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>

diff --git a/fs/bio.c b/fs/bio.c
index 242e409..3312fcc 100644 (file)
--- 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 8335f0e..7d822fa 100644 (file)
--- 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);

diff --git a/include/linux/aio.h b/include/linux/aio.h
index a9931e2..0d0b7f6 100644 (file)
--- a/include/linux/aio.h
+++ b/include/linux/aio.h
@@ -105,7 +105,6 @@ struct kiocb {
        wait_queue_t            ki_wait;
        loff_t                  ki_pos;
 
-       atomic_t                ki_bio_count;   /* num bio used for this iocb */
        void                    *private;
        /* State that we remember to be able to restart/retry  */
        unsigned short          ki_opcode;

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 4da4413..4c59bdc 100644 (file)
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -326,7 +326,6 @@ extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
                                gfp_t);
 extern void bio_set_pages_dirty(struct bio *bio);
 extern void bio_check_pages_dirty(struct bio *bio);
-extern void bio_release_pages(struct bio *bio);
 extern struct bio *bio_copy_user(struct request_queue *, unsigned long, unsigned int, int);
 extern int bio_uncopy_user(struct bio *);
 void zero_fill_bio(struct bio *bio);