block: loop: switch to VFS ITER_BVEC
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index c4fd1e4..ae3fcb4 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -88,28 +88,6 @@
static struct workqueue_struct *loop_wq;
-/*
- * 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,
@@ -148,14 +126,13 @@
static struct loop_func_table none_funcs = {
.number = LO_CRYPT_NONE,
- .transfer = transfer_none,
-};
+};
static struct loop_func_table xor_funcs = {
.number = LO_CRYPT_XOR,
.transfer = transfer_xor,
.init = xor_init
-};
+};
/* xfer_funcs[0] is special - its release function is never called */
static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = {
@@ -215,209 +192,171 @@
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)
{
- struct kvec kvec = {.iov_base = buf, .iov_len = len};
- struct iov_iter from;
+ struct iov_iter i;
ssize_t bw;
- iov_iter_kvec(&from, ITER_KVEC | WRITE, &kvec, 1, len);
+ iov_iter_bvec(&i, ITER_BVEC, bvec, 1, bvec->bv_len);
file_start_write(file);
- bw = vfs_iter_write(file, &from, &pos);
+ bw = vfs_iter_write(file, &i, 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 request *rq,
+ 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 req_iterator iter;
+ int ret = 0;
+
+ rq_for_each_segment(bvec, rq, 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 request *rq,
+ 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 request *rq, 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 req_iterator 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;
rq_for_each_segment(bvec, rq, 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)
-{
- 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;
- }
-
- flush_dcache_page(p->page);
-
- if (size > 0)
- p->offset += size;
-
- return size;
-}
-
-static int
-lo_direct_splice_actor(struct pipe_inode_info *pipe, struct splice_desc *sd)
-{
- return __splice_from_pipe(pipe, sd, lo_splice_actor);
-}
-
-static ssize_t
-do_lo_receive(struct loop_device *lo,
- struct bio_vec *bvec, int bsize, 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;
-
- sd.len = 0;
- sd.total_len = bvec->bv_len;
- sd.flags = 0;
- sd.pos = pos;
- sd.u.data = &cookie;
-
- file = lo->lo_backing_file;
- retval = splice_direct_to_actor(file, &sd, lo_direct_splice_actor);
-
- return retval;
-}
-
-static int
-lo_receive(struct loop_device *lo, struct request *rq, int bsize, loff_t pos)
+static int lo_read_simple(struct loop_device *lo, struct request *rq,
+ loff_t pos)
{
struct bio_vec bvec;
struct req_iterator iter;
- ssize_t s;
+ struct iov_iter i;
+ ssize_t len;
rq_for_each_segment(bvec, rq, iter) {
- s = do_lo_receive(lo, &bvec, bsize, pos);
- if (s < 0)
- return s;
+ iov_iter_bvec(&i, ITER_BVEC, &bvec, 1, bvec.bv_len);
+ len = vfs_iter_read(lo->lo_backing_file, &i, &pos);
+ if (len < 0)
+ return len;
- if (s != bvec.bv_len) {
+ flush_dcache_page(bvec.bv_page);
+
+ if (len != bvec.bv_len) {
struct bio *bio;
__rq_for_each_bio(bio, rq)
zero_fill_bio(bio);
break;
}
- pos += bvec.bv_len;
+ cond_resched();
}
+
return 0;
}
+static int lo_read_transfer(struct loop_device *lo, struct request *rq,
+ loff_t pos)
+{
+ struct bio_vec bvec, b;
+ struct req_iterator iter;
+ struct iov_iter i;
+ struct page *page;
+ ssize_t len;
+ int ret = 0;
+
+ page = alloc_page(GFP_NOIO);
+ if (unlikely(!page))
+ return -ENOMEM;
+
+ rq_for_each_segment(bvec, rq, iter) {
+ loff_t offset = pos;
+
+ b.bv_page = page;
+ b.bv_offset = 0;
+ b.bv_len = bvec.bv_len;
+
+ iov_iter_bvec(&i, ITER_BVEC, &b, 1, b.bv_len);
+ len = vfs_iter_read(lo->lo_backing_file, &i, &pos);
+ if (len < 0) {
+ ret = len;
+ goto out_free_page;
+ }
+
+ 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 (len != bvec.bv_len) {
+ struct bio *bio;
+
+ __rq_for_each_bio(bio, rq)
+ zero_fill_bio(bio);
+ break;
+ }
+ }
+
+ ret = 0;
+out_free_page:
+ __free_page(page);
+ return ret;
+}
+
static int lo_discard(struct loop_device *lo, struct request *rq, loff_t pos)
{
/*
@@ -464,10 +403,17 @@
ret = lo_req_flush(lo, rq);
else if (rq->cmd_flags & REQ_DISCARD)
ret = lo_discard(lo, rq, pos);
+ else if (lo->transfer)
+ ret = lo_write_transfer(lo, rq, pos);
else
- ret = lo_send(lo, rq, pos);
- } else
- ret = lo_receive(lo, rq, lo->lo_blocksize, pos);
+ ret = lo_write_simple(lo, rq, pos);
+
+ } else {
+ if (lo->transfer)
+ ret = lo_read_transfer(lo, rq, pos);
+ else
+ ret = lo_read_simple(lo, rq, pos);
+ }
return ret;
}
@@ -788,7 +734,7 @@
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->old_gfp_mask = mapping_gfp_mask(mapping);
@@ -1007,7 +953,7 @@
memcpy(lo->lo_encrypt_key, info->lo_encrypt_key,
info->lo_encrypt_key_size);
lo->lo_key_owner = uid;
- }
+ }
return 0;
}