From: FUJITA Tomonori on
Adds the concrete DMA mapping error handling for SCSI drivers on the
queuecommand path.

Signed-off-by: FUJITA Tomonori <fujita.tomonori(a)lab.ntt.co.jp>
Cc: James Bottomley <James.Bottomley(a)suse.de>
---
Documentation/DMA-API-HOWTO.txt | 4 ++++
1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/Documentation/DMA-API-HOWTO.txt b/Documentation/DMA-API-HOWTO.txt
index 93d9087..a38ddad 100644
--- a/Documentation/DMA-API-HOWTO.txt
+++ b/Documentation/DMA-API-HOWTO.txt
@@ -745,6 +745,10 @@ and return NETDEV_TX_OK if the DMA mapping fails on the transmit hook
(ndo_start_xmit). This means that the socket buffer is just dropped in
the failure case.

+SCSI drivers must return SCSI_MLQUEUE_HOST_BUSY if the DMA mapping
+fails in the queuecommand hook. This means that the SCSI subsystem
+passes the command to the driver again later.
+
Closing

This document, and the API itself, would not be in its current
--
1.6.5

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