Doug / smarc-fsl-linux-kernel

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Commit fb199746303a6bfd6121834ec9e810471185c530

Authored by Akinobu Mita
Committed by Jens Axboe
1 parent 2472892a3c
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

block: fix blk_register_queue() return value 

blk_register_queue() returns -ENXIO when queue->request_fn is NULL.  But there
are some block drivers that call blk_register_queue() via add_disk() with
queue->request_fn == NULL.  (For example, brd, loop)

Although no one checks return value of blk_register_queue(), this patch makes
it return 0 instead of -ENXIO when queue->request_fn is NULL,

Also this patch adds warning when blk_register_queue() and
blk_unregister_queue() are called with queue == NULL rather than ignore
invalid usage silently.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

Showing 1 changed file with 8 additions and 2 deletions Side-by-side Diff

... ... @@ -276,9 +276,12 @@
276 276  
277 277 struct request_queue *q = disk->queue;
278 278  
279   - if (!q || !q->request_fn)
  279 + if (WARN_ON(!q))
280 280 return -ENXIO;
281 281  
  282 + if (!q->request_fn)
  283 + return 0;
  284 +
282 285 ret = kobject_add(&q->kobj, kobject_get(&disk->dev.kobj),
283 286 "%s", "queue");
284 287 if (ret < 0)
... ... @@ -300,7 +303,10 @@
300 303 {
301 304 struct request_queue *q = disk->queue;
302 305  
303   - if (q && q->request_fn) {
  306 + if (WARN_ON(!q))
  307 + return;
  308 +
  309 + if (q->request_fn) {
304 310 elv_unregister_queue(q);
305 311  
306 312 kobject_uevent(&q->kobj, KOBJ_REMOVE);