* break badly! cannot be bigger than what you can fit into an
* unsigned short
*/
-#define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
+#define BV(x, n) { .nr_vecs = x, .name = "biovec-"#n }
static struct biovec_slab bvec_slabs[BVEC_POOL_NR] __read_mostly = {
- BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES),
+ BV(1, 1), BV(4, 4), BV(16, 16), BV(64, 64), BV(128, 128), BV(BIO_MAX_PAGES, max),
};
#undef BV
unsigned int bvec_nr_vecs(unsigned short idx)
{
- return bvec_slabs[idx].nr_vecs;
+ return bvec_slabs[--idx].nr_vecs;
}
void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned int idx)
return 0;
}
- if (bio->bi_vcnt >= bio->bi_max_vecs)
+ if (bio_full(bio))
return 0;
/*
EXPORT_SYMBOL(bio_add_pc_page);
/**
- * bio_add_page - attempt to add page to bio
- * @bio: destination bio
- * @page: page to add
- * @len: vec entry length
- * @offset: vec entry offset
+ * __bio_try_merge_page - try appending data to an existing bvec.
+ * @bio: destination bio
+ * @page: page to add
+ * @len: length of the data to add
+ * @off: offset of the data in @page
*
- * Attempt to add a page to the bio_vec maplist. This will only fail
- * if either bio->bi_vcnt == bio->bi_max_vecs or it's a cloned bio.
+ * Try to add the data at @page + @off to the last bvec of @bio. This is a
+ * a useful optimisation for file systems with a block size smaller than the
+ * page size.
+ *
+ * Return %true on success or %false on failure.
*/
-int bio_add_page(struct bio *bio, struct page *page,
- unsigned int len, unsigned int offset)
+bool __bio_try_merge_page(struct bio *bio, struct page *page,
+ unsigned int len, unsigned int off)
{
- struct bio_vec *bv;
-
- /*
- * cloned bio must not modify vec list
- */
if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
- return 0;
+ return false;
- /*
- * For filesystems with a blocksize smaller than the pagesize
- * we will often be called with the same page as last time and
- * a consecutive offset. Optimize this special case.
- */
if (bio->bi_vcnt > 0) {
- bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
+ struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
- if (page == bv->bv_page &&
- offset == bv->bv_offset + bv->bv_len) {
+ if (page == bv->bv_page && off == bv->bv_offset + bv->bv_len) {
bv->bv_len += len;
- goto done;
+ bio->bi_iter.bi_size += len;
+ return true;
}
}
+ return false;
+}
+EXPORT_SYMBOL_GPL(__bio_try_merge_page);
- if (bio->bi_vcnt >= bio->bi_max_vecs)
- return 0;
+/**
+ * __bio_add_page - add page to a bio in a new segment
+ * @bio: destination bio
+ * @page: page to add
+ * @len: length of the data to add
+ * @off: offset of the data in @page
+ *
+ * Add the data at @page + @off to @bio as a new bvec. The caller must ensure
+ * that @bio has space for another bvec.
+ */
+void __bio_add_page(struct bio *bio, struct page *page,
+ unsigned int len, unsigned int off)
+{
+ struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt];
- bv = &bio->bi_io_vec[bio->bi_vcnt];
- bv->bv_page = page;
- bv->bv_len = len;
- bv->bv_offset = offset;
+ WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
+ WARN_ON_ONCE(bio_full(bio));
+
+ bv->bv_page = page;
+ bv->bv_offset = off;
+ bv->bv_len = len;
- bio->bi_vcnt++;
-done:
bio->bi_iter.bi_size += len;
+ bio->bi_vcnt++;
+}
+EXPORT_SYMBOL_GPL(__bio_add_page);
+
+/**
+ * bio_add_page - attempt to add page to bio
+ * @bio: destination bio
+ * @page: page to add
+ * @len: vec entry length
+ * @offset: vec entry offset
+ *
+ * Attempt to add a page to the bio_vec maplist. This will only fail
+ * if either bio->bi_vcnt == bio->bi_max_vecs or it's a cloned bio.
+ */
+int bio_add_page(struct bio *bio, struct page *page,
+ unsigned int len, unsigned int offset)
+{
+ if (!__bio_try_merge_page(bio, page, len, offset)) {
+ if (bio_full(bio))
+ return 0;
+ __bio_add_page(bio, page, len, offset);
+ }
return len;
}
EXPORT_SYMBOL(bio_add_page);
/**
- * bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio
+ * __bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio
* @bio: bio to add pages to
* @iter: iov iterator describing the region to be mapped
*
- * Pins as many pages from *iter and appends them to @bio's bvec array. The
+ * Pins pages from *iter and appends them to @bio's bvec array. The
* pages will have to be released using put_page() when done.
+ * For multi-segment *iter, this function only adds pages from the
+ * the next non-empty segment of the iov iterator.
*/
-int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
+static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
{
- unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt;
+ unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt, idx;
struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt;
struct page **pages = (struct page **)bv;
- size_t offset, diff;
+ size_t offset;
ssize_t size;
size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset);
if (unlikely(size <= 0))
return size ? size : -EFAULT;
- nr_pages = (size + offset + PAGE_SIZE - 1) / PAGE_SIZE;
+ idx = nr_pages = (size + offset + PAGE_SIZE - 1) / PAGE_SIZE;
/*
* Deep magic below: We need to walk the pinned pages backwards
bio->bi_iter.bi_size += size;
bio->bi_vcnt += nr_pages;
- diff = (nr_pages * PAGE_SIZE - offset) - size;
- while (nr_pages--) {
- bv[nr_pages].bv_page = pages[nr_pages];
- bv[nr_pages].bv_len = PAGE_SIZE;
- bv[nr_pages].bv_offset = 0;
+ while (idx--) {
+ bv[idx].bv_page = pages[idx];
+ bv[idx].bv_len = PAGE_SIZE;
+ bv[idx].bv_offset = 0;
}
bv[0].bv_offset += offset;
bv[0].bv_len -= offset;
- if (diff)
- bv[bio->bi_vcnt - 1].bv_len -= diff;
+ bv[nr_pages - 1].bv_len -= nr_pages * PAGE_SIZE - offset - size;
iov_iter_advance(iter, size);
return 0;
}
+
+/**
+ * bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio
+ * @bio: bio to add pages to
+ * @iter: iov iterator describing the region to be mapped
+ *
+ * Pins pages from *iter and appends them to @bio's bvec array. The
+ * pages will have to be released using put_page() when done.
+ * The function tries, but does not guarantee, to pin as many pages as
+ * fit into the bio, or are requested in *iter, whatever is smaller.
+ * If MM encounters an error pinning the requested pages, it stops.
+ * Error is returned only if 0 pages could be pinned.
+ */
+int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
+{
+ unsigned short orig_vcnt = bio->bi_vcnt;
+
+ do {
+ int ret = __bio_iov_iter_get_pages(bio, iter);
+
+ if (unlikely(ret))
+ return bio->bi_vcnt > orig_vcnt ? 0 : ret;
+
+ } while (iov_iter_count(iter) && !bio_full(bio));
+
+ return 0;
+}
EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages);
static void submit_bio_wait_endio(struct bio *bio)
}
}
- if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
+ 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;
} else {
+ if (bmd->is_our_pages)
+ zero_fill_bio(bio);
iov_iter_advance(iter, bio->bi_iter.bi_size);
}
bio_integrity_trim(split);
bio_advance(bio, split->bi_iter.bi_size);
+ bio->bi_iter.bi_done = 0;
if (bio_flagged(bio, BIO_TRACE_COMPLETION))
- bio_set_flag(bio, BIO_TRACE_COMPLETION);
+ bio_set_flag(split, BIO_TRACE_COMPLETION);
return split;
}
projects / mirror_ubuntu-bionic-kernel.git / blobdiff