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https://github.com/brain-hackers/linux-brain.git
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block: convert bio_copy_user to bio_copy_user_iov
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@lab.ntt.co.jp> Cc: Tejun Heo <htejun@gmail.com> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
FUJITA Tomonori
Jens Axboe
parent
476a4813cf
commit
c5dec1c303
158
fs/bio.c
158
fs/bio.c
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@ -444,22 +444,27 @@ int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
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struct bio_map_data {
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struct bio_vec *iovecs;
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void __user *userptr;
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int nr_sgvecs;
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struct sg_iovec *sgvecs;
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};
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static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio)
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static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio,
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struct sg_iovec *iov, int iov_count)
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{
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memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
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memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count);
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bmd->nr_sgvecs = iov_count;
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bio->bi_private = bmd;
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}
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static void bio_free_map_data(struct bio_map_data *bmd)
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{
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kfree(bmd->iovecs);
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kfree(bmd->sgvecs);
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kfree(bmd);
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}
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static struct bio_map_data *bio_alloc_map_data(int nr_segs)
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static struct bio_map_data *bio_alloc_map_data(int nr_segs, int iov_count)
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{
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struct bio_map_data *bmd = kmalloc(sizeof(*bmd), GFP_KERNEL);
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@ -467,13 +472,71 @@ static struct bio_map_data *bio_alloc_map_data(int nr_segs)
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return NULL;
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bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, GFP_KERNEL);
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if (bmd->iovecs)
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if (!bmd->iovecs) {
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kfree(bmd);
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return NULL;
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}
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bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, GFP_KERNEL);
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if (bmd->sgvecs)
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return bmd;
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kfree(bmd->iovecs);
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kfree(bmd);
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return NULL;
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}
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static int __bio_copy_iov(struct bio *bio, struct sg_iovec *iov, int iov_count,
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int uncopy)
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{
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int ret = 0, i;
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struct bio_vec *bvec;
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int iov_idx = 0;
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unsigned int iov_off = 0;
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int read = bio_data_dir(bio) == READ;
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__bio_for_each_segment(bvec, bio, i, 0) {
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char *bv_addr = page_address(bvec->bv_page);
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unsigned int bv_len = bvec->bv_len;
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while (bv_len && iov_idx < iov_count) {
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unsigned int bytes;
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char *iov_addr;
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bytes = min_t(unsigned int,
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iov[iov_idx].iov_len - iov_off, bv_len);
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iov_addr = iov[iov_idx].iov_base + iov_off;
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if (!ret) {
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if (!read && !uncopy)
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ret = copy_from_user(bv_addr, iov_addr,
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bytes);
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if (read && uncopy)
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ret = copy_to_user(iov_addr, bv_addr,
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bytes);
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if (ret)
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ret = -EFAULT;
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}
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bv_len -= bytes;
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bv_addr += bytes;
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iov_addr += bytes;
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iov_off += bytes;
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if (iov[iov_idx].iov_len == iov_off) {
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iov_idx++;
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iov_off = 0;
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}
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}
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if (uncopy)
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__free_page(bvec->bv_page);
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}
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return ret;
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}
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/**
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* bio_uncopy_user - finish previously mapped bio
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* @bio: bio being terminated
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@ -484,55 +547,56 @@ static struct bio_map_data *bio_alloc_map_data(int nr_segs)
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int bio_uncopy_user(struct bio *bio)
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{
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struct bio_map_data *bmd = bio->bi_private;
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const int read = bio_data_dir(bio) == READ;
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struct bio_vec *bvec;
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int i, ret = 0;
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int ret;
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__bio_for_each_segment(bvec, bio, i, 0) {
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char *addr = page_address(bvec->bv_page);
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unsigned int len = bmd->iovecs[i].bv_len;
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ret = __bio_copy_iov(bio, bmd->sgvecs, bmd->nr_sgvecs, 1);
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if (read && !ret && copy_to_user(bmd->userptr, addr, len))
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ret = -EFAULT;
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__free_page(bvec->bv_page);
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bmd->userptr += len;
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}
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bio_free_map_data(bmd);
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bio_put(bio);
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return ret;
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}
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/**
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* bio_copy_user - copy user data to bio
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* bio_copy_user_iov - copy user data to bio
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* @q: destination block queue
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* @uaddr: start of user address
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* @len: length in bytes
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* @iov: the iovec.
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* @iov_count: number of elements in the iovec
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* @write_to_vm: bool indicating writing to pages or not
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*
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* Prepares and returns a bio for indirect user io, bouncing data
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* to/from kernel pages as necessary. Must be paired with
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* call bio_uncopy_user() on io completion.
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*/
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struct bio *bio_copy_user(struct request_queue *q, unsigned long uaddr,
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unsigned int len, int write_to_vm)
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struct bio *bio_copy_user_iov(struct request_queue *q, struct sg_iovec *iov,
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int iov_count, int write_to_vm)
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{
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unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
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unsigned long start = uaddr >> PAGE_SHIFT;
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struct bio_map_data *bmd;
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struct bio_vec *bvec;
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struct page *page;
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struct bio *bio;
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int i, ret;
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int nr_pages = 0;
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unsigned int len = 0;
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bmd = bio_alloc_map_data(end - start);
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for (i = 0; i < iov_count; i++) {
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unsigned long uaddr;
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unsigned long end;
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unsigned long start;
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uaddr = (unsigned long)iov[i].iov_base;
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end = (uaddr + iov[i].iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
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start = uaddr >> PAGE_SHIFT;
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nr_pages += end - start;
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len += iov[i].iov_len;
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}
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bmd = bio_alloc_map_data(nr_pages, iov_count);
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if (!bmd)
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return ERR_PTR(-ENOMEM);
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bmd->userptr = (void __user *) uaddr;
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ret = -ENOMEM;
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bio = bio_alloc(GFP_KERNEL, end - start);
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bio = bio_alloc(GFP_KERNEL, nr_pages);
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if (!bio)
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goto out_bmd;
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@ -564,22 +628,12 @@ struct bio *bio_copy_user(struct request_queue *q, unsigned long uaddr,
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* success
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*/
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if (!write_to_vm) {
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char __user *p = (char __user *) uaddr;
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/*
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* for a write, copy in data to kernel pages
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*/
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ret = -EFAULT;
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bio_for_each_segment(bvec, bio, i) {
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char *addr = page_address(bvec->bv_page);
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if (copy_from_user(addr, p, bvec->bv_len))
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goto cleanup;
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p += bvec->bv_len;
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}
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ret = __bio_copy_iov(bio, iov, iov_count, 0);
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if (ret)
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goto cleanup;
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}
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bio_set_map_data(bmd, bio);
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bio_set_map_data(bmd, bio, iov, iov_count);
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return bio;
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cleanup:
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bio_for_each_segment(bvec, bio, i)
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@ -591,6 +645,28 @@ struct bio *bio_copy_user(struct request_queue *q, unsigned long uaddr,
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return ERR_PTR(ret);
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}
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/**
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* bio_copy_user - copy user data to bio
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* @q: destination block queue
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* @uaddr: start of user address
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* @len: length in bytes
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* @write_to_vm: bool indicating writing to pages or not
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*
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* Prepares and returns a bio for indirect user io, bouncing data
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* to/from kernel pages as necessary. Must be paired with
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* call bio_uncopy_user() on io completion.
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*/
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struct bio *bio_copy_user(struct request_queue *q, unsigned long uaddr,
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unsigned int len, int write_to_vm)
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{
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struct sg_iovec iov;
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iov.iov_base = (void __user *)uaddr;
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iov.iov_len = len;
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return bio_copy_user_iov(q, &iov, 1, write_to_vm);
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}
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static struct bio *__bio_map_user_iov(struct request_queue *q,
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struct block_device *bdev,
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struct sg_iovec *iov, int iov_count,
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@ -327,6 +327,8 @@ extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
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extern void bio_set_pages_dirty(struct bio *bio);
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extern void bio_check_pages_dirty(struct bio *bio);
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extern struct bio *bio_copy_user(struct request_queue *, unsigned long, unsigned int, int);
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extern struct bio *bio_copy_user_iov(struct request_queue *, struct sg_iovec *,
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int, int);
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extern int bio_uncopy_user(struct bio *);
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void zero_fill_bio(struct bio *bio);
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