From ffe7b0e9326d9c68f5688bef691dd49f1e0d3651 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Fri, 7 Sep 2012 17:30:38 +0200 Subject: [PATCH] target: support zero allocation length in INQUIRY INQUIRY processing already uses an on-heap bounce buffer for loopback, but not for other fabrics. Switch this to a cheaper on-stack bounce buffer, similar to the one used by MODE SENSE and REQUEST SENSE, and use it unconditionally. With this in place, zero allocation length is handled simply by checking the return address of transport_kmap_data_sg. Testcase: sg_raw /dev/sdb 12 00 83 00 00 00 should fail with ILLEGAL REQUEST / INVALID FIELD IN CDB sense does not fail without the patch fails correctly with the series Signed-off-by: Paolo Bonzini Cc: stable@vger.kernel.org Signed-off-by: Nicholas Bellinger --- drivers/target/target_core_spc.c | 31 ++++++------------------------- 1 file changed, 6 insertions(+), 25 deletions(-) diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c index 388a922c8f6d..b3d8fd260374 100644 --- a/drivers/target/target_core_spc.c +++ b/drivers/target/target_core_spc.c @@ -600,30 +600,11 @@ static int spc_emulate_inquiry(struct se_cmd *cmd) { struct se_device *dev = cmd->se_dev; struct se_portal_group *tpg = cmd->se_lun->lun_sep->sep_tpg; - unsigned char *buf, *map_buf; + unsigned char *rbuf; unsigned char *cdb = cmd->t_task_cdb; + unsigned char buf[SE_INQUIRY_BUF]; int p, ret; - map_buf = transport_kmap_data_sg(cmd); - /* - * If SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC is not set, then we - * know we actually allocated a full page. Otherwise, if the - * data buffer is too small, allocate a temporary buffer so we - * don't have to worry about overruns in all our INQUIRY - * emulation handling. - */ - if (cmd->data_length < SE_INQUIRY_BUF && - (cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC)) { - buf = kzalloc(SE_INQUIRY_BUF, GFP_KERNEL); - if (!buf) { - transport_kunmap_data_sg(cmd); - cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; - return -ENOMEM; - } - } else { - buf = map_buf; - } - if (dev == tpg->tpg_virt_lun0.lun_se_dev) buf[0] = 0x3f; /* Not connected */ else @@ -655,11 +636,11 @@ static int spc_emulate_inquiry(struct se_cmd *cmd) ret = -EINVAL; out: - if (buf != map_buf) { - memcpy(map_buf, buf, cmd->data_length); - kfree(buf); + rbuf = transport_kmap_data_sg(cmd); + if (rbuf) { + memcpy(rbuf, buf, min_t(u32, sizeof(buf), cmd->data_length)); + transport_kunmap_data_sg(cmd); } - transport_kunmap_data_sg(cmd); if (!ret) target_complete_cmd(cmd, GOOD); -- 2.34.1