--- /dev/null
+/*
+ * Copyright (C) 2001 Jens Axboe <axboe@kernel.dk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public Licens
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
+ *
+ */
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/slab.h>
+#include <linux/kernel.h>
+
+static const struct {
+ int err;
+ const char *name;
+} blk_errors[] = {
+ [BLK_STS_OK] = { 0, "" },
+ [BLK_STS_NOTSUPP] = { -EOPNOTSUPP, "operation not supported" },
+ [BLK_STS_TIMEOUT] = { -ETIMEDOUT, "timeout" },
+ [BLK_STS_NOSPC] = { -ENOSPC, "critical space allocation" },
+ [BLK_STS_TRANSPORT] = { -ENOLINK, "recoverable transport" },
+ [BLK_STS_TARGET] = { -EREMOTEIO, "critical target" },
+ [BLK_STS_NEXUS] = { -EBADE, "critical nexus" },
+ [BLK_STS_MEDIUM] = { -ENODATA, "critical medium" },
+ [BLK_STS_PROTECTION] = { -EILSEQ, "protection" },
+ [BLK_STS_RESOURCE] = { -ENOMEM, "kernel resource" },
+ [BLK_STS_AGAIN] = { -EAGAIN, "nonblocking retry" },
+
+ /* device mapper special case, should not leak out: */
+ [BLK_STS_DM_REQUEUE] = { -EREMCHG, "dm internal retry" },
+
+ /* everything else not covered above: */
+ [BLK_STS_IOERR] = { -EIO, "I/O" },
+};
+
+int blk_status_to_errno(blk_status_t status)
+{
+ int idx = (__force int)status;
+
+ if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors)))
+ return -EIO;
+ return blk_errors[idx].err;
+}
+
+const char *blk_status_to_str(blk_status_t status)
+{
+ int idx = (__force int)status;
+
+ if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors)))
+ return "(invalid error)";
+ return blk_errors[idx].name;
+}
+
+void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
+ struct bio *src, struct bvec_iter *src_iter)
+{
+ struct bio_vec src_bv, dst_bv;
+ void *src_p, *dst_p;
+ unsigned bytes;
+
+ while (src_iter->bi_size && dst_iter->bi_size) {
+ src_bv = bio_iter_iovec(src, *src_iter);
+ dst_bv = bio_iter_iovec(dst, *dst_iter);
+
+ bytes = min(src_bv.bv_len, dst_bv.bv_len);
+
+ src_p = kmap_atomic(src_bv.bv_page);
+ dst_p = kmap_atomic(dst_bv.bv_page);
+
+ memcpy(dst_p + dst_bv.bv_offset,
+ src_p + src_bv.bv_offset,
+ bytes);
+
+ kunmap_atomic(dst_p);
+ kunmap_atomic(src_p);
+
+ flush_dcache_page(dst_bv.bv_page);
+
+ bio_advance_iter(src, src_iter, bytes);
+ bio_advance_iter(dst, dst_iter, bytes);
+ }
+}
+
+/**
+ * bio_copy_data - copy contents of data buffers from one bio to another
+ * @src: source bio
+ * @dst: destination bio
+ *
+ * Stops when it reaches the end of either @src or @dst - that is, copies
+ * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
+ */
+void bio_copy_data(struct bio *dst, struct bio *src)
+{
+ struct bvec_iter src_iter = src->bi_iter;
+ struct bvec_iter dst_iter = dst->bi_iter;
+
+ bio_copy_data_iter(dst, &dst_iter, src, &src_iter);
+}
+
+void zero_fill_bio_iter(struct bio *bio, struct bvec_iter start)
+{
+ unsigned long flags;
+ struct bio_vec bv;
+ struct bvec_iter iter;
+
+ __bio_for_each_segment(bv, bio, iter, start) {
+ char *data = bvec_kmap_irq(&bv, &flags);
+ memset(data, 0, bv.bv_len);
+ bvec_kunmap_irq(data, &flags);
+ }
+}
+
+static int __bio_clone(struct bio *bio, struct bio *bio_src, gfp_t gfp)
+{
+ bio_set_flag(bio, BIO_CLONED);
+ bio->bi_ioprio = bio_src->bi_ioprio;
+ bio->bi_iter = bio_src->bi_iter;
+ return 0;
+}
+
+struct bio *bio_alloc_clone(struct block_device *bdev, struct bio *bio_src,
+ gfp_t gfp, struct bio_set *bs)
+{
+ struct bio *bio;
+
+ bio = bio_alloc_bioset(bdev, 0, bio_src->bi_opf, gfp, bs);
+ if (!bio)
+ return NULL;
+
+ if (__bio_clone(bio, bio_src, gfp) < 0) {
+ bio_put(bio);
+ return NULL;
+ }
+ bio->bi_io_vec = bio_src->bi_io_vec;
+
+ return bio;
+}
+
+struct bio *bio_split(struct bio *bio, int sectors,
+ gfp_t gfp, struct bio_set *bs)
+{
+ struct bio *split = NULL;
+
+ BUG_ON(sectors <= 0);
+ BUG_ON(sectors >= bio_sectors(bio));
+
+ split = bio_alloc_clone(bio->bi_bdev, bio, gfp, bs);
+ if (!split)
+ return NULL;
+
+ split->bi_iter.bi_size = sectors << 9;
+
+ bio_advance(bio, split->bi_iter.bi_size);
+
+ return split;
+}
+
+void bio_free_pages(struct bio *bio)
+{
+ struct bvec_iter_all iter;
+ struct bio_vec *bvec;
+
+ bio_for_each_segment_all(bvec, bio, iter)
+ __free_page(bvec->bv_page);
+}
+
+void bio_advance(struct bio *bio, unsigned bytes)
+{
+ bio_advance_iter(bio, &bio->bi_iter, bytes);
+}
+
+static void bio_free(struct bio *bio)
+{
+ struct bio_set *bs = bio->bi_pool;
+
+ if (bs) {
+ if (bio->bi_max_vecs > BIO_INLINE_VECS)
+ mempool_free(bio->bi_io_vec, &bs->bvec_pool);
+
+ mempool_free((void *) bio - bs->front_pad, &bs->bio_pool);
+ } else {
+ kfree(bio);
+ }
+}
+
+void bio_put(struct bio *bio)
+{
+ if (!bio_flagged(bio, BIO_REFFED))
+ bio_free(bio);
+ else {
+ BUG_ON(!atomic_read(&bio->__bi_cnt));
+
+ /*
+ * last put frees it
+ */
+ if (atomic_dec_and_test(&bio->__bi_cnt))
+ bio_free(bio);
+ }
+}
+
+int 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];
+
+ WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
+ WARN_ON_ONCE(bio->bi_vcnt >= bio->bi_max_vecs);
+
+ bv->bv_page = page;
+ bv->bv_offset = off;
+ bv->bv_len = len;
+
+ bio->bi_iter.bi_size += len;
+ bio->bi_vcnt++;
+ return len;
+}
+
+static inline bool bio_remaining_done(struct bio *bio)
+{
+ /*
+ * If we're not chaining, then ->__bi_remaining is always 1 and
+ * we always end io on the first invocation.
+ */
+ if (!bio_flagged(bio, BIO_CHAIN))
+ return true;
+
+ BUG_ON(atomic_read(&bio->__bi_remaining) <= 0);
+
+ if (atomic_dec_and_test(&bio->__bi_remaining)) {
+ bio_clear_flag(bio, BIO_CHAIN);
+ return true;
+ }
+
+ return false;
+}
+
+static struct bio *__bio_chain_endio(struct bio *bio)
+{
+ struct bio *parent = bio->bi_private;
+
+ if (!parent->bi_status)
+ parent->bi_status = bio->bi_status;
+ bio_put(bio);
+ return parent;
+}
+
+static void bio_chain_endio(struct bio *bio)
+{
+ bio_endio(__bio_chain_endio(bio));
+}
+
+void bio_endio(struct bio *bio)
+{
+again:
+ if (!bio_remaining_done(bio))
+ return;
+
+ /*
+ * Need to have a real endio function for chained bios, otherwise
+ * various corner cases will break (like stacking block devices that
+ * save/restore bi_end_io) - however, we want to avoid unbounded
+ * recursion and blowing the stack. Tail call optimization would
+ * handle this, but compiling with frame pointers also disables
+ * gcc's sibling call optimization.
+ */
+ if (bio->bi_end_io == bio_chain_endio) {
+ bio = __bio_chain_endio(bio);
+ goto again;
+ }
+
+ if (bio->bi_end_io)
+ bio->bi_end_io(bio);
+}
+
+void bio_reset(struct bio *bio, struct block_device *bdev, unsigned int opf)
+{
+ unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS);
+
+ memset(bio, 0, BIO_RESET_BYTES);
+ bio->bi_bdev = bdev;
+ bio->bi_opf = opf;
+ bio->bi_flags = flags;
+ atomic_set(&bio->__bi_remaining, 1);
+}
+
+struct bio *bio_kmalloc(unsigned int nr_iovecs, gfp_t gfp_mask)
+{
+ struct bio *bio;
+
+ bio = kmalloc(sizeof(struct bio) +
+ sizeof(struct bio_vec) * nr_iovecs, gfp_mask);
+ if (unlikely(!bio))
+ return NULL;
+ bio_init(bio, NULL, nr_iovecs ? bio->bi_inline_vecs : NULL, nr_iovecs, 0);
+ bio->bi_pool = NULL;
+ return bio;
+}
+
+static struct bio_vec *bvec_alloc(mempool_t *pool, int *nr_vecs,
+ gfp_t gfp_mask)
+{
+ *nr_vecs = roundup_pow_of_two(*nr_vecs);
+ /*
+ * Try a slab allocation first for all smaller allocations. If that
+ * fails and __GFP_DIRECT_RECLAIM is set retry with the mempool.
+ * The mempool is sized to handle up to BIO_MAX_VECS entries.
+ */
+ if (*nr_vecs < BIO_MAX_VECS) {
+ struct bio_vec *bvl;
+
+ bvl = kmalloc(sizeof(*bvl) * *nr_vecs, gfp_mask);
+ if (likely(bvl))
+ return bvl;
+ *nr_vecs = BIO_MAX_VECS;
+ }
+
+ return mempool_alloc(pool, gfp_mask);
+}
+
+struct bio *bio_alloc_bioset(struct block_device *bdev,
+ unsigned nr_iovecs,
+ unsigned opf,
+ gfp_t gfp_mask,
+ struct bio_set *bs)
+{
+ struct bio *bio;
+ void *p;
+
+ if (nr_iovecs > BIO_MAX_VECS)
+ return NULL;
+
+ p = mempool_alloc(&bs->bio_pool, gfp_mask);
+ if (unlikely(!p))
+ return NULL;
+
+ bio = p + bs->front_pad;
+ if (nr_iovecs > BIO_INLINE_VECS) {
+ struct bio_vec *bvl = NULL;
+
+ bvl = bvec_alloc(&bs->bvec_pool, &nr_iovecs, gfp_mask);
+ if (unlikely(!bvl))
+ goto err_free;
+
+ bio_init(bio, bdev, bvl, nr_iovecs, opf);
+ } else if (nr_iovecs) {
+ bio_init(bio, bdev, bio->bi_inline_vecs, BIO_INLINE_VECS, opf);
+ } else {
+ bio_init(bio, bdev, NULL, 0, opf);
+ }
+
+ bio->bi_pool = bs;
+ return bio;
+
+err_free:
+ mempool_free(p, &bs->bio_pool);
+ return NULL;
+}
+
+void bioset_exit(struct bio_set *bs)
+{
+ mempool_exit(&bs->bio_pool);
+ mempool_exit(&bs->bvec_pool);
+}
+
+int bioset_init(struct bio_set *bs,
+ unsigned int pool_size,
+ unsigned int front_pad,
+ int flags)
+{
+ int ret;
+
+ bs->front_pad = front_pad;
+ if (flags & BIOSET_NEED_BVECS)
+ bs->back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
+ else
+ bs->back_pad = 0;
+
+ ret = mempool_init_kmalloc_pool(&bs->bio_pool, pool_size, bs->front_pad +
+ sizeof(struct bio) + bs->back_pad) ?:
+ mempool_init_kmalloc_pool(&bs->bvec_pool, pool_size,
+ sizeof(struct bio_vec) * BIO_MAX_VECS);
+ if (ret)
+ bioset_exit(bs);
+ return ret;
+}
projects / bcachefs-tools-debian / blobdiff