Commit b1ad37ef authored by Matthew Wilcox's avatar Matthew Wilcox
Browse files

NVMe: Call put_nvmeq() before calling nvme_submit_sync_cmd() 



We can't have preemption disabled when we call schedule().  Accept the
possibility that we'll get preempted, and it'll cost us some cacheline
bounces.

Signed-off-by: default avatarMatthew Wilcox <matthew.r.wilcox@intel.com>
parent 3c0cf138

drivers/block/nvme.c

+6 −1
Original line number Diff line number Diff line
@@ -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);

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