---
drivers/block/loop.c | 281 ++++++++++++++++++++-------------------------------
1 file changed, 109 insertions(+), 172 deletions(-)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 6cb1beb..3e70116 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -85,28 +85,6 @@ static DEFINE_MUTEX(loop_index_mutex);
static int max_part;
static int part_shift;
-/*
- * Transfer functions
- */
-static int transfer_none(struct loop_device *lo, int cmd,
- struct page *raw_page, unsigned raw_off,
- struct page *loop_page, unsigned loop_off,
- int size, sector_t real_block)
-{
- char *raw_buf = kmap_atomic(raw_page) + raw_off;
- char *loop_buf = kmap_atomic(loop_page) + loop_off;
-
- if (cmd == READ)
- memcpy(loop_buf, raw_buf, size);
- else
- memcpy(raw_buf, loop_buf, size);
-
- kunmap_atomic(loop_buf);
- kunmap_atomic(raw_buf);
- cond_resched();
- return 0;
-}
-
static int transfer_xor(struct loop_device *lo, int cmd,
struct page *raw_page, unsigned raw_off,
struct page *loop_page, unsigned loop_off,
@@ -145,7 +123,6 @@ static int xor_init(struct loop_device *lo, const struct loop_info64 *info)
static struct loop_func_table none_funcs = {
.number = LO_CRYPT_NONE,
- .transfer = transfer_none,
};
static struct loop_func_table xor_funcs = {
@@ -212,203 +189,156 @@ lo_do_transfer(struct loop_device *lo, int cmd,
struct page *lpage, unsigned loffs,
int size, sector_t rblock)
{
- if (unlikely(!lo->transfer))
+ int ret;
+
+ ret = lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock);
+ if (likely(!ret))
return 0;
- return lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock);
+ printk_ratelimited(KERN_ERR
+ "loop: Transfer error at byte offset %llu, length %i.\n",
+ (unsigned long long)rblock << 9, size);
+ return ret;
}
-/**
- * __do_lo_send_write - helper for writing data to a loop device
- *
- * This helper just factors out common code between do_lo_send_direct_write()
- * and do_lo_send_write().
- */
-static int __do_lo_send_write(struct file *file,
- u8 *buf, const int len, loff_t pos)
+static int lo_write_bvec(struct file *file, struct bio_vec *bvec, loff_t *ppos)
{
ssize_t bw;
- mm_segment_t old_fs = get_fs();
file_start_write(file);
- set_fs(get_ds());
- bw = file->f_op->write(file, buf, len, &pos);
- set_fs(old_fs);
+ bw = vfs_bvec_write(file, bvec, 1, bvec->bv_len, ppos);
file_end_write(file);
- if (likely(bw == len))
+
+ if (likely(bw == bvec->bv_len))
return 0;
- printk_ratelimited(KERN_ERR "loop: Write error at byte offset %llu, length %i.\n",
- (unsigned long long)pos, len);
+
+ printk_ratelimited(KERN_ERR
+ "loop: Write error at byte offset %llu, length %i.\n",
+ (unsigned long long)*ppos, bvec->bv_len);
if (bw >= 0)
bw = -EIO;
return bw;
}
-/**
- * do_lo_send_direct_write - helper for writing data to a loop device
- *
- * This is the fast, non-transforming version that does not need double
- * buffering.
- */
-static int do_lo_send_direct_write(struct loop_device *lo,
- struct bio_vec *bvec, loff_t pos, struct page *page)
+static int lo_write_simple(struct loop_device *lo, struct bio *bio, loff_t pos)
{
- ssize_t bw = __do_lo_send_write(lo->lo_backing_file,
- kmap(bvec->bv_page) + bvec->bv_offset,
- bvec->bv_len, pos);
- kunmap(bvec->bv_page);
- cond_resched();
- return bw;
+ struct bio_vec bvec;
+ struct bvec_iter iter;
+ int ret = 0;
+
+ bio_for_each_segment(bvec, bio, iter) {
+ ret = lo_write_bvec(lo->lo_backing_file, &bvec, &pos);
+ if (ret < 0)
+ break;
+ cond_resched();
+ }
+
+ return ret;
}
-/**
- * do_lo_send_write - helper for writing data to a loop device
- *
+/*
* This is the slow, transforming version that needs to double buffer the
* data as it cannot do the transformations in place without having direct
* access to the destination pages of the backing file.
*/
-static int do_lo_send_write(struct loop_device *lo, struct bio_vec *bvec,
- loff_t pos, struct page *page)
+static int lo_write_transfer(struct loop_device *lo, struct bio *bio,
+ loff_t pos)
{
- int ret = lo_do_transfer(lo, WRITE, page, 0, bvec->bv_page,
- bvec->bv_offset, bvec->bv_len, pos >> 9);
- if (likely(!ret))
- return __do_lo_send_write(lo->lo_backing_file,
- page_address(page), bvec->bv_len,
- pos);
- printk_ratelimited(KERN_ERR "loop: Transfer error at byte offset %llu, "
- "length %i.\n", (unsigned long long)pos, bvec->bv_len);
- if (ret > 0)
- ret = -EIO;
- return ret;
-}
-
-static int lo_send(struct loop_device *lo, struct bio *bio, loff_t pos)
-{
- int (*do_lo_send)(struct loop_device *, struct bio_vec *, loff_t,
- struct page *page);
- struct bio_vec bvec;
+ struct bio_vec bvec, b;
struct bvec_iter iter;
- struct page *page = NULL;
+ struct page *page;
int ret = 0;
- if (lo->transfer != transfer_none) {
- page = alloc_page(GFP_NOIO | __GFP_HIGHMEM);
- if (unlikely(!page))
- goto fail;
- kmap(page);
- do_lo_send = do_lo_send_write;
- } else {
- do_lo_send = do_lo_send_direct_write;
- }
+ page = alloc_page(GFP_NOIO);
+ if (unlikely(!page))
+ return -ENOMEM;
bio_for_each_segment(bvec, bio, iter) {
- ret = do_lo_send(lo, &bvec, pos, page);
+ ret = lo_do_transfer(lo, WRITE, page, 0, bvec.bv_page,
+ bvec.bv_offset, bvec.bv_len, pos >> 9);
+ if (unlikely(ret))
+ break;
+
+ b.bv_page = page;
+ b.bv_offset = 0;
+ b.bv_len = bvec.bv_len;
+ ret = lo_write_bvec(lo->lo_backing_file, &b, &pos);
if (ret < 0)
break;
- pos += bvec.bv_len;
}
- if (page) {
- kunmap(page);
- __free_page(page);
- }
-out:
+
+ __free_page(page);
return ret;
-fail:
- printk_ratelimited(KERN_ERR "loop: Failed to allocate temporary page for write.\n");
- ret = -ENOMEM;
- goto out;
}
-struct lo_read_data {
- struct loop_device *lo;
- struct page *page;
- unsigned offset;
- int bsize;
-};
-
-static int
-lo_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
- struct splice_desc *sd)
+static int lo_read_simple(struct loop_device *lo, struct bio *bio, loff_t pos)
{
- struct lo_read_data *p = sd->u.data;
- struct loop_device *lo = p->lo;
- struct page *page = buf->page;
- sector_t IV;
- int size;
-
- IV = ((sector_t) page->index << (PAGE_CACHE_SHIFT - 9)) +
- (buf->offset >> 9);
- size = sd->len;
- if (size > p->bsize)
- size = p->bsize;
-
- if (lo_do_transfer(lo, READ, page, buf->offset, p->page, p->offset, size, IV)) {
- printk_ratelimited(KERN_ERR "loop: transfer error block %ld\n",
- page->index);
- size = -EINVAL;
- }
+ struct bio_vec bvec;
+ struct bvec_iter iter;
+ ssize_t len;
- flush_dcache_page(p->page);
+ bio_for_each_segment(bvec, bio, iter) {
+ len = vfs_bvec_read(lo->lo_backing_file, &bvec, 1, bvec.bv_len,
+ &pos);
+ if (len < 0)
+ return len;
- if (size > 0)
- p->offset += size;
+ flush_dcache_page(bvec.bv_page);
- return size;
-}
+ if (len != bvec.bv_len) {
+ zero_fill_bio(bio);
+ break;
+ }
+ cond_resched();
+ }
-static int
-lo_direct_splice_actor(struct pipe_inode_info *pipe, struct splice_desc *sd)
-{
- return __splice_from_pipe(pipe, sd, lo_splice_actor);
+ return 0;
}
-static ssize_t
-do_lo_receive(struct loop_device *lo,
- struct bio_vec *bvec, int bsize, loff_t pos)
+static int lo_read_transfer(struct loop_device *lo, struct bio *bio,
+ loff_t pos)
{
- struct lo_read_data cookie;
- struct splice_desc sd;
- struct file *file;
- ssize_t retval;
-
- cookie.lo = lo;
- cookie.page = bvec->bv_page;
- cookie.offset = bvec->bv_offset;
- cookie.bsize = bsize;
+ struct bio_vec bvec, b;
+ struct bvec_iter iter;
+ struct page *page;
+ ssize_t len;
+ int ret = 0;
- sd.len = 0;
- sd.total_len = bvec->bv_len;
- sd.flags = 0;
- sd.pos = pos;
- sd.u.data = &cookie;
+ page = alloc_page(GFP_NOIO);
+ if (unlikely(!page))
+ return -ENOMEM;
- file = lo->lo_backing_file;
- retval = splice_direct_to_actor(file, &sd, lo_direct_splice_actor);
+ bio_for_each_segment(bvec, bio, iter) {
+ loff_t offset = pos;
- return retval;
-}
+ b.bv_page = page;
+ b.bv_offset = 0;
+ b.bv_len = bvec.bv_len;
-static int
-lo_receive(struct loop_device *lo, struct bio *bio, int bsize, loff_t pos)
-{
- struct bio_vec bvec;
- struct bvec_iter iter;
- ssize_t s;
+ len = vfs_bvec_read(lo->lo_backing_file, &b, 1, b.bv_len,
+ &pos);
+ if (len < 0) {
+ ret = len;
+ goto out_free_page;
+ }
- bio_for_each_segment(bvec, bio, iter) {
- s = do_lo_receive(lo, &bvec, bsize, pos);
- if (s < 0)
- return s;
+ ret = lo_do_transfer(lo, READ, page, 0, bvec.bv_page,
+ bvec.bv_offset, len, offset >> 9);
+ if (ret)
+ goto out_free_page;
+
+ flush_dcache_page(bvec.bv_page);
- if (s != bvec.bv_len) {
+ if (len != bvec.bv_len) {
zero_fill_bio(bio);
break;
}
- pos += bvec.bv_len;
}
- return 0;
+
+ ret = 0;
+out_free_page:
+ __free_page(page);
+ return ret;
}
static int do_bio_filebacked(struct loop_device *lo, struct bio *bio)
@@ -452,15 +382,22 @@ static int do_bio_filebacked(struct loop_device *lo, struct bio *bio)
goto out;
}
- ret = lo_send(lo, bio, pos);
+ if (lo->transfer)
+ ret = lo_write_transfer(lo, bio, pos);
+ else
+ ret = lo_write_simple(lo, bio, pos);
if ((bio->bi_rw & REQ_FUA) && !ret) {
ret = vfs_fsync(file, 0);
if (unlikely(ret && ret != -EINVAL))
ret = -EIO;
}
- } else
- ret = lo_receive(lo, bio, lo->lo_blocksize, pos);
+ } else {
+ if (lo->transfer)
+ ret = lo_read_transfer(lo, bio, pos);
+ else
+ ret = lo_read_simple(lo, bio, pos);
+ }
out:
return ret;
@@ -886,7 +823,7 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
lo->lo_device = bdev;
lo->lo_flags = lo_flags;
lo->lo_backing_file = file;
- lo->transfer = transfer_none;
+ lo->transfer = NULL;
lo->ioctl = NULL;
lo->lo_sizelimit = 0;
lo->lo_bio_count = 0;
--
1.9.1
--
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