#include <linux/fs.h>
#include <linux/vmalloc.h>
#include <linux/miscdevice.h>
+#include <linux/blk_types.h>
+#include <linux/bio.h>
#include <asm/unaligned.h>
#include <scsi/scsi_common.h>
#include <scsi/scsi_proto.h>
u32 tvc_prot_sgl_count;
/* Saved unpacked SCSI LUN for vhost_scsi_target_queue_cmd() */
u32 tvc_lun;
+ u32 copied_iov:1;
+ const void *saved_iter_addr;
+ struct iov_iter saved_iter;
/* Pointer to the SGL formatted memory from virtio-scsi */
struct scatterlist *tvc_sgl;
struct scatterlist *tvc_prot_sgl;
int i;
if (tv_cmd->tvc_sgl_count) {
- for (i = 0; i < tv_cmd->tvc_sgl_count; i++)
- put_page(sg_page(&tv_cmd->tvc_sgl[i]));
+ for (i = 0; i < tv_cmd->tvc_sgl_count; i++) {
+ if (tv_cmd->copied_iov)
+ __free_page(sg_page(&tv_cmd->tvc_sgl[i]));
+ else
+ put_page(sg_page(&tv_cmd->tvc_sgl[i]));
+ }
+ kfree(tv_cmd->saved_iter_addr);
}
if (tv_cmd->tvc_prot_sgl_count) {
for (i = 0; i < tv_cmd->tvc_prot_sgl_count; i++)
mutex_unlock(&vq->mutex);
}
+static int vhost_scsi_copy_sgl_to_iov(struct vhost_scsi_cmd *cmd)
+{
+ struct iov_iter *iter = &cmd->saved_iter;
+ struct scatterlist *sg = cmd->tvc_sgl;
+ struct page *page;
+ size_t len;
+ int i;
+
+ for (i = 0; i < cmd->tvc_sgl_count; i++) {
+ page = sg_page(&sg[i]);
+ len = sg[i].length;
+
+ if (copy_page_to_iter(page, 0, len, iter) != len) {
+ pr_err("Could not copy data while handling misaligned cmd. Error %zu\n",
+ len);
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
/* Fill in status and signal that we are done processing this command
*
* This is scheduled in the vhost work queue so we are called with the owner
pr_debug("%s tv_cmd %p resid %u status %#02x\n", __func__,
cmd, se_cmd->residual_count, se_cmd->scsi_status);
-
memset(&v_rsp, 0, sizeof(v_rsp));
- v_rsp.resid = cpu_to_vhost32(cmd->tvc_vq, se_cmd->residual_count);
- /* TODO is status_qualifier field needed? */
- v_rsp.status = se_cmd->scsi_status;
- v_rsp.sense_len = cpu_to_vhost32(cmd->tvc_vq,
- se_cmd->scsi_sense_length);
- memcpy(v_rsp.sense, cmd->tvc_sense_buf,
- se_cmd->scsi_sense_length);
+
+ if (cmd->saved_iter_addr && vhost_scsi_copy_sgl_to_iov(cmd)) {
+ v_rsp.response = VIRTIO_SCSI_S_BAD_TARGET;
+ } else {
+ v_rsp.resid = cpu_to_vhost32(cmd->tvc_vq,
+ se_cmd->residual_count);
+ /* TODO is status_qualifier field needed? */
+ v_rsp.status = se_cmd->scsi_status;
+ v_rsp.sense_len = cpu_to_vhost32(cmd->tvc_vq,
+ se_cmd->scsi_sense_length);
+ memcpy(v_rsp.sense, cmd->tvc_sense_buf,
+ se_cmd->scsi_sense_length);
+ }
iov_iter_init(&iov_iter, ITER_DEST, cmd->tvc_resp_iov,
cmd->tvc_in_iovs, sizeof(v_rsp));
vhost_scsi_map_to_sgl(struct vhost_scsi_cmd *cmd,
struct iov_iter *iter,
struct scatterlist *sgl,
- bool write)
+ bool is_prot)
{
struct page **pages = cmd->tvc_upages;
struct scatterlist *sg = sgl;
- ssize_t bytes;
- size_t offset;
+ ssize_t bytes, mapped_bytes;
+ size_t offset, mapped_offset;
unsigned int npages = 0;
bytes = iov_iter_get_pages2(iter, pages, LONG_MAX,
if (bytes <= 0)
return bytes < 0 ? bytes : -EFAULT;
+ mapped_bytes = bytes;
+ mapped_offset = offset;
+
while (bytes) {
unsigned n = min_t(unsigned, PAGE_SIZE - offset, bytes);
+ /*
+ * The block layer requires bios/requests to be a multiple of
+ * 512 bytes, but Windows can send us vecs that are misaligned.
+ * This can result in bios and later requests with misaligned
+ * sizes if we have to break up a cmd/scatterlist into multiple
+ * bios.
+ *
+ * We currently only break up a command into multiple bios if
+ * we hit the vec/seg limit, so check if our sgl_count is
+ * greater than the max and if a vec in the cmd has a
+ * misaligned offset/size.
+ */
+ if (!is_prot &&
+ (offset & (SECTOR_SIZE - 1) || n & (SECTOR_SIZE - 1)) &&
+ cmd->tvc_sgl_count > BIO_MAX_VECS) {
+ WARN_ONCE(true,
+ "vhost-scsi detected misaligned IO. Performance may be degraded.");
+ goto revert_iter_get_pages;
+ }
+
sg_set_page(sg++, pages[npages++], n, offset);
bytes -= n;
offset = 0;
}
+
return npages;
+
+revert_iter_get_pages:
+ iov_iter_revert(iter, mapped_bytes);
+
+ npages = 0;
+ while (mapped_bytes) {
+ unsigned int n = min_t(unsigned int, PAGE_SIZE - mapped_offset,
+ mapped_bytes);
+
+ put_page(pages[npages++]);
+
+ mapped_bytes -= n;
+ mapped_offset = 0;
+ }
+
+ return -EINVAL;
}
static int
}
static int
-vhost_scsi_iov_to_sgl(struct vhost_scsi_cmd *cmd, bool write,
- struct iov_iter *iter,
- struct scatterlist *sg, int sg_count)
+vhost_scsi_copy_iov_to_sgl(struct vhost_scsi_cmd *cmd, struct iov_iter *iter,
+ struct scatterlist *sg, int sg_count)
+{
+ size_t len = iov_iter_count(iter);
+ unsigned int nbytes = 0;
+ struct page *page;
+ int i;
+
+ if (cmd->tvc_data_direction == DMA_FROM_DEVICE) {
+ cmd->saved_iter_addr = dup_iter(&cmd->saved_iter, iter,
+ GFP_KERNEL);
+ if (!cmd->saved_iter_addr)
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < sg_count; i++) {
+ page = alloc_page(GFP_KERNEL);
+ if (!page) {
+ i--;
+ goto err;
+ }
+
+ nbytes = min_t(unsigned int, PAGE_SIZE, len);
+ sg_set_page(&sg[i], page, nbytes, 0);
+
+ if (cmd->tvc_data_direction == DMA_TO_DEVICE &&
+ copy_page_from_iter(page, 0, nbytes, iter) != nbytes)
+ goto err;
+
+ len -= nbytes;
+ }
+
+ cmd->copied_iov = 1;
+ return 0;
+
+err:
+ pr_err("Could not read %u bytes while handling misaligned cmd\n",
+ nbytes);
+
+ for (; i >= 0; i--)
+ __free_page(sg_page(&sg[i]));
+ kfree(cmd->saved_iter_addr);
+ return -ENOMEM;
+}
+
+static int
+vhost_scsi_iov_to_sgl(struct vhost_scsi_cmd *cmd, struct iov_iter *iter,
+ struct scatterlist *sg, int sg_count, bool is_prot)
{
struct scatterlist *p = sg;
+ size_t revert_bytes;
int ret;
while (iov_iter_count(iter)) {
- ret = vhost_scsi_map_to_sgl(cmd, iter, sg, write);
+ ret = vhost_scsi_map_to_sgl(cmd, iter, sg, is_prot);
if (ret < 0) {
+ revert_bytes = 0;
+
while (p < sg) {
- struct page *page = sg_page(p++);
- if (page)
+ struct page *page = sg_page(p);
+
+ if (page) {
put_page(page);
+ revert_bytes += p->length;
+ }
+ p++;
}
+
+ iov_iter_revert(iter, revert_bytes);
return ret;
}
sg += ret;
}
+
return 0;
}
size_t data_bytes, struct iov_iter *data_iter)
{
int sgl_count, ret;
- bool write = (cmd->tvc_data_direction == DMA_FROM_DEVICE);
if (prot_bytes) {
sgl_count = vhost_scsi_calc_sgls(prot_iter, prot_bytes,
pr_debug("%s prot_sg %p prot_sgl_count %u\n", __func__,
cmd->tvc_prot_sgl, cmd->tvc_prot_sgl_count);
- ret = vhost_scsi_iov_to_sgl(cmd, write, prot_iter,
- cmd->tvc_prot_sgl,
- cmd->tvc_prot_sgl_count);
+ ret = vhost_scsi_iov_to_sgl(cmd, prot_iter, cmd->tvc_prot_sgl,
+ cmd->tvc_prot_sgl_count, true);
if (ret < 0) {
cmd->tvc_prot_sgl_count = 0;
return ret;
pr_debug("%s data_sg %p data_sgl_count %u\n", __func__,
cmd->tvc_sgl, cmd->tvc_sgl_count);
- ret = vhost_scsi_iov_to_sgl(cmd, write, data_iter,
- cmd->tvc_sgl, cmd->tvc_sgl_count);
+ ret = vhost_scsi_iov_to_sgl(cmd, data_iter, cmd->tvc_sgl,
+ cmd->tvc_sgl_count, false);
+ if (ret == -EINVAL) {
+ sg_init_table(cmd->tvc_sgl, cmd->tvc_sgl_count);
+ ret = vhost_scsi_copy_iov_to_sgl(cmd, data_iter, cmd->tvc_sgl,
+ cmd->tvc_sgl_count);
+ }
+
if (ret < 0) {
cmd->tvc_sgl_count = 0;
return ret;
projects / linux-2.6-microblaze.git / blobdiff