Re: [PATCH v2 12/14] cxlflash: Cleanup queuecommand()

[Uma Krishnan]

From: "Matthew R. Ochs" 

The queuecommand routine is disorganized where it populates the
private command and also contains some logic/statements that are
not needed given that cxlflash devices do not (and likely never
will) support scatter-gather.

Restructure the code to remove the unnecessary logic and create an
organized flow:

handle state -> DMA map -> populate command -> send command

Signed-off-by: Matthew R. Ochs 


Acked-by: Uma Krishnan 

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[PATCH v2 12/14] cxlflash: Cleanup queuecommand()

[Uma Krishnan]

From: "Matthew R. Ochs" 

The queuecommand routine is disorganized where it populates the
private command and also contains some logic/statements that are
not needed given that cxlflash devices do not (and likely never
will) support scatter-gather.

Restructure the code to remove the unnecessary logic and create an
organized flow:

handle state -> DMA map -> populate command -> send command

Signed-off-by: Matthew R. Ochs 
---
 drivers/scsi/cxlflash/main.c | 50 ++--
 1 file changed, 20 insertions(+), 30 deletions(-)

diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c
index b763699..4e70c9a 100644
--- a/drivers/scsi/cxlflash/main.c
+++ b/drivers/scsi/cxlflash/main.c
@@ -388,11 +388,11 @@ static int cxlflash_queuecommand(struct Scsi_Host *host, 
struct scsi_cmnd *scp)
struct afu *afu = cfg->afu;
struct device *dev = >dev->dev;
struct afu_cmd *cmd = sc_to_afucz(scp);
+   struct scatterlist *sg = scsi_sglist(scp);
u32 port_sel = scp->device->channel + 1;
-   int nseg, i, ncount;
-   struct scatterlist *sg;
+   u16 req_flags = SISL_REQ_FLAGS_SUP_UNDERRUN;
ulong lock_flags;
-   short lflag = 0;
+   int nseg = 0;
int rc = 0;
int kref_got = 0;
 
@@ -435,45 +435,35 @@ static int cxlflash_queuecommand(struct Scsi_Host *host, 
struct scsi_cmnd *scp)
kref_get(>afu->mapcount);
kref_got = 1;
 
-   cmd->rcb.ctx_id = afu->ctx_hndl;
-   cmd->rcb.msi = SISL_MSI_RRQ_UPDATED;
-   cmd->rcb.port_sel = port_sel;
-   cmd->rcb.lun_id = lun_to_lunid(scp->device->lun);
-
-   if (scp->sc_data_direction == DMA_TO_DEVICE)
-   lflag = SISL_REQ_FLAGS_HOST_WRITE;
-   else
-   lflag = SISL_REQ_FLAGS_HOST_READ;
+   if (likely(sg)) {
+   nseg = scsi_dma_map(scp);
+   if (unlikely(nseg < 0)) {
+   dev_err(dev, "%s: Fail DMA map!\n", __func__);
+   rc = SCSI_MLQUEUE_HOST_BUSY;
+   goto out;
+   }
 
-   cmd->rcb.req_flags = (SISL_REQ_FLAGS_PORT_LUN_ID |
- SISL_REQ_FLAGS_SUP_UNDERRUN | lflag);
+   cmd->rcb.data_len = sg_dma_len(sg);
+   cmd->rcb.data_ea = sg_dma_address(sg);
+   }
 
-   /* Stash the scp in the reserved field, for reuse during interrupt */
cmd->rcb.scp = scp;
cmd->parent = afu;
 
-   nseg = scsi_dma_map(scp);
-   if (unlikely(nseg < 0)) {
-   dev_err(dev, "%s: Fail DMA map! nseg=%d\n",
-   __func__, nseg);
-   rc = SCSI_MLQUEUE_HOST_BUSY;
-   goto out;
-   }
+   cmd->rcb.ctx_id = afu->ctx_hndl;
+   cmd->rcb.msi = SISL_MSI_RRQ_UPDATED;
+   cmd->rcb.port_sel = port_sel;
+   cmd->rcb.lun_id = lun_to_lunid(scp->device->lun);
 
-   ncount = scsi_sg_count(scp);
-   scsi_for_each_sg(scp, sg, ncount, i) {
-   cmd->rcb.data_len = sg_dma_len(sg);
-   cmd->rcb.data_ea = sg_dma_address(sg);
-   }
+   if (scp->sc_data_direction == DMA_TO_DEVICE)
+   req_flags |= SISL_REQ_FLAGS_HOST_WRITE;
 
-   /* Copy the CDB from the scsi_cmnd passed in */
+   cmd->rcb.req_flags = req_flags;
memcpy(cmd->rcb.cdb, scp->cmnd, sizeof(cmd->rcb.cdb));
 
-   /* Send the command */
rc = send_cmd(afu, cmd);
if (unlikely(rc))
scsi_dma_unmap(scp);
-
 out:
if (kref_got)
kref_put(>mapcount, afu_unmap);
-- 
2.1.0

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