block: pass iov_iter to the BLOCK_PC mapping functions
Make use of a new interface provided by iov_iter, backed by
scatter-gather list of iovec, instead of the old interface based on
sg_iovec. Also use iov_iter_advance() instead of manual iteration.
This commit should contain only literal replacements, without
functional changes.
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Doug Gilbert <dgilbert@interlog.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Signed-off-by: Kent Overstreet <kmo@daterainc.com>
[dpark: add more description in commit message]
Signed-off-by: Dongsu Park <dongsu.park@profitbricks.com>
[hch: fixed to do a deep clone of the iov_iter, and to properly use
the iov_iter direction]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/bio.c b/block/bio.c
index 0895f69..7d8c655 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -28,7 +28,6 @@
#include <linux/mempool.h>
#include <linux/workqueue.h>
#include <linux/cgroup.h>
-#include <scsi/sg.h> /* for struct sg_iovec */
#include <trace/events/block.h>
@@ -1022,21 +1021,11 @@
EXPORT_SYMBOL(bio_copy_data);
struct bio_map_data {
- int nr_sgvecs;
int is_our_pages;
- struct sg_iovec sgvecs[];
+ struct iov_iter iter;
+ struct iovec iov[];
};
-static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio,
- const struct sg_iovec *iov, int iov_count,
- int is_our_pages)
-{
- memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count);
- bmd->nr_sgvecs = iov_count;
- bmd->is_our_pages = is_our_pages;
- bio->bi_private = bmd;
-}
-
static struct bio_map_data *bio_alloc_map_data(unsigned int iov_count,
gfp_t gfp_mask)
{
@@ -1044,36 +1033,33 @@
return NULL;
return kmalloc(sizeof(struct bio_map_data) +
- sizeof(struct sg_iovec) * iov_count, gfp_mask);
+ sizeof(struct iovec) * iov_count, gfp_mask);
}
-static int __bio_copy_iov(struct bio *bio, const struct sg_iovec *iov, int iov_count,
- int to_user, int from_user)
+static int __bio_copy_iov(struct bio *bio, const struct iov_iter *iter,
+ int to_user, int from_user)
{
int ret = 0, i;
struct bio_vec *bvec;
- int iov_idx = 0;
- unsigned int iov_off = 0;
+ struct iov_iter iov_iter = *iter;
bio_for_each_segment_all(bvec, bio, i) {
char *bv_addr = page_address(bvec->bv_page);
unsigned int bv_len = bvec->bv_len;
- while (bv_len && iov_idx < iov_count) {
- unsigned int bytes;
- char __user *iov_addr;
-
- bytes = min_t(unsigned int,
- iov[iov_idx].iov_len - iov_off, bv_len);
- iov_addr = iov[iov_idx].iov_base + iov_off;
+ while (bv_len && iov_iter.count) {
+ struct iovec iov = iov_iter_iovec(&iov_iter);
+ unsigned int bytes = min_t(unsigned int, bv_len,
+ iov.iov_len);
if (!ret) {
if (to_user)
- ret = copy_to_user(iov_addr, bv_addr,
- bytes);
+ ret = copy_to_user(iov.iov_base,
+ bv_addr, bytes);
if (from_user)
- ret = copy_from_user(bv_addr, iov_addr,
+ ret = copy_from_user(bv_addr,
+ iov.iov_base,
bytes);
if (ret)
@@ -1082,13 +1068,7 @@
bv_len -= bytes;
bv_addr += bytes;
- iov_addr += bytes;
- iov_off += bytes;
-
- if (iov[iov_idx].iov_len == iov_off) {
- iov_idx++;
- iov_off = 0;
- }
+ iov_iter_advance(&iov_iter, bytes);
}
}
@@ -1122,7 +1102,7 @@
* don't copy into a random user address space, just free.
*/
if (current->mm)
- ret = __bio_copy_iov(bio, bmd->sgvecs, bmd->nr_sgvecs,
+ ret = __bio_copy_iov(bio, &bmd->iter,
bio_data_dir(bio) == READ, 0);
if (bmd->is_our_pages)
bio_free_pages(bio);
@@ -1135,12 +1115,10 @@
/**
* bio_copy_user_iov - copy user data to bio
- * @q: destination block queue
- * @map_data: pointer to the rq_map_data holding pages (if necessary)
- * @iov: the iovec.
- * @iov_count: number of elements in the iovec
- * @write_to_vm: bool indicating writing to pages or not
- * @gfp_mask: memory allocation flags
+ * @q: destination block queue
+ * @map_data: pointer to the rq_map_data holding pages (if necessary)
+ * @iter: iovec iterator
+ * @gfp_mask: memory allocation flags
*
* Prepares and returns a bio for indirect user io, bouncing data
* to/from kernel pages as necessary. Must be paired with
@@ -1148,24 +1126,25 @@
*/
struct bio *bio_copy_user_iov(struct request_queue *q,
struct rq_map_data *map_data,
- const struct sg_iovec *iov, int iov_count,
- int write_to_vm, gfp_t gfp_mask)
+ const struct iov_iter *iter,
+ gfp_t gfp_mask)
{
struct bio_map_data *bmd;
struct page *page;
struct bio *bio;
int i, ret;
int nr_pages = 0;
- unsigned int len = 0;
+ unsigned int len = iter->count;
unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0;
- for (i = 0; i < iov_count; i++) {
+ for (i = 0; i < iter->nr_segs; i++) {
unsigned long uaddr;
unsigned long end;
unsigned long start;
- uaddr = (unsigned long)iov[i].iov_base;
- end = (uaddr + iov[i].iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ uaddr = (unsigned long) iter->iov[i].iov_base;
+ end = (uaddr + iter->iov[i].iov_len + PAGE_SIZE - 1)
+ >> PAGE_SHIFT;
start = uaddr >> PAGE_SHIFT;
/*
@@ -1175,22 +1154,31 @@
return ERR_PTR(-EINVAL);
nr_pages += end - start;
- len += iov[i].iov_len;
}
if (offset)
nr_pages++;
- bmd = bio_alloc_map_data(iov_count, gfp_mask);
+ bmd = bio_alloc_map_data(iter->nr_segs, gfp_mask);
if (!bmd)
return ERR_PTR(-ENOMEM);
+ /*
+ * We need to do a deep copy of the iov_iter including the iovecs.
+ * The caller provided iov might point to an on-stack or otherwise
+ * shortlived one.
+ */
+ bmd->is_our_pages = map_data ? 0 : 1;
+ memcpy(bmd->iov, iter->iov, sizeof(struct iovec) * iter->nr_segs);
+ iov_iter_init(&bmd->iter, iter->type, bmd->iov,
+ iter->nr_segs, iter->count);
+
ret = -ENOMEM;
bio = bio_kmalloc(gfp_mask, nr_pages);
if (!bio)
goto out_bmd;
- if (!write_to_vm)
+ if (iter->type & WRITE)
bio->bi_rw |= REQ_WRITE;
ret = 0;
@@ -1238,14 +1226,14 @@
/*
* success
*/
- if ((!write_to_vm && (!map_data || !map_data->null_mapped)) ||
+ if (((iter->type & WRITE) && (!map_data || !map_data->null_mapped)) ||
(map_data && map_data->from_user)) {
- ret = __bio_copy_iov(bio, iov, iov_count, 0, 1);
+ ret = __bio_copy_iov(bio, iter, 0, 1);
if (ret)
goto cleanup;
}
- bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1);
+ bio->bi_private = bmd;
return bio;
cleanup:
if (!map_data)
@@ -1258,19 +1246,21 @@
static struct bio *__bio_map_user_iov(struct request_queue *q,
struct block_device *bdev,
- const struct sg_iovec *iov, int iov_count,
- int write_to_vm, gfp_t gfp_mask)
+ const struct iov_iter *iter,
+ gfp_t gfp_mask)
{
- int i, j;
+ int j;
int nr_pages = 0;
struct page **pages;
struct bio *bio;
int cur_page = 0;
int ret, offset;
+ struct iov_iter i;
+ struct iovec iov;
- for (i = 0; i < iov_count; i++) {
- unsigned long uaddr = (unsigned long)iov[i].iov_base;
- unsigned long len = iov[i].iov_len;
+ iov_for_each(iov, i, *iter) {
+ unsigned long uaddr = (unsigned long) iov.iov_base;
+ unsigned long len = iov.iov_len;
unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
unsigned long start = uaddr >> PAGE_SHIFT;
@@ -1300,16 +1290,17 @@
if (!pages)
goto out;
- for (i = 0; i < iov_count; i++) {
- unsigned long uaddr = (unsigned long)iov[i].iov_base;
- unsigned long len = iov[i].iov_len;
+ iov_for_each(iov, i, *iter) {
+ unsigned long uaddr = (unsigned long) iov.iov_base;
+ unsigned long len = iov.iov_len;
unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
unsigned long start = uaddr >> PAGE_SHIFT;
const int local_nr_pages = end - start;
const int page_limit = cur_page + local_nr_pages;
ret = get_user_pages_fast(uaddr, local_nr_pages,
- write_to_vm, &pages[cur_page]);
+ (iter->type & WRITE) != WRITE,
+ &pages[cur_page]);
if (ret < local_nr_pages) {
ret = -EFAULT;
goto out_unmap;
@@ -1349,7 +1340,7 @@
/*
* set data direction, and check if mapped pages need bouncing
*/
- if (!write_to_vm)
+ if (iter->type & WRITE)
bio->bi_rw |= REQ_WRITE;
bio->bi_bdev = bdev;
@@ -1357,10 +1348,10 @@
return bio;
out_unmap:
- for (i = 0; i < nr_pages; i++) {
- if(!pages[i])
+ for (j = 0; j < nr_pages; j++) {
+ if (!pages[j])
break;
- page_cache_release(pages[i]);
+ page_cache_release(pages[j]);
}
out:
kfree(pages);
@@ -1369,25 +1360,22 @@
}
/**
- * bio_map_user_iov - map user sg_iovec table into bio
- * @q: the struct request_queue for the bio
- * @bdev: destination block device
- * @iov: the iovec.
- * @iov_count: number of elements in the iovec
- * @write_to_vm: bool indicating writing to pages or not
- * @gfp_mask: memory allocation flags
+ * bio_map_user_iov - map user iovec into bio
+ * @q: the struct request_queue for the bio
+ * @bdev: destination block device
+ * @iter: iovec iterator
+ * @gfp_mask: memory allocation flags
*
* Map the user space address into a bio suitable for io to a block
* device. Returns an error pointer in case of error.
*/
struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev,
- const struct sg_iovec *iov, int iov_count,
- int write_to_vm, gfp_t gfp_mask)
+ const struct iov_iter *iter,
+ gfp_t gfp_mask)
{
struct bio *bio;
- bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm,
- gfp_mask);
+ bio = __bio_map_user_iov(q, bdev, iter, gfp_mask);
if (IS_ERR(bio))
return bio;
