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authorNicholas Bellinger <nab@linux-iscsi.org>2012-10-02 14:00:33 -0700
committerNicholas Bellinger <nab@linux-iscsi.org>2012-10-02 14:16:19 -0700
commit944981c7e106af2aa004847e9177497856630980 (patch)
treecc3f3e84f26a13c18adb7b84055147ed9ea45b88 /drivers/target
parent8f9f44f8957b262de717a48269a5ceca36c2b504 (diff)
target: Add control CDB READ payload zero work-around
This patch carries forward a work-around from tcm_loop to target core code to explicitly clear control CDB READ paylods in order to avoid bugs in scsi-generic user-space code for INQUIRY that do not explicitly zero CDB payload memory. (v2: Drop TARGET_SCF_MAP_CLEAR_MEM, and perform the explicit zero of READ memory for all target_submit_cmd_map_sgls users) Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target')
-rw-r--r--drivers/target/target_core_transport.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index d96d9aa3a496..c33baff86aa6 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -1539,6 +1539,27 @@ int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess
if (sgl_count != 0) {
BUG_ON(!sgl);
+ /*
+ * A work-around for tcm_loop as some userspace code via
+ * scsi-generic do not memset their associated read buffers,
+ * so go ahead and do that here for type non-data CDBs. Also
+ * note that this is currently guaranteed to be a single SGL
+ * for this case by target core in target_setup_cmd_from_cdb()
+ * -> transport_generic_cmd_sequencer().
+ */
+ if (!(se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&
+ se_cmd->data_direction == DMA_FROM_DEVICE) {
+ unsigned char *buf = NULL;
+
+ if (sgl)
+ buf = kmap(sg_page(sgl)) + sgl->offset;
+
+ if (buf) {
+ memset(buf, 0, sgl->length);
+ kunmap(sg_page(sgl));
+ }
+ }
+
rc = transport_generic_map_mem_to_cmd(se_cmd, sgl, sgl_count,
sgl_bidi, sgl_bidi_count);
if (rc != 0) {