From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> This patch adds support for pre-allocation of per tv_cmd descriptor scatterlist + user-space page pointer memory using se_sess->sess_cmd_map within tcm_vhost_make_nexus() code. This includes sanity checks within vhost_scsi_map_to_sgl() to reject I/O that exceeds these initial hardcoded values, and the necessary cleanup in tcm_vhost_make_nexus() failure path + tcm_vhost_drop_nexus(). v3 changes: - Rebase to v3.11-rc5 code Cc: Michael S. Tsirkin <mst@xxxxxxxxxx> Cc: Asias He <asias@xxxxxxxxxx> Cc: Kent Overstreet <kmo@xxxxxxxxxxxxx> Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> --- drivers/vhost/scsi.c | 99 ++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 80 insertions(+), 19 deletions(-) diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index af178b7..8e8788e 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -56,6 +56,8 @@ #define TCM_VHOST_NAMELEN 256 #define TCM_VHOST_MAX_CDB_SIZE 32 #define TCM_VHOST_DEFAULT_TAGS 256 +#define TCM_VHOST_PREALLOC_SGLS 2048 +#define TCM_VHOST_PREALLOC_PAGES 2048 struct vhost_scsi_inflight { /* Wait for the flush operation to finish */ @@ -81,6 +83,7 @@ struct tcm_vhost_cmd { u32 tvc_lun; /* Pointer to the SGL formatted memory from virtio-scsi */ struct scatterlist *tvc_sgl; + struct page **tvc_upages; /* Pointer to response */ struct virtio_scsi_cmd_resp __user *tvc_resp; /* Pointer to vhost_scsi for our device */ @@ -458,8 +461,6 @@ static void tcm_vhost_release_cmd(struct se_cmd *se_cmd) u32 i; for (i = 0; i < tv_cmd->tvc_sgl_count; i++) put_page(sg_page(&tv_cmd->tvc_sgl[i])); - - kfree(tv_cmd->tvc_sgl); } tcm_vhost_put_inflight(tv_cmd->inflight); @@ -716,6 +717,8 @@ vhost_scsi_get_tag(struct vhost_virtqueue *vq, struct tcm_vhost_cmd *cmd; struct tcm_vhost_nexus *tv_nexus; struct se_session *se_sess; + struct scatterlist *sg; + struct page **pages; int tag; tv_nexus = tpg->tpg_nexus; @@ -727,8 +730,12 @@ vhost_scsi_get_tag(struct vhost_virtqueue *vq, tag = percpu_ida_alloc(&se_sess->sess_tag_pool, GFP_KERNEL); cmd = &((struct tcm_vhost_cmd *)se_sess->sess_cmd_map)[tag]; + sg = cmd->tvc_sgl; + pages = cmd->tvc_upages; memset(cmd, 0, sizeof(struct tcm_vhost_cmd)); + cmd->tvc_sgl = sg; + cmd->tvc_upages = pages; cmd->tvc_se_cmd.map_tag = tag; cmd->tvc_tag = v_req->tag; cmd->tvc_task_attr = v_req->task_attr; @@ -746,7 +753,8 @@ vhost_scsi_get_tag(struct vhost_virtqueue *vq, * Returns the number of scatterlist entries used or -errno on error. */ static int -vhost_scsi_map_to_sgl(struct scatterlist *sgl, +vhost_scsi_map_to_sgl(struct tcm_vhost_cmd *tv_cmd, + struct scatterlist *sgl, unsigned int sgl_count, struct iovec *iov, int write) @@ -758,13 +766,25 @@ vhost_scsi_map_to_sgl(struct scatterlist *sgl, struct page **pages; int ret, i; + if (sgl_count > TCM_VHOST_PREALLOC_SGLS) { + pr_err("vhost_scsi_map_to_sgl() psgl_count: %u greater than" + " preallocated TCM_VHOST_PREALLOC_SGLS: %u\n", + sgl_count, TCM_VHOST_PREALLOC_SGLS); + return -ENOBUFS; + } + pages_nr = iov_num_pages(iov); if (pages_nr > sgl_count) return -ENOBUFS; - pages = kmalloc(pages_nr * sizeof(struct page *), GFP_KERNEL); - if (!pages) - return -ENOMEM; + if (pages_nr > TCM_VHOST_PREALLOC_PAGES) { + pr_err("vhost_scsi_map_to_sgl() pages_nr: %u greater than" + " preallocated TCM_VHOST_PREALLOC_PAGES: %u\n", + pages_nr, TCM_VHOST_PREALLOC_PAGES); + return -ENOBUFS; + } + + pages = tv_cmd->tvc_upages; ret = get_user_pages_fast((unsigned long)ptr, pages_nr, write, pages); /* No pages were pinned */ @@ -789,7 +809,6 @@ vhost_scsi_map_to_sgl(struct scatterlist *sgl, } out: - kfree(pages); return ret; } @@ -813,24 +832,20 @@ vhost_scsi_map_iov_to_sgl(struct tcm_vhost_cmd *cmd, /* TODO overflow checking */ - sg = kmalloc(sizeof(cmd->tvc_sgl[0]) * sgl_count, GFP_ATOMIC); - if (!sg) - return -ENOMEM; - pr_debug("%s sg %p sgl_count %u is_err %d\n", __func__, - sg, sgl_count, !sg); + sg = cmd->tvc_sgl; + pr_debug("%s sg %p sgl_count %u\n", __func__, sg, sgl_count); sg_init_table(sg, sgl_count); - cmd->tvc_sgl = sg; cmd->tvc_sgl_count = sgl_count; pr_debug("Mapping %u iovecs for %u pages\n", niov, sgl_count); for (i = 0; i < niov; i++) { - ret = vhost_scsi_map_to_sgl(sg, sgl_count, &iov[i], write); + ret = vhost_scsi_map_to_sgl(cmd, sg, sgl_count, &iov[i], + write); if (ret < 0) { for (i = 0; i < cmd->tvc_sgl_count; i++) put_page(sg_page(&cmd->tvc_sgl[i])); - kfree(cmd->tvc_sgl); - cmd->tvc_sgl = NULL; + cmd->tvc_sgl_count = 0; return ret; } @@ -1660,11 +1675,31 @@ static void tcm_vhost_drop_nodeacl(struct se_node_acl *se_acl) kfree(nacl); } +static void tcm_vhost_free_cmd_map_res(struct tcm_vhost_nexus *nexus, + struct se_session *se_sess) +{ + struct tcm_vhost_cmd *tv_cmd; + unsigned int i; + + if (!se_sess->sess_cmd_map) + return; + + for (i = 0; i < TCM_VHOST_DEFAULT_TAGS; i++) { + tv_cmd = &((struct tcm_vhost_cmd *)se_sess->sess_cmd_map)[i]; + + kfree(tv_cmd->tvc_sgl); + kfree(tv_cmd->tvc_upages); + } +} + static int tcm_vhost_make_nexus(struct tcm_vhost_tpg *tpg, const char *name) { struct se_portal_group *se_tpg; + struct se_session *se_sess; struct tcm_vhost_nexus *tv_nexus; + struct tcm_vhost_cmd *tv_cmd; + unsigned int i; mutex_lock(&tpg->tv_tpg_mutex); if (tpg->tpg_nexus) { @@ -1692,6 +1727,26 @@ static int tcm_vhost_make_nexus(struct tcm_vhost_tpg *tpg, kfree(tv_nexus); return -ENOMEM; } + se_sess = tv_nexus->tvn_se_sess; + for (i = 0; i < TCM_VHOST_DEFAULT_TAGS; i++) { + tv_cmd = &((struct tcm_vhost_cmd *)se_sess->sess_cmd_map)[i]; + + tv_cmd->tvc_sgl = kzalloc(sizeof(struct scatterlist) * + TCM_VHOST_PREALLOC_SGLS, GFP_KERNEL); + if (!tv_cmd->tvc_sgl) { + mutex_unlock(&tpg->tv_tpg_mutex); + pr_err("Unable to allocate tv_cmd->tvc_sgl\n"); + goto out; + } + + tv_cmd->tvc_upages = kzalloc(sizeof(struct page *) * + TCM_VHOST_PREALLOC_PAGES, GFP_KERNEL); + if (!tv_cmd->tvc_upages) { + mutex_unlock(&tpg->tv_tpg_mutex); + pr_err("Unable to allocate tv_cmd->tvc_upages\n"); + goto out; + } + } /* * Since we are running in 'demo mode' this call with generate a * struct se_node_acl for the tcm_vhost struct se_portal_group with @@ -1703,9 +1758,7 @@ static int tcm_vhost_make_nexus(struct tcm_vhost_tpg *tpg, mutex_unlock(&tpg->tv_tpg_mutex); pr_debug("core_tpg_check_initiator_node_acl() failed" " for %s\n", name); - transport_free_session(tv_nexus->tvn_se_sess); - kfree(tv_nexus); - return -ENOMEM; + goto out; } /* * Now register the TCM vhost virtual I_T Nexus as active with the @@ -1717,6 +1770,12 @@ static int tcm_vhost_make_nexus(struct tcm_vhost_tpg *tpg, mutex_unlock(&tpg->tv_tpg_mutex); return 0; + +out: + tcm_vhost_free_cmd_map_res(tv_nexus, se_sess); + transport_free_session(se_sess); + kfree(tv_nexus); + return -ENOMEM; } static int tcm_vhost_drop_nexus(struct tcm_vhost_tpg *tpg) @@ -1756,6 +1815,8 @@ static int tcm_vhost_drop_nexus(struct tcm_vhost_tpg *tpg) pr_debug("TCM_vhost_ConfigFS: Removing I_T Nexus to emulated" " %s Initiator Port: %s\n", tcm_vhost_dump_proto_id(tpg->tport), tv_nexus->tvn_se_sess->se_node_acl->initiatorname); + + tcm_vhost_free_cmd_map_res(tv_nexus, se_sess); /* * Release the SCSI I_T Nexus to the emulated vhost Target Port */ -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html