fs/block_dev.c: remove #if 0'ed code

Commit b2e895dbd80c420bfc0937c3729b4afe073b3848 #if 0'ed this code stating:

<--  snip  -->

    [PATCH] revert blockdev direct io back to 2.6.19 version

    Andrew Vasquez is reporting as-iosched oopses and a 65% throughput
    slowdown due to the recent special-casing of direct-io against
    blockdevs.  We don't know why either of these things are occurring.

    The patch minimally reverts us back to the 2.6.19 code for a 2.6.20
    release.

<--  snip  -->

It has since been dead code, and unless someone wants to revive it now
it's time to remove it.

This patch also makes bio_release_pages() static again and removes the
ki_bio_count member from struct kiocb, reverting changes that had been
done for this dead code.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Jens Axboe <axboe@carl.home.kernel.dk>

2 files changed, 1 insertions, 198 deletions

diff --git a/fs/bio.c b/fs/bio.c
index 242e409dab4b..3312fcc3c098 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -903,7 +903,7 @@ void bio_set_pages_dirty(struct bio *bio)
         }
 }
 
-void bio_release_pages(struct bio *bio)
+static void bio_release_pages(struct bio *bio)
 {
         struct bio_vec *bvec = bio->bi_io_vec;
         int i;
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 8335f0e1b0fb..7d822fae7765 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -173,203 +173,6 @@ blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
                                 iov, offset, nr_segs, blkdev_get_blocks, NULL);
 }
 
-#if 0
-static void blk_end_aio(struct bio *bio, int error)
-{
-        struct kiocb *iocb = bio->bi_private;
-        atomic_t *bio_count = &iocb->ki_bio_count;
-
-        if (bio_data_dir(bio) == READ)
-                bio_check_pages_dirty(bio);
-        else {
-                bio_release_pages(bio);
-                bio_put(bio);
-        }
-
-        /* iocb->ki_nbytes stores error code from LLDD */
-        if (error)
-                iocb->ki_nbytes = -EIO;
-
-        if (atomic_dec_and_test(bio_count)) {
-                if ((long)iocb->ki_nbytes < 0)
-                        aio_complete(iocb, iocb->ki_nbytes, 0);
-                else
-                        aio_complete(iocb, iocb->ki_left, 0);
-        }
-
-        return 0;
-}
-
-#define VEC_SIZE        16
-struct pvec {
-        unsigned short nr;
-        unsigned short idx;
-        struct page *page[VEC_SIZE];
-};
-
-#define PAGES_SPANNED(addr, len)        \
-        (DIV_ROUND_UP((addr) + (len), PAGE_SIZE) - (addr) / PAGE_SIZE);
-
-/*
- * get page pointer for user addr, we internally cache struct page array for
- * (addr, count) range in pvec to avoid frequent call to get_user_pages.  If
- * internal page list is exhausted, a batch count of up to VEC_SIZE is used
- * to get next set of page struct.
- */
-static struct page *blk_get_page(unsigned long addr, size_t count, int rw,
-                                 struct pvec *pvec)
-{
-        int ret, nr_pages;
-        if (pvec->idx == pvec->nr) {
-                nr_pages = PAGES_SPANNED(addr, count);
-                nr_pages = min(nr_pages, VEC_SIZE);
-                down_read(&current->mm->mmap_sem);
-                ret = get_user_pages(current, current->mm, addr, nr_pages,
-                                     rw == READ, 0, pvec->page, NULL);
-                up_read(&current->mm->mmap_sem);
-                if (ret < 0)
-                        return ERR_PTR(ret);
-                pvec->nr = ret;
-                pvec->idx = 0;
-        }
-        return pvec->page[pvec->idx++];
-}
-
-/* return a page back to pvec array */
-static void blk_unget_page(struct page *page, struct pvec *pvec)
-{
-        pvec->page[--pvec->idx] = page;
-}
-
-static ssize_t
-blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
-                 loff_t pos, unsigned long nr_segs)
-{
-        struct inode *inode = iocb->ki_filp->f_mapping->host;
-        unsigned blkbits = blksize_bits(bdev_hardsect_size(I_BDEV(inode)));
-        unsigned blocksize_mask = (1 << blkbits) - 1;
-        unsigned long seg = 0;  /* iov segment iterator */
-        unsigned long nvec;     /* number of bio vec needed */
-        unsigned long cur_off;  /* offset into current page */
-        unsigned long cur_len;  /* I/O len of current page, up to PAGE_SIZE */
-
-        unsigned long addr;     /* user iovec address */
-        size_t count;           /* user iovec len */
-        size_t nbytes = iocb->ki_nbytes = iocb->ki_left; /* total xfer size */
-        loff_t size;            /* size of block device */
-        struct bio *bio;
-        atomic_t *bio_count = &iocb->ki_bio_count;
-        struct page *page;
-        struct pvec pvec;
-
-        pvec.nr = 0;
-        pvec.idx = 0;
-
-        if (pos & blocksize_mask)
-                return -EINVAL;
-
-        size = i_size_read(inode);
-        if (pos + nbytes > size) {
-                nbytes = size - pos;
-                iocb->ki_left = nbytes;
-        }
-
-        /*
-         * check first non-zero iov alignment, the remaining
-         * iov alignment is checked inside bio loop below.
-         */
-        do {
-                addr = (unsigned long) iov[seg].iov_base;
-                count = min(iov[seg].iov_len, nbytes);
-                if (addr & blocksize_mask || count & blocksize_mask)
-                        return -EINVAL;
-        } while (!count && ++seg < nr_segs);
-        atomic_set(bio_count, 1);
-
-        while (nbytes) {
-                /* roughly estimate number of bio vec needed */
-                nvec = (nbytes + PAGE_SIZE - 1) / PAGE_SIZE;
-                nvec = max(nvec, nr_segs - seg);
-                nvec = min(nvec, (unsigned long) BIO_MAX_PAGES);
-
-                /* bio_alloc should not fail with GFP_KERNEL flag */
-                bio = bio_alloc(GFP_KERNEL, nvec);
-                bio->bi_bdev = I_BDEV(inode);
-                bio->bi_end_io = blk_end_aio;
-                bio->bi_private = iocb;
-                bio->bi_sector = pos >> blkbits;
-same_bio:
-                cur_off = addr & ~PAGE_MASK;
-                cur_len = PAGE_SIZE - cur_off;
-                if (count < cur_len)
-                        cur_len = count;
-
-                page = blk_get_page(addr, count, rw, &pvec);
-                if (unlikely(IS_ERR(page)))
-                        goto backout;
-
-                if (bio_add_page(bio, page, cur_len, cur_off)) {
-                        pos += cur_len;
-                        addr += cur_len;
-                        count -= cur_len;
-                        nbytes -= cur_len;
-
-                        if (count)
-                                goto same_bio;
-                        while (++seg < nr_segs) {
-                                addr = (unsigned long) iov[seg].iov_base;
-                                count = iov[seg].iov_len;
-                                if (!count)
-                                        continue;
-                                if (unlikely(addr & blocksize_mask ||
-                                             count & blocksize_mask)) {
-                                        page = ERR_PTR(-EINVAL);
-                                        goto backout;
-                                }
-                                count = min(count, nbytes);
-                                goto same_bio;
-                        }
-                } else {
-                        blk_unget_page(page, &pvec);
-                }
-
-                /* bio is ready, submit it */
-                if (rw == READ)
-                        bio_set_pages_dirty(bio);
-                atomic_inc(bio_count);
-                submit_bio(rw, bio);
-        }
-
-completion:
-        iocb->ki_left -= nbytes;
-        nbytes = iocb->ki_left;
-        iocb->ki_pos += nbytes;
-
-        blk_run_address_space(inode->i_mapping);
-        if (atomic_dec_and_test(bio_count))
-                aio_complete(iocb, nbytes, 0);
-
-        return -EIOCBQUEUED;
-
-backout:
-        /*
-         * back out nbytes count constructed so far for this bio,
-         * we will throw away current bio.
-         */
-        nbytes += bio->bi_size;
-        bio_release_pages(bio);
-        bio_put(bio);
-
-        /*
-         * if no bio was submmitted, return the error code.
-         * otherwise, proceed with pending I/O completion.
-         */
-        if (atomic_read(bio_count) == 1)
-                return PTR_ERR(page);
-        goto completion;
-}
-#endif
-
 static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
 {
         return block_write_full_page(page, blkdev_get_block, wbc);