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direct-io: merge direct_io_walker into __blockdev_direct_IO
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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>
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Andi Kleen authored and root committed Oct 28, 2011
1 parent ba253fb commit 847cc63
Showing 1 changed file with 132 additions and 139 deletions.
271 changes: 132 additions & 139 deletions fs/direct-io.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1043,136 +1043,10 @@ static int do_direct_IO(struct dio *dio, struct dio_submit *sdio,
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
Expand All @@ -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;
}

/*
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;
Expand Down

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