dm io: simplify dec_count and sync_io (97e7cdf1) · Commits · 戴 / test

drivers/md/dm-io.c

+42 −35

Original line number	Diff line number	Diff line
		@@ -33,7 +33,6 @@ struct dm_io_client {
		struct io {
		unsigned long error_bits;
		atomic_t count;
		struct completion *wait;
		struct dm_io_client *client;
		io_notify_fn callback;
		void *context;
		@@ -112,28 +111,27 @@ static void retrieve_io_and_region_from_bio(struct bio bio, struct io *io,
		* We need an io object to keep track of the number of bios that
		* have been dispatched for a particular io.
		---------------------------------------------------------------/
		static void dec_count(struct io *io, unsigned int region, int error)
		static void complete_io(struct io *io)
		{
		if (error)
		set_bit(region, &io->error_bits);
		unsigned long error_bits = io->error_bits;
		io_notify_fn fn = io->callback;
		void *context = io->context;

		if (atomic_dec_and_test(&io->count)) {
		if (io->vma_invalidate_size)
		invalidate_kernel_vmap_range(io->vma_invalidate_address,
		io->vma_invalidate_size);

		if (io->wait)
		complete(io->wait);

		else {
		unsigned long r = io->error_bits;
		io_notify_fn fn = io->callback;
		void *context = io->context;

		mempool_free(io, io->client->pool);
		fn(r, context);
		}
		fn(error_bits, context);
		}

		static void dec_count(struct io *io, unsigned int region, int error)
		{
		if (error)
		set_bit(region, &io->error_bits);

		if (atomic_dec_and_test(&io->count))
		complete_io(io);
		}

		static void endio(struct bio *bio, int error)
		@@ -376,41 +374,51 @@ static void dispatch_io(int rw, unsigned int num_regions,
		dec_count(io, 0, 0);
		}

		struct sync_io {
		unsigned long error_bits;
		struct completion wait;
		};

		static void sync_io_complete(unsigned long error, void *context)
		{
		struct sync_io *sio = context;

		sio->error_bits = error;
		complete(&sio->wait);
		}

		static int sync_io(struct dm_io_client *client, unsigned int num_regions,
		struct dm_io_region where, int rw, struct dpages dp,
		unsigned long *error_bits)
		{
		/*
		* gcc <= 4.3 can't do the alignment for stack variables, so we must
		* align it on our own.
		* volatile prevents the optimizer from removing or reusing
		* "io_" field from the stack frame (allowed in ANSI C).
		*/
		volatile char io_[sizeof(struct io) + __alignof__(struct io) - 1];
		struct io io = (struct io )PTR_ALIGN(&io_, __alignof__(struct io));
		DECLARE_COMPLETION_ONSTACK(wait);
		struct io *io;
		struct sync_io sio;

		if (num_regions > 1 && (rw & RW_MASK) != WRITE) {
		WARN_ON(1);
		return -EIO;
		}

		init_completion(&sio.wait);

		io = mempool_alloc(client->pool, GFP_NOIO);
		io->error_bits = 0;
		atomic_set(&io->count, 1); /* see dispatch_io() */
		io->wait = &wait;
		io->client = client;
		io->callback = sync_io_complete;
		io->context = &sio;

		io->vma_invalidate_address = dp->vma_invalidate_address;
		io->vma_invalidate_size = dp->vma_invalidate_size;

		dispatch_io(rw, num_regions, where, dp, io, 1);

		wait_for_completion_io(&wait);
		wait_for_completion_io(&sio.wait);

		if (error_bits)
		*error_bits = io->error_bits;
		*error_bits = sio.error_bits;

		return io->error_bits ? -EIO : 0;
		return sio.error_bits ? -EIO : 0;
		}

		static int async_io(struct dm_io_client *client, unsigned int num_regions,
		@@ -428,7 +436,6 @@ static int async_io(struct dm_io_client *client, unsigned int num_regions,
		io = mempool_alloc(client->pool, GFP_NOIO);
		io->error_bits = 0;
		atomic_set(&io->count, 1); /* see dispatch_io() */
		io->wait = NULL;
		io->client = client;
		io->callback = fn;
		io->context = context;
		@@ -481,9 +488,9 @@ static int dp_init(struct dm_io_request io_req, struct dpages dp,
		* New collapsed (a)synchronous interface.
		*
		* If the IO is asynchronous (i.e. it has notify.fn), you must either unplug
		* the queue with blk_unplug() some time later or set REQ_SYNC in
		io_req->bi_rw. If you fail to do one of these, the IO will be submitted to
		* the disk after q->unplug_delay, which defaults to 3ms in blk-settings.c.
		* the queue with blk_unplug() some time later or set REQ_SYNC in io_req->bi_rw.
		* If you fail to do one of these, the IO will be submitted to the disk after
		* q->unplug_delay, which defaults to 3ms in blk-settings.c.
		*/
		int dm_io(struct dm_io_request *io_req, unsigned num_regions,
		struct dm_io_region where, unsigned long sync_error_bits)

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