IB/srp: Use a fake scatterlist for non-SG SCSI commands
Since the SCSI midlayer is moving towards entirely getting rid of
commands with use_sg == 0, we should treat this case as an exception.
Therefore, change the IB SRP initiator to create a fake scatterlist
for these commands with sg_init_one(). This simplifies the flow of
DMA mapping and unmapping, since SRP can just use dma_map_sg() and
dma_unmap_sg() unconditionally, rather than having to choose between
the dma_{map,unmap}_sg() and dma_{map,unmap}_single() variants.
Signed-off-by: Roland Dreier <rolandd@cisco.com>
This commit is contained in:
Roland Dreier
Родитель
6f633c8d69
Коммит
cf368713a3
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@ -503,8 +503,10 @@ err:
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static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_target_port *target,
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struct srp_request *req)
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{
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struct scatterlist *scat;
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struct srp_cmd *cmd = req->cmd->buf;
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int len;
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int len, nents, count;
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int i;
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u8 fmt;
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if (!scmnd->request_buffer || scmnd->sc_data_direction == DMA_NONE)
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@ -517,82 +519,66 @@ static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_target_port *target,
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return -EINVAL;
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}
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if (scmnd->use_sg) {
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struct scatterlist *scat = scmnd->request_buffer;
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int n;
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int i;
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n = dma_map_sg(target->srp_host->dev->dma_device,
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scat, scmnd->use_sg, scmnd->sc_data_direction);
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if (n == 1) {
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struct srp_direct_buf *buf = (void *) cmd->add_data;
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fmt = SRP_DATA_DESC_DIRECT;
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buf->va = cpu_to_be64(sg_dma_address(scat));
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buf->key = cpu_to_be32(target->srp_host->mr->rkey);
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buf->len = cpu_to_be32(sg_dma_len(scat));
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len = sizeof (struct srp_cmd) +
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sizeof (struct srp_direct_buf);
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} else {
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struct srp_indirect_buf *buf = (void *) cmd->add_data;
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u32 datalen = 0;
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fmt = SRP_DATA_DESC_INDIRECT;
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if (scmnd->sc_data_direction == DMA_TO_DEVICE)
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cmd->data_out_desc_cnt = n;
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else
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cmd->data_in_desc_cnt = n;
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buf->table_desc.va = cpu_to_be64(req->cmd->dma +
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sizeof *cmd +
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sizeof *buf);
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buf->table_desc.key =
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cpu_to_be32(target->srp_host->mr->rkey);
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buf->table_desc.len =
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cpu_to_be32(n * sizeof (struct srp_direct_buf));
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for (i = 0; i < n; ++i) {
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buf->desc_list[i].va = cpu_to_be64(sg_dma_address(&scat[i]));
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buf->desc_list[i].key =
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cpu_to_be32(target->srp_host->mr->rkey);
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buf->desc_list[i].len = cpu_to_be32(sg_dma_len(&scat[i]));
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datalen += sg_dma_len(&scat[i]);
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}
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buf->len = cpu_to_be32(datalen);
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len = sizeof (struct srp_cmd) +
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sizeof (struct srp_indirect_buf) +
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n * sizeof (struct srp_direct_buf);
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}
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/*
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* This handling of non-SG commands can be killed when the
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* SCSI midlayer no longer generates non-SG commands.
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*/
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if (likely(scmnd->use_sg)) {
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nents = scmnd->use_sg;
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scat = scmnd->request_buffer;
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} else {
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nents = 1;
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scat = &req->fake_sg;
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sg_init_one(scat, scmnd->request_buffer, scmnd->request_bufflen);
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}
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count = dma_map_sg(target->srp_host->dev->dma_device, scat, nents,
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scmnd->sc_data_direction);
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if (count == 1) {
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struct srp_direct_buf *buf = (void *) cmd->add_data;
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dma_addr_t dma;
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dma = dma_map_single(target->srp_host->dev->dma_device,
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scmnd->request_buffer, scmnd->request_bufflen,
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scmnd->sc_data_direction);
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if (dma_mapping_error(dma)) {
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printk(KERN_WARNING PFX "unable to map %p/%d (dir %d)\n",
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scmnd->request_buffer, (int) scmnd->request_bufflen,
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scmnd->sc_data_direction);
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return -EINVAL;
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}
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pci_unmap_addr_set(req, direct_mapping, dma);
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buf->va = cpu_to_be64(dma);
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buf->key = cpu_to_be32(target->srp_host->mr->rkey);
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buf->len = cpu_to_be32(scmnd->request_bufflen);
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fmt = SRP_DATA_DESC_DIRECT;
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len = sizeof (struct srp_cmd) + sizeof (struct srp_direct_buf);
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buf->va = cpu_to_be64(sg_dma_address(scat));
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buf->key = cpu_to_be32(target->srp_host->mr->rkey);
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buf->len = cpu_to_be32(sg_dma_len(scat));
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len = sizeof (struct srp_cmd) +
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sizeof (struct srp_direct_buf);
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} else {
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struct srp_indirect_buf *buf = (void *) cmd->add_data;
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u32 datalen = 0;
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fmt = SRP_DATA_DESC_INDIRECT;
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if (scmnd->sc_data_direction == DMA_TO_DEVICE)
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cmd->data_out_desc_cnt = count;
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else
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cmd->data_in_desc_cnt = count;
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buf->table_desc.va = cpu_to_be64(req->cmd->dma +
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sizeof *cmd +
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sizeof *buf);
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buf->table_desc.key =
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cpu_to_be32(target->srp_host->mr->rkey);
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buf->table_desc.len =
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cpu_to_be32(count * sizeof (struct srp_direct_buf));
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for (i = 0; i < count; ++i) {
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buf->desc_list[i].va = cpu_to_be64(sg_dma_address(&scat[i]));
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buf->desc_list[i].key =
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cpu_to_be32(target->srp_host->mr->rkey);
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buf->desc_list[i].len = cpu_to_be32(sg_dma_len(&scat[i]));
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datalen += sg_dma_len(&scat[i]);
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}
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buf->len = cpu_to_be32(datalen);
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len = sizeof (struct srp_cmd) +
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sizeof (struct srp_indirect_buf) +
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count * sizeof (struct srp_direct_buf);
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}
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if (scmnd->sc_data_direction == DMA_TO_DEVICE)
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@ -600,7 +586,6 @@ static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_target_port *target,
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else
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cmd->buf_fmt = fmt;
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return len;
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}
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@ -608,20 +593,28 @@ static void srp_unmap_data(struct scsi_cmnd *scmnd,
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struct srp_target_port *target,
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struct srp_request *req)
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{
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struct scatterlist *scat;
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int nents;
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if (!scmnd->request_buffer ||
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(scmnd->sc_data_direction != DMA_TO_DEVICE &&
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scmnd->sc_data_direction != DMA_FROM_DEVICE))
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return;
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return;
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if (scmnd->use_sg)
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dma_unmap_sg(target->srp_host->dev->dma_device,
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(struct scatterlist *) scmnd->request_buffer,
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scmnd->use_sg, scmnd->sc_data_direction);
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else
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dma_unmap_single(target->srp_host->dev->dma_device,
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pci_unmap_addr(req, direct_mapping),
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scmnd->request_bufflen,
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scmnd->sc_data_direction);
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/*
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* This handling of non-SG commands can be killed when the
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* SCSI midlayer no longer generates non-SG commands.
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*/
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if (likely(scmnd->use_sg)) {
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nents = scmnd->use_sg;
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scat = (struct scatterlist *) scmnd->request_buffer;
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} else {
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nents = 1;
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scat = (struct scatterlist *) scmnd->request_buffer;
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}
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dma_unmap_sg(target->srp_host->dev->dma_device, scat, nents,
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scmnd->sc_data_direction);
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}
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static void srp_process_rsp(struct srp_target_port *target, struct srp_rsp *rsp)
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@ -38,6 +38,7 @@
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#include <linux/types.h>
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#include <linux/list.h>
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#include <linux/mutex.h>
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#include <linux/scatterlist.h>
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#include <scsi/scsi_host.h>
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#include <scsi/scsi_cmnd.h>
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@ -94,7 +95,11 @@ struct srp_request {
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struct scsi_cmnd *scmnd;
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struct srp_iu *cmd;
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struct srp_iu *tsk_mgmt;
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DECLARE_PCI_UNMAP_ADDR(direct_mapping)
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/*
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* Fake scatterlist used when scmnd->use_sg==0. Can be killed
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* when the SCSI midlayer no longer generates non-SG commands.
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*/
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struct scatterlist fake_sg;
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struct completion done;
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short next;
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u8 cmd_done;
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