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authorPaolo Bonzini <pbonzini@redhat.com>2012-09-07 17:30:35 +0200
committerNicholas Bellinger <nab@linux-iscsi.org>2012-09-07 11:10:32 -0700
commit3717ef0c63e90686d959158e9728a13a49229be6 (patch)
tree2533871c52a5b22e1471443f972850afcfe480b6 /drivers/target
parent9b16b9edb4fd0dc86ee0fbe1f7ede580e26e85f4 (diff)
downloadlinux-3717ef0c63e90686d959158e9728a13a49229be6.tar.bz2
target: support zero-size allocation lengths in transport_kmap_data_sg
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 <pbonzini@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target')
-rw-r--r--drivers/target/target_core_transport.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 7ddb0c33f644..4403477882b3 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -2190,7 +2190,6 @@ 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
@@ -2198,13 +2197,17 @@ 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) {
@@ -2213,8 +2216,10 @@ 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;
}