diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2012-09-07 17:30:35 +0200 |
|---|---|---|
| committer | Nicholas Bellinger <nab@linux-iscsi.org> | 2012-09-07 11:10:32 -0700 |
| commit | 3717ef0c63e90686d959158e9728a13a49229be6 (patch) | |
| tree | 2533871c52a5b22e1471443f972850afcfe480b6 | |
| parent | 9b16b9edb4fd0dc86ee0fbe1f7ede580e26e85f4 (diff) | |
| download | linux-3717ef0c63e90686d959158e9728a13a49229be6.tar.gz linux-3717ef0c63e90686d959158e9728a13a49229be6.tar.bz2 linux-3717ef0c63e90686d959158e9728a13a49229be6.zip | |
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>
| -rw-r--r-- | 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 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; } |