From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751840Ab2IGPdh (ORCPT ); Fri, 7 Sep 2012 11:33:37 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:52113 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751836Ab2IGPbI (ORCPT ); Fri, 7 Sep 2012 11:31:08 -0400 From: Paolo Bonzini To: linux-kernel@vger.kernel.org Cc: target-devel@vger.kernel.org, nab@linux-iscsi.org, hch@lst.de, roland@kernel.org Subject: [PATCH 04/11] target: support zero-size allocation lengths in transport_kmap_data_sg Date: Fri, 7 Sep 2012 17:30:35 +0200 Message-Id: <1347031842-2531-5-git-send-email-pbonzini@redhat.com> X-Mailer: git-send-email 1.7.11.2 In-Reply-To: <1347031842-2531-1-git-send-email-pbonzini@redhat.com> References: <1347031842-2531-1-git-send-email-pbonzini@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In order to support zero-size allocation lengths, do not assert that we have a scatterlist until after checking cmd->data_length. But once we do this, we can have two cases of transport_kmap_data_sg returning NULL: a zero-size allocation length, or an out-of-memory condition. Report the latter using sense codes, so that the SCSI command that triggered it will fail. Signed-off-by: Paolo Bonzini --- drivers/target/target_core_transport.c | 13 +++++++++---- 1 files changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 2e55aa9..8facb74 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -2185,7 +2185,6 @@ void *transport_kmap_data_sg(struct se_cmd *cmd) struct page **pages; int i; - BUG_ON(!sg); /* * We need to take into account a possible offset here for fabrics like * tcm_loop who may be using a contig buffer from the SCSI midlayer for @@ -2193,13 +2192,17 @@ void *transport_kmap_data_sg(struct se_cmd *cmd) */ if (!cmd->t_data_nents) return NULL; - else if (cmd->t_data_nents == 1) + + BUG_ON(!sg); + if (cmd->t_data_nents == 1) return kmap(sg_page(sg)) + sg->offset; /* >1 page. use vmap */ pages = kmalloc(sizeof(*pages) * cmd->t_data_nents, GFP_KERNEL); - if (!pages) + if (!pages) { + cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; return NULL; + } /* convert sg[] to pages[] */ for_each_sg(cmd->t_data_sg, sg, cmd->t_data_nents, i) { @@ -2208,8 +2211,10 @@ void *transport_kmap_data_sg(struct se_cmd *cmd) cmd->t_data_vmap = vmap(pages, cmd->t_data_nents, VM_MAP, PAGE_KERNEL); kfree(pages); - if (!cmd->t_data_vmap) + if (!cmd->t_data_vmap) { + cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; return NULL; + } return cmd->t_data_vmap + cmd->t_data_sg[0].offset; } -- 1.7.1