loop: split loop_lookup

loop_lookup has two callers - one wants to do the a find by index and the
other wants any unbound loop device.  Open code the respective
functionality in each caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210623145908.92973-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index b217065..ff70146 100644 (file)
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -2353,44 +2353,6 @@ static void loop_remove(struct loop_device *lo)
        kfree(lo);
 }
 
-static int find_free_cb(int id, void *ptr, void *data)
-{
-       struct loop_device *lo = ptr;
-       struct loop_device **l = data;
-
-       if (lo->lo_state == Lo_unbound) {
-               *l = lo;
-               return 1;
-       }
-       return 0;
-}
-
-static int loop_lookup(struct loop_device **l, int i)
-{
-       struct loop_device *lo;
-       int ret = -ENODEV;
-
-       if (i < 0) {
-               int err;
-
-               err = idr_for_each(&loop_index_idr, &find_free_cb, &lo);
-               if (err == 1) {
-                       *l = lo;
-                       ret = lo->lo_number;
-               }
-               goto out;
-       }
-
-       /* lookup and return a specific i */
-       lo = idr_find(&loop_index_idr, i);
-       if (lo) {
-               *l = lo;
-               ret = lo->lo_number;
-       }
-out:
-       return ret;
-}
-
 static void loop_probe(dev_t dev)
 {
        int idx = MINOR(dev) >> part_shift;
@@ -2414,9 +2376,11 @@ static int loop_control_remove(int idx)
        if (ret)
                return ret;
 
-       ret = loop_lookup(&lo, idx);
-       if (ret < 0)
+       lo = idr_find(&loop_index_idr, idx);
+       if (!lo) {
+               ret = -ENODEV;
                goto out_unlock_ctrl;
+       }
 
        ret = mutex_lock_killable(&lo->lo_mutex);
        if (ret)
@@ -2440,17 +2404,20 @@ out_unlock_ctrl:
 static int loop_control_get_free(int idx)
 {
        struct loop_device *lo;
-       int ret;
+       int id, ret;
 
        ret = mutex_lock_killable(&loop_ctl_mutex);
        if (ret)
                return ret;
-       ret = loop_lookup(&lo, -1);
+       idr_for_each_entry(&loop_index_idr, lo, id) {
+               if (lo->lo_state == Lo_unbound)
+                       goto found;
+       }
        mutex_unlock(&loop_ctl_mutex);
-
-       if (ret >= 0)
-               return ret;
        return loop_add(-1);
+found:
+       mutex_unlock(&loop_ctl_mutex);
+       return id;
 }
 
 static long loop_control_ioctl(struct file *file, unsigned int cmd,