This patch enables bio_copy_user to take struct sg_iovec (renamed
bio_copy_user_iov). bio_copy_user uses bio_copy_user_iov internally as
bio_map_user uses bio_map_user_iov.
The major changes are:
- adds sg_iovec array to struct bio_map_data
- adds __bio_copy_iov that copy data between bio and
sg_iovec. bio_copy_user_iov and bio_uncopy_user use it.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
Cc: Tejun Heo <htejun@xxxxxxxxx>
Cc: Mike Christie <michaelc@xxxxxxxxxxx>
Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Cc: Jens Axboe <jens.axboe@xxxxxxxxxx>
---
fs/bio.c | 158 +++++++++++++++++++++++++++++++++++++-------------
include/linux/bio.h | 2 +
2 files changed, 119 insertions(+), 41 deletions(-)
diff --git a/fs/bio.c b/fs/bio.c
index 553b5b7..6e0b6f6 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -444,22 +444,27 @@ int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
struct bio_map_data {
struct bio_vec *iovecs;
- void __user *userptr;
+ int nr_sgvecs;
+ struct sg_iovec *sgvecs;
};
-static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio)
+static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio,
+ struct sg_iovec *iov, int iov_count)
{
memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
+ memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count);
+ bmd->nr_sgvecs = iov_count;
bio->bi_private = bmd;
}
static void bio_free_map_data(struct bio_map_data *bmd)
{
kfree(bmd->iovecs);
+ kfree(bmd->sgvecs);
kfree(bmd);
}
-static struct bio_map_data *bio_alloc_map_data(int nr_segs)
+static struct bio_map_data *bio_alloc_map_data(int nr_segs, int iov_count)
{
struct bio_map_data *bmd = kmalloc(sizeof(*bmd), GFP_KERNEL);
@@ -467,13 +472,71 @@ static struct bio_map_data *bio_alloc_map_data(int nr_segs)
return NULL;
bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, GFP_KERNEL);
- if (bmd->iovecs)
+ if (!bmd->iovecs) {
+ kfree(bmd);
+ return NULL;
+ }
+
+ bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, GFP_KERNEL);
+ if (bmd->sgvecs)
return bmd;
+ kfree(bmd->iovecs);
kfree(bmd);
return NULL;
}
+static int __bio_copy_iov(struct bio *bio, struct sg_iovec *iov, int iov_count,
+ int uncopy)
+{
+ int ret = 0, i;
+ struct bio_vec *bvec;
+ int iov_idx = 0;
+ unsigned int iov_off = 0;
+ int read = bio_data_dir(bio) == READ;
+
+ __bio_for_each_segment(bvec, bio, i, 0) {
+ 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 *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;
+
+ if (!ret) {
+ if (!read && !uncopy)
+ ret = copy_from_user(bv_addr, iov_addr,
+ bytes);
+ if (read && uncopy)
+ ret = copy_to_user(iov_addr, bv_addr,
+ bytes);
+
+ if (ret)
+ ret = -EFAULT;
+ }
+
+ 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;
+ }
+ }
+
+ if (uncopy)
+ __free_page(bvec->bv_page);
+ }
+
+ return ret;
+}
+
/**
* bio_uncopy_user - finish previously mapped bio
* @bio: bio being terminated
@@ -484,55 +547,56 @@ static struct bio_map_data *bio_alloc_map_data(int nr_segs)
int bio_uncopy_user(struct bio *bio)
{
struct bio_map_data *bmd = bio->bi_private;
- const int read = bio_data_dir(bio) == READ;
- struct bio_vec *bvec;
- int i, ret = 0;
+ int ret;
- __bio_for_each_segment(bvec, bio, i, 0) {
- char *addr = page_address(bvec->bv_page);
- unsigned int len = bmd->iovecs[i].bv_len;
+ ret = __bio_copy_iov(bio, bmd->sgvecs, bmd->nr_sgvecs, 1);
- if (read && !ret && copy_to_user(bmd->userptr, addr, len))
- ret = -EFAULT;
-
- __free_page(bvec->bv_page);
- bmd->userptr += len;
- }
bio_free_map_data(bmd);
bio_put(bio);
return ret;
}
/**
- * bio_copy_user - copy user data to bio
+ * bio_copy_user_iov - copy user data to bio
* @q: destination block queue
- * @uaddr: start of user address
- * @len: length in bytes
+ * @iov: the iovec.
+ * @iov_count: number of elements in the iovec
* @write_to_vm: bool indicating writing to pages or not
*
* Prepares and returns a bio for indirect user io, bouncing data
* to/from kernel pages as necessary. Must be paired with
* call bio_uncopy_user() on io completion.
*/
-struct bio *bio_copy_user(struct request_queue *q, unsigned long uaddr,
- unsigned int len, int write_to_vm)
+struct bio *bio_copy_user_iov(struct request_queue *q, struct sg_iovec *iov,
+ int iov_count, int write_to_vm)
{
- unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
- unsigned long start = uaddr >> PAGE_SHIFT;
struct bio_map_data *bmd;
struct bio_vec *bvec;
struct page *page;
struct bio *bio;
int i, ret;
+ int nr_pages = 0;
+ unsigned int len = 0;
- bmd = bio_alloc_map_data(end - start);
+ for (i = 0; i < iov_count; 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;
+ start = uaddr >> PAGE_SHIFT;
+
+ nr_pages += end - start;
+ len += iov[i].iov_len;
+ }
+
+ bmd = bio_alloc_map_data(nr_pages, iov_count);
if (!bmd)
return ERR_PTR(-ENOMEM);
- bmd->userptr = (void __user *) uaddr;
-
ret = -ENOMEM;
- bio = bio_alloc(GFP_KERNEL, end - start);
+ bio = bio_alloc(GFP_KERNEL, nr_pages);
if (!bio)
goto out_bmd;
@@ -564,22 +628,12 @@ struct bio *bio_copy_user(struct request_queue *q, unsigned long uaddr,
* success
*/
if (!write_to_vm) {
- char __user *p = (char __user *) uaddr;
-
- /*
- * for a write, copy in data to kernel pages
- */
- ret = -EFAULT;
- bio_for_each_segment(bvec, bio, i) {
- char *addr = page_address(bvec->bv_page);
-
- if (copy_from_user(addr, p, bvec->bv_len))
- goto cleanup;
- p += bvec->bv_len;
- }
+ ret = __bio_copy_iov(bio, iov, iov_count, 0);
+ if (ret)
+ goto cleanup;
}
- bio_set_map_data(bmd, bio);
+ bio_set_map_data(bmd, bio, iov, iov_count);
return bio;
cleanup:
bio_for_each_segment(bvec, bio, i)
@@ -591,6 +645,28 @@ out_bmd:
return ERR_PTR(ret);
}
+/**
+ * bio_copy_user - copy user data to bio
+ * @q: destination block queue
+ * @uaddr: start of user address
+ * @len: length in bytes
+ * @write_to_vm: bool indicating writing to pages or not
+ *
+ * Prepares and returns a bio for indirect user io, bouncing data
+ * to/from kernel pages as necessary. Must be paired with
+ * call bio_uncopy_user() on io completion.
+ */
+struct bio *bio_copy_user(struct request_queue *q, unsigned long uaddr,
+ unsigned int len, int write_to_vm)
+{
+ struct sg_iovec iov;
+
+ iov.iov_base = (void __user *)uaddr;
+ iov.iov_len = len;
+
+ return bio_copy_user_iov(q, &iov, 1, write_to_vm);
+}
+
static struct bio *__bio_map_user_iov(struct request_queue *q,
struct block_device *bdev,
struct sg_iovec *iov, int iov_count,
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 4c59bdc..d259690 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -327,6 +327,8 @@ extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
extern void bio_set_pages_dirty(struct bio *bio);
extern void bio_check_pages_dirty(struct bio *bio);
extern struct bio *bio_copy_user(struct request_queue *, unsigned long, unsigned int, int);
+extern struct bio *bio_copy_user_iov(struct request_queue *, struct sg_iovec *,
+ int, int);
extern int bio_uncopy_user(struct bio *);
void zero_fill_bio(struct bio *bio);
--
1.5.4.2
--
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