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yaml --- r: 286246 b: refs/heads/master c: b1ad37e h: refs/heads/master v: v3
git-mirror · Nov 4, 2011 · e302af5 · e302af5
1 parent 2ec265b
commit e302af5
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Showing 2 changed files with 7 additions and 2 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 3c0cf138d7789feb3f335f6f1d24ad8fc8b3a23f
+refs/heads/master: b1ad37efcafe396ac3944853589688dd0ec3c64e
diff --git a/trunk/drivers/block/nvme.c b/trunk/drivers/block/nvme.c
@@ -842,8 +842,13 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
 	nvme_setup_prps(&c.common, sg, length);
 
 	nvmeq = get_nvmeq(ns);
-	status = nvme_submit_sync_cmd(nvmeq, &c, &result);
+	/* Since nvme_submit_sync_cmd sleeps, we can't keep preemption
+	 * disabled.  We may be preempted at any point, and be rescheduled
+	 * to a different CPU.  That will cause cacheline bouncing, but no
+	 * additional races since q_lock already protects against other CPUs.
+	 */
 	put_nvmeq(nvmeq);
+	status = nvme_submit_sync_cmd(nvmeq, &c, &result);
 
 	nvme_unmap_user_pages(dev, io.opcode & 1, io.addr, length, sg, nents);
 	put_user(result, &uio->result);