From: Cyril Bur <cyrilbur@gmail.com>
To: linuxppc-dev@lists.ozlabs.org, linux-mtd@lists.infradead.org
Cc: benh@kernel.crashing.org, stewart@linux.vnet.ibm.com,
dwmw2@infradead.org, rlippert@google.com, alistair@popple.id.au
Subject: [PATCH v2 10/10] mtd: powernv_flash: Use opal_async_wait_response_interruptible()
Date: Mon, 10 Jul 2017 11:31:06 +1000 [thread overview]
Message-ID: <20170710013106.27276-11-cyrilbur@gmail.com> (raw)
In-Reply-To: <20170710013106.27276-1-cyrilbur@gmail.com>
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: Cyril Bur <cyrilbur@gmail.com>
---
drivers/mtd/devices/powernv_flash.c | 28 +++++++++++++++++++++++-----
1 file changed, 23 insertions(+), 5 deletions(-)
diff --git a/drivers/mtd/devices/powernv_flash.c b/drivers/mtd/devices/powernv_flash.c
index d7243b72ba6e..cfa274ba7e40 100644
--- a/drivers/mtd/devices/powernv_flash.c
+++ b/drivers/mtd/devices/powernv_flash.c
@@ -90,16 +90,34 @@ static int powernv_flash_async_op(struct mtd_info *mtd, enum flash_op op,
goto out_success;
if (rc != OPAL_ASYNC_COMPLETION) {
- dev_err(dev, "opal_flash_async_op(op=%d) failed (rc %d)\n",
+ if (rc != OPAL_BUSY)
+ dev_err(dev, "opal_flash_async_op(op=%d) failed (rc %d)\n",
op, rc);
- rc = -EIO;
+ rc = opal_error_code(rc);
goto out;
}
- rc = opal_async_wait_response(token, &msg);
+ rc = opal_async_wait_response_interruptible(token, &msg);
if (rc) {
- dev_err(dev, "opal async wait failed (rc %d)\n", rc);
- rc = -EIO;
+ /*
+ * Awkward, we've been interrupted but we cannot return. If we
+ * do 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.
+ * Future work will introduce a call to tell OPAL to stop
+ * using the buffer.
+ * 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 must report EINTR so that
+ * it doesn't just send us the next chunk, thus defeating the
+ * point of the _interruptible wait.
+ */
+ rc = -EINTR;
+ if (op == FLASH_OP_READ || op == FLASH_OP_WRITE) {
+ if (opal_async_wait_response(token, &msg))
+ dev_err(dev, "opal async wait failed (rc %d)\n", rc);
+ }
goto out;
}
--
2.13.2
next prev parent reply other threads:[~2017-07-10 1:31 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-10 1:30 [PATCH v2 00/10] Allow opal-async waiters to get interrupted Cyril Bur
2017-07-10 1:30 ` [PATCH v2 01/10] mtd: powernv_flash: Use WARN_ON_ONCE() rather than BUG_ON() Cyril Bur
2017-07-10 1:30 ` [PATCH v2 02/10] mtd: powernv_flash: Lock around concurrent access to OPAL Cyril Bur
2017-07-10 1:30 ` [PATCH v2 03/10] mtd: powernv_flash: Don't treat OPAL_SUCCESS as an error Cyril Bur
2017-07-10 1:31 ` [PATCH v2 04/10] mtd: powernv_flash: Remove pointless goto in driver init Cyril Bur
2017-07-10 1:31 ` [PATCH v2 05/10] powerpc/opal: Make __opal_async_{get, release}_token() static Cyril Bur
2017-07-10 1:31 ` [PATCH v2 06/10] powerpc/opal: Rework the opal-async interface Cyril Bur
2017-07-10 1:31 ` [PATCH v2 07/10] powernv/opal-sensor: remove not needed lock Cyril Bur
2017-07-10 1:31 ` [PATCH v2 08/10] powerpc/opal: Add opal_async_wait_response_interruptible() to opal-async Cyril Bur
2017-07-10 14:05 ` David Laight
2017-07-11 0:48 ` Cyril Bur
2017-07-10 1:31 ` [PATCH v2 09/10] powerpc/powernv: Add OPAL_BUSY to opal_error_code() Cyril Bur
2017-07-10 1:31 ` Cyril Bur [this message]
2017-07-11 4:19 ` [PATCH v2 10/10] mtd: powernv_flash: Use opal_async_wait_response_interruptible() kbuild test robot
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