direct-io: merge direct_io_walker into __blockdev_direct_IO

This doesn't change anything for the compiler, but hch thought it would
make the code clearer.

I moved the reference counting into its own little inline.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

1 files changed, 132 insertions, 139 deletions

diff --git a/fs/direct-io.c b/fs/direct-io.c
index 6d425821be66..d740ab67ff6e 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -1043,136 +1043,10 @@ out:
         return ret;
 }
 
-static inline ssize_t
-direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode, 
-        const struct iovec *iov, loff_t offset, unsigned long nr_segs, 
-        unsigned blkbits, get_block_t get_block, dio_iodone_t end_io,
-        dio_submit_t submit_io, struct dio *dio, struct dio_submit *sdio)
+static inline int drop_refcount(struct dio *dio)
 {
-        unsigned long user_addr; 
+        int ret2;
         unsigned long flags;
-        int seg;
-        ssize_t ret = 0;
-        ssize_t ret2;
-        size_t bytes;
-        struct buffer_head map_bh = { 0, };
-
-        dio->inode = inode;
-        dio->rw = rw;
-        sdio->blkbits = blkbits;
-        sdio->blkfactor = inode->i_blkbits - blkbits;
-        sdio->block_in_file = offset >> blkbits;
-
-        sdio->get_block = get_block;
-        dio->end_io = end_io;
-        sdio->submit_io = submit_io;
-        sdio->final_block_in_bio = -1;
-        sdio->next_block_for_io = -1;
-
-        dio->iocb = iocb;
-        dio->i_size = i_size_read(inode);
-
-        spin_lock_init(&dio->bio_lock);
-        dio->refcount = 1;
-
-        /*
-         * In case of non-aligned buffers, we may need 2 more
-         * pages since we need to zero out first and last block.
-         */
-        if (unlikely(sdio->blkfactor))
-                sdio->pages_in_io = 2;
-
-        for (seg = 0; seg < nr_segs; seg++) {
-                user_addr = (unsigned long)iov[seg].iov_base;
-                sdio->pages_in_io +=
-                        ((user_addr+iov[seg].iov_len +PAGE_SIZE-1)/PAGE_SIZE
-                                - user_addr/PAGE_SIZE);
-        }
-
-        for (seg = 0; seg < nr_segs; seg++) {
-                user_addr = (unsigned long)iov[seg].iov_base;
-                sdio->size += bytes = iov[seg].iov_len;
-
-                /* Index into the first page of the first block */
-                sdio->first_block_in_page = (user_addr & ~PAGE_MASK) >> blkbits;
-                sdio->final_block_in_request = sdio->block_in_file +
-                                                (bytes >> blkbits);
-                /* Page fetching state */
-                sdio->head = 0;
-                sdio->tail = 0;
-                sdio->curr_page = 0;
-
-                sdio->total_pages = 0;
-                if (user_addr & (PAGE_SIZE-1)) {
-                        sdio->total_pages++;
-                        bytes -= PAGE_SIZE - (user_addr & (PAGE_SIZE - 1));
-                }
-                sdio->total_pages += (bytes + PAGE_SIZE - 1) / PAGE_SIZE;
-                sdio->curr_user_address = user_addr;
-        
-                ret = do_direct_IO(dio, sdio, &map_bh);
-
-                dio->result += iov[seg].iov_len -
-                        ((sdio->final_block_in_request - sdio->block_in_file) <<
-                                        blkbits);
-
-                if (ret) {
-                        dio_cleanup(dio, sdio);
-                        break;
-                }
-        } /* end iovec loop */
-
-        if (ret == -ENOTBLK) {
-                /*
-                 * The remaining part of the request will be
-                 * be handled by buffered I/O when we return
-                 */
-                ret = 0;
-        }
-        /*
-         * There may be some unwritten disk at the end of a part-written
-         * fs-block-sized block.  Go zero that now.
-         */
-        dio_zero_block(dio, sdio, 1, &map_bh);
-
-        if (sdio->cur_page) {
-                ret2 = dio_send_cur_page(dio, sdio, &map_bh);
-                if (ret == 0)
-                        ret = ret2;
-                page_cache_release(sdio->cur_page);
-                sdio->cur_page = NULL;
-        }
-        if (sdio->bio)
-                dio_bio_submit(dio, sdio);
-
-        /*
-         * It is possible that, we return short IO due to end of file.
-         * In that case, we need to release all the pages we got hold on.
-         */
-        dio_cleanup(dio, sdio);
-
-        /*
-         * All block lookups have been performed. For READ requests
-         * we can let i_mutex go now that its achieved its purpose
-         * of protecting us from looking up uninitialized blocks.
-         */
-        if (rw == READ && (dio->flags & DIO_LOCKING))
-                mutex_unlock(&dio->inode->i_mutex);
-
-        /*
-         * The only time we want to leave bios in flight is when a successful
-         * partial aio read or full aio write have been setup.  In that case
-         * bio completion will call aio_complete.  The only time it's safe to
-         * call aio_complete is when we return -EIOCBQUEUED, so we key on that.
-         * This had *better* be the only place that raises -EIOCBQUEUED.
-         */
-        BUG_ON(ret == -EIOCBQUEUED);
-        if (dio->is_async && ret == 0 && dio->result &&
-            ((rw & READ) || (dio->result == sdio->size)))
-                ret = -EIOCBQUEUED;
-
-        if (ret != -EIOCBQUEUED)
-                dio_await_completion(dio);
 
         /*
          * Sync will always be dropping the final ref and completing the
@@ -1188,14 +1062,7 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode,
         spin_lock_irqsave(&dio->bio_lock, flags);
         ret2 = --dio->refcount;
         spin_unlock_irqrestore(&dio->bio_lock, flags);
-
-        if (ret2 == 0) {
-                ret = dio_complete(dio, offset, ret, false);
-                kmem_cache_free(dio_cache, dio);
-        } else
-                BUG_ON(ret != -EIOCBQUEUED);
-
-        return ret;
+        return ret2;
 }
 
 /*
@@ -1239,6 +1106,9 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
         loff_t end = offset;
         struct dio *dio;
         struct dio_submit sdio = { 0, };
+        unsigned long user_addr;
+        size_t bytes;
+        struct buffer_head map_bh = { 0, };
 
         if (rw & WRITE)
                 rw = WRITE_ODIRECT;
@@ -1316,9 +1186,132 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
         dio->is_async = !is_sync_kiocb(iocb) && !((rw & WRITE) &&
                 (end > i_size_read(inode)));
 
-        retval = direct_io_worker(rw, iocb, inode, iov, offset,
-                                nr_segs, blkbits, get_block, end_io,
-                                  submit_io, dio, &sdio);
+        retval = 0;
+
+        dio->inode = inode;
+        dio->rw = rw;
+        sdio.blkbits = blkbits;
+        sdio.blkfactor = inode->i_blkbits - blkbits;
+        sdio.block_in_file = offset >> blkbits;
+
+        sdio.get_block = get_block;
+        dio->end_io = end_io;
+        sdio.submit_io = submit_io;
+        sdio.final_block_in_bio = -1;
+        sdio.next_block_for_io = -1;
+
+        dio->iocb = iocb;
+        dio->i_size = i_size_read(inode);
+
+        spin_lock_init(&dio->bio_lock);
+        dio->refcount = 1;
+
+        /*
+         * In case of non-aligned buffers, we may need 2 more
+         * pages since we need to zero out first and last block.
+         */
+        if (unlikely(sdio.blkfactor))
+                sdio.pages_in_io = 2;
+
+        for (seg = 0; seg < nr_segs; seg++) {
+                user_addr = (unsigned long)iov[seg].iov_base;
+                sdio.pages_in_io +=
+                        ((user_addr + iov[seg].iov_len + PAGE_SIZE-1) /
+                                PAGE_SIZE - user_addr / PAGE_SIZE);
+        }
+
+        for (seg = 0; seg < nr_segs; seg++) {
+                user_addr = (unsigned long)iov[seg].iov_base;
+                sdio.size += bytes = iov[seg].iov_len;
+
+                /* Index into the first page of the first block */
+                sdio.first_block_in_page = (user_addr & ~PAGE_MASK) >> blkbits;
+                sdio.final_block_in_request = sdio.block_in_file +
+                                                (bytes >> blkbits);
+                /* Page fetching state */
+                sdio.head = 0;
+                sdio.tail = 0;
+                sdio.curr_page = 0;
+
+                sdio.total_pages = 0;
+                if (user_addr & (PAGE_SIZE-1)) {
+                        sdio.total_pages++;
+                        bytes -= PAGE_SIZE - (user_addr & (PAGE_SIZE - 1));
+                }
+                sdio.total_pages += (bytes + PAGE_SIZE - 1) / PAGE_SIZE;
+                sdio.curr_user_address = user_addr;
+
+                retval = do_direct_IO(dio, &sdio, &map_bh);
+
+                dio->result += iov[seg].iov_len -
+                        ((sdio.final_block_in_request - sdio.block_in_file) <<
+                                        blkbits);
+
+                if (retval) {
+                        dio_cleanup(dio, &sdio);
+                        break;
+                }
+        } /* end iovec loop */
+
+        if (retval == -ENOTBLK) {
+                /*
+                 * The remaining part of the request will be
+                 * be handled by buffered I/O when we return
+                 */
+                retval = 0;
+        }
+        /*
+         * There may be some unwritten disk at the end of a part-written
+         * fs-block-sized block.  Go zero that now.
+         */
+        dio_zero_block(dio, &sdio, 1, &map_bh);
+
+        if (sdio.cur_page) {
+                ssize_t ret2;
+
+                ret2 = dio_send_cur_page(dio, &sdio, &map_bh);
+                if (retval == 0)
+                        retval = ret2;
+                page_cache_release(sdio.cur_page);
+                sdio.cur_page = NULL;
+        }
+        if (sdio.bio)
+                dio_bio_submit(dio, &sdio);
+
+        /*
+         * It is possible that, we return short IO due to end of file.
+         * In that case, we need to release all the pages we got hold on.
+         */
+        dio_cleanup(dio, &sdio);
+
+        /*
+         * All block lookups have been performed. For READ requests
+         * we can let i_mutex go now that its achieved its purpose
+         * of protecting us from looking up uninitialized blocks.
+         */
+        if (rw == READ && (dio->flags & DIO_LOCKING))
+                mutex_unlock(&dio->inode->i_mutex);
+
+        /*
+         * The only time we want to leave bios in flight is when a successful
+         * partial aio read or full aio write have been setup.  In that case
+         * bio completion will call aio_complete.  The only time it's safe to
+         * call aio_complete is when we return -EIOCBQUEUED, so we key on that.
+         * This had *better* be the only place that raises -EIOCBQUEUED.
+         */
+        BUG_ON(retval == -EIOCBQUEUED);
+        if (dio->is_async && retval == 0 && dio->result &&
+            ((rw & READ) || (dio->result == sdio.size)))
+                retval = -EIOCBQUEUED;
+
+        if (retval != -EIOCBQUEUED)
+                dio_await_completion(dio);
+
+        if (drop_refcount(dio) == 0) {
+                retval = dio_complete(dio, offset, retval, false);
+                kmem_cache_free(dio_cache, dio);
+        } else
+                BUG_ON(retval != -EIOCBQUEUED);
 
 out:
         return retval;