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提交 130879f1 编写于 作者: C Christoph Hellwig 提交者： Jens Axboe
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block: move bio_map_* to blk-map.c 

The bio_map_* helpers are just the low-level helpers for the
blk_rq_map_* APIs.  Move them together for better logical grouping,
as no there isn't much overlap with other code in bio.c.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
上级 f01b411f
隐藏空白更改
内联 并排
Showing with 513 addition and 523 deletion
block/bio.c
浏览文件 @ 130879f1
......@@ -780,7 +780,7 @@ static bool bio_try_merge_pc_page(struct request_queue *q, struct bio *bio,
*
* This should only be used by passthrough bios.
*/
static int __bio_add_pc_page(struct request_queue *q, struct bio *bio,
int __bio_add_pc_page(struct request_queue *q, struct bio *bio,
struct page *page, unsigned int len, unsigned int offset,
bool *same_page)
{
......@@ -1194,90 +1194,6 @@ void bio_list_copy_data(struct bio *dst, struct bio *src)
}
EXPORT_SYMBOL(bio_list_copy_data);
struct bio_map_data {
int is_our_pages;
struct iov_iter iter;
struct iovec iov[];
};
static struct bio_map_data *bio_alloc_map_data(struct iov_iter *data,
gfp_t gfp_mask)
{
struct bio_map_data *bmd;
if (data->nr_segs > UIO_MAXIOV)
return NULL;
bmd = kmalloc(struct_size(bmd, iov, data->nr_segs), gfp_mask);
if (!bmd)
return NULL;
memcpy(bmd->iov, data->iov, sizeof(struct iovec) * data->nr_segs);
bmd->iter = *data;
bmd->iter.iov = bmd->iov;
return bmd;
}
/**
* bio_copy_from_iter - copy all pages from iov_iter to bio
* @bio: The &struct bio which describes the I/O as destination
* @iter: iov_iter as source
*
* Copy all pages from iov_iter to bio.
* Returns 0 on success, or error on failure.
*/
static int bio_copy_from_iter(struct bio *bio, struct iov_iter *iter)
{
struct bio_vec *bvec;
struct bvec_iter_all iter_all;
bio_for_each_segment_all(bvec, bio, iter_all) {
ssize_t ret;
ret = copy_page_from_iter(bvec->bv_page,
bvec->bv_offset,
bvec->bv_len,
iter);
if (!iov_iter_count(iter))
break;
if (ret < bvec->bv_len)
return -EFAULT;
}
return 0;
}
/**
* bio_copy_to_iter - copy all pages from bio to iov_iter
* @bio: The &struct bio which describes the I/O as source
* @iter: iov_iter as destination
*
* Copy all pages from bio to iov_iter.
* Returns 0 on success, or error on failure.
*/
static int bio_copy_to_iter(struct bio *bio, struct iov_iter iter)
{
struct bio_vec *bvec;
struct bvec_iter_all iter_all;
bio_for_each_segment_all(bvec, bio, iter_all) {
ssize_t ret;
ret = copy_page_to_iter(bvec->bv_page,
bvec->bv_offset,
bvec->bv_len,
&iter);
if (!iov_iter_count(&iter))
break;
if (ret < bvec->bv_len)
return -EFAULT;
}
return 0;
}
void bio_free_pages(struct bio *bio)
{
struct bio_vec *bvec;
......@@ -1288,430 +1204,6 @@ void bio_free_pages(struct bio *bio)
}
EXPORT_SYMBOL(bio_free_pages);
/**
* bio_uncopy_user - finish previously mapped bio
* @bio: bio being terminated
*
* Free pages allocated from bio_copy_user_iov() and write back data
* to user space in case of a read.
*/
int bio_uncopy_user(struct bio *bio)
{
struct bio_map_data *bmd = bio->bi_private;
int ret = 0;
if (!bio_flagged(bio, BIO_NULL_MAPPED)) {
/*
* if we're in a workqueue, the request is orphaned, so
* don't copy into a random user address space, just free
* and return -EINTR so user space doesn't expect any data.
*/
if (!current->mm)
ret = -EINTR;
else if (bio_data_dir(bio) == READ)
ret = bio_copy_to_iter(bio, bmd->iter);
if (bmd->is_our_pages)
bio_free_pages(bio);
}
kfree(bmd);
bio_put(bio);
return ret;
}
/**
* 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)
* @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
* call bio_uncopy_user() on io completion.
*/
struct bio *bio_copy_user_iov(struct request_queue *q,
struct rq_map_data *map_data,
struct iov_iter *iter,
gfp_t gfp_mask)
{
struct bio_map_data *bmd;
struct page *page;
struct bio *bio;
int i = 0, ret;
int nr_pages;
unsigned int len = iter->count;
unsigned int offset = map_data ? offset_in_page(map_data->offset) : 0;
bmd = bio_alloc_map_data(iter, 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;
nr_pages = DIV_ROUND_UP(offset + len, PAGE_SIZE);
if (nr_pages > BIO_MAX_PAGES)
nr_pages = BIO_MAX_PAGES;
ret = -ENOMEM;
bio = bio_kmalloc(gfp_mask, nr_pages);
if (!bio)
goto out_bmd;
ret = 0;
if (map_data) {
nr_pages = 1 << map_data->page_order;
i = map_data->offset / PAGE_SIZE;
}
while (len) {
unsigned int bytes = PAGE_SIZE;
bytes -= offset;
if (bytes > len)
bytes = len;
if (map_data) {
if (i == map_data->nr_entries * nr_pages) {
ret = -ENOMEM;
break;
}
page = map_data->pages[i / nr_pages];
page += (i % nr_pages);
i++;
} else {
page = alloc_page(q->bounce_gfp | gfp_mask);
if (!page) {
ret = -ENOMEM;
break;
}
}
if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes) {
if (!map_data)
__free_page(page);
break;
}
len -= bytes;
offset = 0;
}
if (ret)
goto cleanup;
if (map_data)
map_data->offset += bio->bi_iter.bi_size;
/*
* success
*/
if ((iov_iter_rw(iter) == WRITE && (!map_data || !map_data->null_mapped)) ||
(map_data && map_data->from_user)) {
ret = bio_copy_from_iter(bio, iter);
if (ret)
goto cleanup;
} else {
if (bmd->is_our_pages)
zero_fill_bio(bio);
iov_iter_advance(iter, bio->bi_iter.bi_size);
}
bio->bi_private = bmd;
if (map_data && map_data->null_mapped)
bio_set_flag(bio, BIO_NULL_MAPPED);
return bio;
cleanup:
if (!map_data)
bio_free_pages(bio);
bio_put(bio);
out_bmd:
kfree(bmd);
return ERR_PTR(ret);
}
/**
* bio_map_user_iov - map user iovec into bio
* @q: the struct request_queue for the bio
* @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 iov_iter *iter,
gfp_t gfp_mask)
{
int j;
struct bio *bio;
int ret;
if (!iov_iter_count(iter))
return ERR_PTR(-EINVAL);
bio = bio_kmalloc(gfp_mask, iov_iter_npages(iter, BIO_MAX_PAGES));
if (!bio)
return ERR_PTR(-ENOMEM);
while (iov_iter_count(iter)) {
struct page **pages;
ssize_t bytes;
size_t offs, added = 0;
int npages;
bytes = iov_iter_get_pages_alloc(iter, &pages, LONG_MAX, &offs);
if (unlikely(bytes <= 0)) {
ret = bytes ? bytes : -EFAULT;
goto out_unmap;
}
npages = DIV_ROUND_UP(offs + bytes, PAGE_SIZE);
if (unlikely(offs & queue_dma_alignment(q))) {
ret = -EINVAL;
j = 0;
} else {
for (j = 0; j < npages; j++) {
struct page *page = pages[j];
unsigned int n = PAGE_SIZE - offs;
bool same_page = false;
if (n > bytes)
n = bytes;
if (!__bio_add_pc_page(q, bio, page, n, offs,
&same_page)) {
if (same_page)
put_page(page);
break;
}
added += n;
bytes -= n;
offs = 0;
}
iov_iter_advance(iter, added);
}
/*
* release the pages we didn't map into the bio, if any
*/
while (j < npages)
put_page(pages[j++]);
kvfree(pages);
/* couldn't stuff something into bio? */
if (bytes)
break;
}
bio_set_flag(bio, BIO_USER_MAPPED);
/*
* subtle -- if bio_map_user_iov() ended up bouncing a bio,
* it would normally disappear when its bi_end_io is run.
* however, we need it for the unmap, so grab an extra
* reference to it
*/
bio_get(bio);
return bio;
out_unmap:
bio_release_pages(bio, false);
bio_put(bio);
return ERR_PTR(ret);
}
/**
* bio_unmap_user - unmap a bio
* @bio: the bio being unmapped
*
* Unmap a bio previously mapped by bio_map_user_iov(). Must be called from
* process context.
*
* bio_unmap_user() may sleep.
*/
void bio_unmap_user(struct bio *bio)
{
bio_release_pages(bio, bio_data_dir(bio) == READ);
bio_put(bio);
bio_put(bio);
}
static void bio_invalidate_vmalloc_pages(struct bio *bio)
{
#ifdef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
if (bio->bi_private && !op_is_write(bio_op(bio))) {
unsigned long i, len = 0;
for (i = 0; i < bio->bi_vcnt; i++)
len += bio->bi_io_vec[i].bv_len;
invalidate_kernel_vmap_range(bio->bi_private, len);
}
#endif
}
static void bio_map_kern_endio(struct bio *bio)
{
bio_invalidate_vmalloc_pages(bio);
bio_put(bio);
}
/**
* bio_map_kern - map kernel address into bio
* @q: the struct request_queue for the bio
* @data: pointer to buffer to map
* @len: length in bytes
* @gfp_mask: allocation flags for bio allocation
*
* Map the kernel address into a bio suitable for io to a block
* device. Returns an error pointer in case of error.
*/
struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
gfp_t gfp_mask)
{
unsigned long kaddr = (unsigned long)data;
unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
unsigned long start = kaddr >> PAGE_SHIFT;
const int nr_pages = end - start;
bool is_vmalloc = is_vmalloc_addr(data);
struct page *page;
int offset, i;
struct bio *bio;
bio = bio_kmalloc(gfp_mask, nr_pages);
if (!bio)
return ERR_PTR(-ENOMEM);
if (is_vmalloc) {
flush_kernel_vmap_range(data, len);
bio->bi_private = data;
}
offset = offset_in_page(kaddr);
for (i = 0; i < nr_pages; i++) {
unsigned int bytes = PAGE_SIZE - offset;
if (len <= 0)
break;
if (bytes > len)
bytes = len;
if (!is_vmalloc)
page = virt_to_page(data);
else
page = vmalloc_to_page(data);
if (bio_add_pc_page(q, bio, page, bytes,
offset) < bytes) {
/* we don't support partial mappings */
bio_put(bio);
return ERR_PTR(-EINVAL);
}
data += bytes;
len -= bytes;
offset = 0;
}
bio->bi_end_io = bio_map_kern_endio;
return bio;
}
static void bio_copy_kern_endio(struct bio *bio)
{
bio_free_pages(bio);
bio_put(bio);
}
static void bio_copy_kern_endio_read(struct bio *bio)
{
char *p = bio->bi_private;
struct bio_vec *bvec;
struct bvec_iter_all iter_all;
bio_for_each_segment_all(bvec, bio, iter_all) {
memcpy(p, page_address(bvec->bv_page), bvec->bv_len);
p += bvec->bv_len;
}
bio_copy_kern_endio(bio);
}
/**
* bio_copy_kern - copy kernel address into bio
* @q: the struct request_queue for the bio
* @data: pointer to buffer to copy
* @len: length in bytes
* @gfp_mask: allocation flags for bio and page allocation
* @reading: data direction is READ
*
* copy the kernel address into a bio suitable for io to a block
* device. Returns an error pointer in case of error.
*/
struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
gfp_t gfp_mask, int reading)
{
unsigned long kaddr = (unsigned long)data;
unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
unsigned long start = kaddr >> PAGE_SHIFT;
struct bio *bio;
void *p = data;
int nr_pages = 0;
/*
* Overflow, abort
*/
if (end < start)
return ERR_PTR(-EINVAL);
nr_pages = end - start;
bio = bio_kmalloc(gfp_mask, nr_pages);
if (!bio)
return ERR_PTR(-ENOMEM);
while (len) {
struct page *page;
unsigned int bytes = PAGE_SIZE;
if (bytes > len)
bytes = len;
page = alloc_page(q->bounce_gfp | gfp_mask);
if (!page)
goto cleanup;
if (!reading)
memcpy(page_address(page), p, bytes);
if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes)
break;
len -= bytes;
p += bytes;
}
if (reading) {
bio->bi_end_io = bio_copy_kern_endio_read;
bio->bi_private = data;
} else {
bio->bi_end_io = bio_copy_kern_endio;
}
return bio;
cleanup:
bio_free_pages(bio);
bio_put(bio);
return ERR_PTR(-ENOMEM);
}
/*
* bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
* for performing direct-IO in BIOs.
......
block/blk-map.c
浏览文件 @ 130879f1
......@@ -11,6 +11,514 @@
#include "blk.h"
struct bio_map_data {
int is_our_pages;
struct iov_iter iter;
struct iovec iov[];
};
static struct bio_map_data *bio_alloc_map_data(struct iov_iter *data,
gfp_t gfp_mask)
{
struct bio_map_data *bmd;
if (data->nr_segs > UIO_MAXIOV)
return NULL;
bmd = kmalloc(struct_size(bmd, iov, data->nr_segs), gfp_mask);
if (!bmd)
return NULL;
memcpy(bmd->iov, data->iov, sizeof(struct iovec) * data->nr_segs);
bmd->iter = *data;
bmd->iter.iov = bmd->iov;
return bmd;
}
/**
* bio_copy_from_iter - copy all pages from iov_iter to bio
* @bio: The &struct bio which describes the I/O as destination
* @iter: iov_iter as source
*
* Copy all pages from iov_iter to bio.
* Returns 0 on success, or error on failure.
*/
static int bio_copy_from_iter(struct bio *bio, struct iov_iter *iter)
{
struct bio_vec *bvec;
struct bvec_iter_all iter_all;
bio_for_each_segment_all(bvec, bio, iter_all) {
ssize_t ret;
ret = copy_page_from_iter(bvec->bv_page,
bvec->bv_offset,
bvec->bv_len,
iter);
if (!iov_iter_count(iter))
break;
if (ret < bvec->bv_len)
return -EFAULT;
}
return 0;
}
/**
* bio_copy_to_iter - copy all pages from bio to iov_iter
* @bio: The &struct bio which describes the I/O as source
* @iter: iov_iter as destination
*
* Copy all pages from bio to iov_iter.
* Returns 0 on success, or error on failure.
*/
static int bio_copy_to_iter(struct bio *bio, struct iov_iter iter)
{
struct bio_vec *bvec;
struct bvec_iter_all iter_all;
bio_for_each_segment_all(bvec, bio, iter_all) {
ssize_t ret;
ret = copy_page_to_iter(bvec->bv_page,
bvec->bv_offset,
bvec->bv_len,
&iter);
if (!iov_iter_count(&iter))
break;
if (ret < bvec->bv_len)
return -EFAULT;
}
return 0;
}
/**
* bio_uncopy_user - finish previously mapped bio
* @bio: bio being terminated
*
* Free pages allocated from bio_copy_user_iov() and write back data
* to user space in case of a read.
*/
static int bio_uncopy_user(struct bio *bio)
{
struct bio_map_data *bmd = bio->bi_private;
int ret = 0;
if (!bio_flagged(bio, BIO_NULL_MAPPED)) {
/*
* if we're in a workqueue, the request is orphaned, so
* don't copy into a random user address space, just free
* and return -EINTR so user space doesn't expect any data.
*/
if (!current->mm)
ret = -EINTR;
else if (bio_data_dir(bio) == READ)
ret = bio_copy_to_iter(bio, bmd->iter);
if (bmd->is_our_pages)
bio_free_pages(bio);
}
kfree(bmd);
bio_put(bio);
return ret;
}
/**
* 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)
* @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
* call bio_uncopy_user() on io completion.
*/
static struct bio *bio_copy_user_iov(struct request_queue *q,
struct rq_map_data *map_data, struct iov_iter *iter,
gfp_t gfp_mask)
{
struct bio_map_data *bmd;
struct page *page;
struct bio *bio;
int i = 0, ret;
int nr_pages;
unsigned int len = iter->count;
unsigned int offset = map_data ? offset_in_page(map_data->offset) : 0;
bmd = bio_alloc_map_data(iter, 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;
nr_pages = DIV_ROUND_UP(offset + len, PAGE_SIZE);
if (nr_pages > BIO_MAX_PAGES)
nr_pages = BIO_MAX_PAGES;
ret = -ENOMEM;
bio = bio_kmalloc(gfp_mask, nr_pages);
if (!bio)
goto out_bmd;
ret = 0;
if (map_data) {
nr_pages = 1 << map_data->page_order;
i = map_data->offset / PAGE_SIZE;
}
while (len) {
unsigned int bytes = PAGE_SIZE;
bytes -= offset;
if (bytes > len)
bytes = len;
if (map_data) {
if (i == map_data->nr_entries * nr_pages) {
ret = -ENOMEM;
break;
}
page = map_data->pages[i / nr_pages];
page += (i % nr_pages);
i++;
} else {
page = alloc_page(q->bounce_gfp | gfp_mask);
if (!page) {
ret = -ENOMEM;
break;
}
}
if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes) {
if (!map_data)
__free_page(page);
break;
}
len -= bytes;
offset = 0;
}
if (ret)
goto cleanup;
if (map_data)
map_data->offset += bio->bi_iter.bi_size;
/*
* success
*/
if ((iov_iter_rw(iter) == WRITE &&
(!map_data || !map_data->null_mapped)) ||
(map_data && map_data->from_user)) {
ret = bio_copy_from_iter(bio, iter);
if (ret)
goto cleanup;
} else {
if (bmd->is_our_pages)
zero_fill_bio(bio);
iov_iter_advance(iter, bio->bi_iter.bi_size);
}
bio->bi_private = bmd;
if (map_data && map_data->null_mapped)
bio_set_flag(bio, BIO_NULL_MAPPED);
return bio;
cleanup:
if (!map_data)
bio_free_pages(bio);
bio_put(bio);
out_bmd:
kfree(bmd);
return ERR_PTR(ret);
}
/**
* bio_map_user_iov - map user iovec into bio
* @q: the struct request_queue for the bio
* @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.
*/
static struct bio *bio_map_user_iov(struct request_queue *q,
struct iov_iter *iter, gfp_t gfp_mask)
{
int j;
struct bio *bio;
int ret;
if (!iov_iter_count(iter))
return ERR_PTR(-EINVAL);
bio = bio_kmalloc(gfp_mask, iov_iter_npages(iter, BIO_MAX_PAGES));
if (!bio)
return ERR_PTR(-ENOMEM);
while (iov_iter_count(iter)) {
struct page **pages;
ssize_t bytes;
size_t offs, added = 0;
int npages;
bytes = iov_iter_get_pages_alloc(iter, &pages, LONG_MAX, &offs);
if (unlikely(bytes <= 0)) {
ret = bytes ? bytes : -EFAULT;
goto out_unmap;
}
npages = DIV_ROUND_UP(offs + bytes, PAGE_SIZE);
if (unlikely(offs & queue_dma_alignment(q))) {
ret = -EINVAL;
j = 0;
} else {
for (j = 0; j < npages; j++) {
struct page *page = pages[j];
unsigned int n = PAGE_SIZE - offs;
bool same_page = false;
if (n > bytes)
n = bytes;
if (!__bio_add_pc_page(q, bio, page, n, offs,
&same_page)) {
if (same_page)
put_page(page);
break;
}
added += n;
bytes -= n;
offs = 0;
}
iov_iter_advance(iter, added);
}
/*
* release the pages we didn't map into the bio, if any
*/
while (j < npages)
put_page(pages[j++]);
kvfree(pages);
/* couldn't stuff something into bio? */
if (bytes)
break;
}
bio_set_flag(bio, BIO_USER_MAPPED);
/*
* subtle -- if bio_map_user_iov() ended up bouncing a bio,
* it would normally disappear when its bi_end_io is run.
* however, we need it for the unmap, so grab an extra
* reference to it
*/
bio_get(bio);
return bio;
out_unmap:
bio_release_pages(bio, false);
bio_put(bio);
return ERR_PTR(ret);
}
/**
* bio_unmap_user - unmap a bio
* @bio: the bio being unmapped
*
* Unmap a bio previously mapped by bio_map_user_iov(). Must be called from
* process context.
*
* bio_unmap_user() may sleep.
*/
static void bio_unmap_user(struct bio *bio)
{
bio_release_pages(bio, bio_data_dir(bio) == READ);
bio_put(bio);
bio_put(bio);
}
static void bio_invalidate_vmalloc_pages(struct bio *bio)
{
#ifdef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
if (bio->bi_private && !op_is_write(bio_op(bio))) {
unsigned long i, len = 0;
for (i = 0; i < bio->bi_vcnt; i++)
len += bio->bi_io_vec[i].bv_len;
invalidate_kernel_vmap_range(bio->bi_private, len);
}
#endif
}
static void bio_map_kern_endio(struct bio *bio)
{
bio_invalidate_vmalloc_pages(bio);
bio_put(bio);
}
/**
* bio_map_kern - map kernel address into bio
* @q: the struct request_queue for the bio
* @data: pointer to buffer to map
* @len: length in bytes
* @gfp_mask: allocation flags for bio allocation
*
* Map the kernel address into a bio suitable for io to a block
* device. Returns an error pointer in case of error.
*/
static struct bio *bio_map_kern(struct request_queue *q, void *data,
unsigned int len, gfp_t gfp_mask)
{
unsigned long kaddr = (unsigned long)data;
unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
unsigned long start = kaddr >> PAGE_SHIFT;
const int nr_pages = end - start;
bool is_vmalloc = is_vmalloc_addr(data);
struct page *page;
int offset, i;
struct bio *bio;
bio = bio_kmalloc(gfp_mask, nr_pages);
if (!bio)
return ERR_PTR(-ENOMEM);
if (is_vmalloc) {
flush_kernel_vmap_range(data, len);
bio->bi_private = data;
}
offset = offset_in_page(kaddr);
for (i = 0; i < nr_pages; i++) {
unsigned int bytes = PAGE_SIZE - offset;
if (len <= 0)
break;
if (bytes > len)
bytes = len;
if (!is_vmalloc)
page = virt_to_page(data);
else
page = vmalloc_to_page(data);
if (bio_add_pc_page(q, bio, page, bytes,
offset) < bytes) {
/* we don't support partial mappings */
bio_put(bio);
return ERR_PTR(-EINVAL);
}
data += bytes;
len -= bytes;
offset = 0;
}
bio->bi_end_io = bio_map_kern_endio;
return bio;
}
static void bio_copy_kern_endio(struct bio *bio)
{
bio_free_pages(bio);
bio_put(bio);
}
static void bio_copy_kern_endio_read(struct bio *bio)
{
char *p = bio->bi_private;
struct bio_vec *bvec;
struct bvec_iter_all iter_all;
bio_for_each_segment_all(bvec, bio, iter_all) {
memcpy(p, page_address(bvec->bv_page), bvec->bv_len);
p += bvec->bv_len;
}
bio_copy_kern_endio(bio);
}
/**
* bio_copy_kern - copy kernel address into bio
* @q: the struct request_queue for the bio
* @data: pointer to buffer to copy
* @len: length in bytes
* @gfp_mask: allocation flags for bio and page allocation
* @reading: data direction is READ
*
* copy the kernel address into a bio suitable for io to a block
* device. Returns an error pointer in case of error.
*/
static struct bio *bio_copy_kern(struct request_queue *q, void *data,
unsigned int len, gfp_t gfp_mask, int reading)
{
unsigned long kaddr = (unsigned long)data;
unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
unsigned long start = kaddr >> PAGE_SHIFT;
struct bio *bio;
void *p = data;
int nr_pages = 0;
/*
* Overflow, abort
*/
if (end < start)
return ERR_PTR(-EINVAL);
nr_pages = end - start;
bio = bio_kmalloc(gfp_mask, nr_pages);
if (!bio)
return ERR_PTR(-ENOMEM);
while (len) {
struct page *page;
unsigned int bytes = PAGE_SIZE;
if (bytes > len)
bytes = len;
page = alloc_page(q->bounce_gfp | gfp_mask);
if (!page)
goto cleanup;
if (!reading)
memcpy(page_address(page), p, bytes);
if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes)
break;
len -= bytes;
p += bytes;
}
if (reading) {
bio->bi_end_io = bio_copy_kern_endio_read;
bio->bi_private = data;
} else {
bio->bi_end_io = bio_copy_kern_endio;
}
return bio;
cleanup:
bio_free_pages(bio);
bio_put(bio);
return ERR_PTR(-ENOMEM);
}
/*
* Append a bio to a passthrough request. Only works if the bio can be merged
* into the request based on the driver constraints.
......
block/blk.h
浏览文件 @ 130879f1
......@@ -484,4 +484,8 @@ static inline void part_nr_sects_write(struct hd_struct *part, sector_t size)
struct request_queue *__blk_alloc_queue(int node_id);
int __bio_add_pc_page(struct request_queue *q, struct bio *bio,
struct page *page, unsigned int len, unsigned int offset,
bool *same_page);
#endif /* BLK_INTERNAL_H */
include/linux/bio.h
浏览文件 @ 130879f1
......@@ -441,14 +441,6 @@ void __bio_add_page(struct bio *bio, struct page *page,
unsigned int len, unsigned int off);
int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
void bio_release_pages(struct bio *bio, bool mark_dirty);
struct rq_map_data;
extern struct bio *bio_map_user_iov(struct request_queue *,
struct iov_iter *, gfp_t);
extern void bio_unmap_user(struct bio *);
extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
gfp_t);
extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
gfp_t, int);
extern void bio_set_pages_dirty(struct bio *bio);
extern void bio_check_pages_dirty(struct bio *bio);
......@@ -463,12 +455,6 @@ extern void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
extern void bio_copy_data(struct bio *dst, struct bio *src);
extern void bio_list_copy_data(struct bio *dst, struct bio *src);
extern void bio_free_pages(struct bio *bio);
extern struct bio *bio_copy_user_iov(struct request_queue *,
struct rq_map_data *,
struct iov_iter *,
gfp_t);
extern int bio_uncopy_user(struct bio *);
void zero_fill_bio_iter(struct bio *bio, struct bvec_iter iter);
void bio_truncate(struct bio *bio, unsigned new_size);
void guard_bio_eod(struct bio *bio);
......
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