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Commit 6f469b67 authored by Cyril Bur's avatar Cyril Bur Committed by Michael Ellerman
Browse files

mtd: powernv_flash: Use opal_async_wait_response_interruptible() 



The OPAL calls performed in this driver shouldn't be using
opal_async_wait_response() as this performs a wait_event() which, on
long running OPAL calls could result in hung task warnings. wait_event()
prevents timely signal delivery which is also undesirable.

This patch also attempts to quieten down the use of dev_err() when
errors haven't actually occurred and also to return better information up
the stack rather than always -EIO.

Signed-off-by: default avatarCyril Bur <cyrilbur@gmail.com>
Acked-by: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 77adbd22

drivers/mtd/devices/powernv_flash.c

+35 −22
Original line number Diff line number Diff line
@@ -89,33 +89,46 @@ static int powernv_flash_async_op(struct mtd_info *mtd, enum flash_op op, 
		return -EIO;

	}



	if (rc == OPAL_SUCCESS)

		goto out_success;



	if (rc != OPAL_ASYNC_COMPLETION) {

		dev_err(dev, "opal_flash_async_op(op=%d) failed (rc %d)\n",

				op, rc);

		rc = -EIO;

		goto out;

	}



	rc = opal_async_wait_response(token, &msg);

	if (rc == OPAL_ASYNC_COMPLETION) {

		rc = opal_async_wait_response_interruptible(token, &msg);

		if (rc) {

		dev_err(dev, "opal async wait failed (rc %d)\n", rc);

		rc = -EIO;

			/*

			 * If we return the mtd core will free the

			 * buffer we've just passed to OPAL but OPAL

			 * will continue to read or write from that

			 * memory.

			 * It may be tempting to ultimately return 0

			 * if we're doing a read or a write since we

			 * are going to end up waiting until OPAL is

			 * done. However, because the MTD core sends

			 * us the userspace request in chunks, we need

			 * it to know we've been interrupted.

			 */

			rc = -EINTR;

			if (opal_async_wait_response(token, &msg))

				dev_err(dev, "opal_async_wait_response() failed\n");

			goto out;

		}



		rc = opal_get_async_rc(msg);

out_success:

	if (rc == OPAL_SUCCESS) {

		rc = 0;

		if (retlen)

			*retlen = len;

	} else {

		rc = -EIO;

	}



	/*

	 * OPAL does mutual exclusion on the flash, it will return

	 * OPAL_BUSY.

	 * During firmware updates by the service processor OPAL may

	 * be (temporarily) prevented from accessing the flash, in

	 * this case OPAL will also return OPAL_BUSY.

	 * Both cases aren't errors exactly but the flash could have

	 * changed, userspace should be informed.

	 */

	if (rc != OPAL_SUCCESS && rc != OPAL_BUSY)

		dev_err(dev, "opal_flash_async_op(op=%d) failed (rc %d)\n",

				op, rc);



	if (rc == OPAL_SUCCESS && retlen)

		*retlen = len;



	rc = opal_error_code(rc);

out:

	opal_async_release_token(token);

	return rc;