Merge commit 'origin/master' into next

[deliverable/linux.git] / drivers / block / loop.c

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index fb06ed6592121fe8dbdfa79da727f2a6eac921f5..bf034557767243ecbb0fd3c56538f7877e222345 100644 (file)
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -392,8 +392,7 @@ lo_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
        struct loop_device *lo = p->lo;
        struct page *page = buf->page;
        sector_t IV;
-       size_t size;
-       int ret;
+       int size, ret;
 
        ret = buf->ops->confirm(pipe, buf);
        if (unlikely(ret))
@@ -623,6 +622,18 @@ static int loop_switch(struct loop_device *lo, struct file *file)
        return 0;
 }
 
+/*
+ * Helper to flush the IOs in loop, but keeping loop thread running
+ */
+static int loop_flush(struct loop_device *lo)
+{
+       /* loop not yet configured, no running thread, nothing to flush */
+       if (!lo->lo_thread)
+               return 0;
+
+       return loop_switch(lo, NULL);
+}
+
 /*
  * Do the actual switch; called from the BIO completion routine
  */
@@ -630,14 +641,20 @@ static void do_loop_switch(struct loop_device *lo, struct switch_request *p)
 {
        struct file *file = p->file;
        struct file *old_file = lo->lo_backing_file;
-       struct address_space *mapping = file->f_mapping;
+       struct address_space *mapping;
+
+       /* if no new file, only flush of queued bios requested */
+       if (!file)
+               goto out;
 
+       mapping = file->f_mapping;
        mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask);
        lo->lo_backing_file = file;
        lo->lo_blocksize = S_ISBLK(mapping->host->i_mode) ?
                mapping->host->i_bdev->bd_block_size : PAGE_SIZE;
        lo->old_gfp_mask = mapping_gfp_mask(mapping);
        mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
+out:
        complete(&p->wait);
 }
 
@@ -901,6 +918,7 @@ static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev)
 
        kthread_stop(lo->lo_thread);
 
+       lo->lo_queue->unplug_fn = NULL;
        lo->lo_backing_file = NULL;
 
        loop_release_xfer(lo);
@@ -1345,11 +1363,25 @@ static int lo_release(struct gendisk *disk, fmode_t mode)
        struct loop_device *lo = disk->private_data;
 
        mutex_lock(&lo->lo_ctl_mutex);
-       --lo->lo_refcnt;
 
-       if ((lo->lo_flags & LO_FLAGS_AUTOCLEAR) && !lo->lo_refcnt)
+       if (--lo->lo_refcnt)
+               goto out;
+
+       if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) {
+               /*
+                * In autoclear mode, stop the loop thread
+                * and remove configuration after last close.
+                */
                loop_clr_fd(lo, NULL);
+       } else {
+               /*
+                * Otherwise keep thread (if running) and config,
+                * but flush possible ongoing bios in thread.
+                */
+               loop_flush(lo);
+       }
 
+out:
        mutex_unlock(&lo->lo_ctl_mutex);
 
        return 0;