[PATCH-v3 4/4] vhost/scsi: Add pre-allocation for tv_cmd SGL + upages memory
From: Nicholas Bellinger
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
Cc: Asias He
Cc: Kent Overstreet
Signed-off-by: Nicholas Bellinger
---
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(_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(_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, [i], write);
+ ret =
[PATCH-v3 4/4] vhost/scsi: Add pre-allocation for tv_cmd SGL + upages memory
From: Nicholas Bellinger n...@linux-iscsi.org
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 m...@redhat.com
Cc: Asias He as...@redhat.com
Cc: Kent Overstreet k...@daterainc.com
Signed-off-by: Nicholas Bellinger n...@linux-iscsi.org
---
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,
