_all->done = 0;
+ }
+}
+
+/*
+ * Get the last single-page segment from the multi-page bvec and store it
+ * in @seg
+ */
+static inline void mp_bvec_last_segment(const struct bio_vec *bvec,
+ struct bio_vec *seg)
+{
+ unsigned total = bvec->bv_offset + bvec->bv_len;
+ unsigned last_page = (total - 1) / PAGE_SIZE;
+
+ seg->bv_page = bvec->bv_page + last_page;
+
+ /* the whole segment is inside the last page */
+ if (bvec->bv_offset >= last_page * PAGE_SIZE) {
+ seg->bv_offset = bvec->bv_offset % PAGE_SIZE;
+ seg->bv_len = bvec->bv_len;
+ } else {
+ seg->bv_offset = 0;
+ seg->bv_len = total - last_page * PAGE_SIZE;
+ }
+}
+
#endif /* __LINUX_BVEC_ITER_H */
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