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Diffstat (limited to 'fs/bio.c')
-rw-r--r--fs/bio.c36
1 files changed, 22 insertions, 14 deletions
diff --git a/fs/bio.c b/fs/bio.c
index 711cee10360..062299acbcc 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -788,6 +788,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
int i, ret;
int nr_pages = 0;
unsigned int len = 0;
+ unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0;
for (i = 0; i < iov_count; i++) {
unsigned long uaddr;
@@ -814,35 +815,42 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
bio->bi_rw |= (!write_to_vm << BIO_RW);
ret = 0;
- i = 0;
+
+ if (map_data) {
+ nr_pages = 1 << map_data->page_order;
+ i = map_data->offset / PAGE_SIZE;
+ }
while (len) {
- unsigned int bytes;
+ unsigned int bytes = PAGE_SIZE;
- if (map_data)
- bytes = 1U << (PAGE_SHIFT + map_data->page_order);
- else
- bytes = PAGE_SIZE;
+ bytes -= offset;
if (bytes > len)
bytes = len;
if (map_data) {
- if (i == map_data->nr_entries) {
+ if (i == map_data->nr_entries * nr_pages) {
ret = -ENOMEM;
break;
}
- page = map_data->pages[i++];
- } else
+
+ page = map_data->pages[i / nr_pages];
+ page += (i % nr_pages);
+
+ i++;
+ } else {
page = alloc_page(q->bounce_gfp | gfp_mask);
- if (!page) {
- ret = -ENOMEM;
- break;
+ if (!page) {
+ ret = -ENOMEM;
+ break;
+ }
}
- if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes)
+ if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
break;
len -= bytes;
+ offset = 0;
}
if (ret)
@@ -851,7 +859,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
/*
* success
*/
- if (!write_to_vm) {
+ if (!write_to_vm && (!map_data || !map_data->null_mapped)) {
ret = __bio_copy_iov(bio, bio->bi_io_vec, iov, iov_count, 0, 0);
if (ret)
goto cleanup;