Replace the big fat memset that requires saving and restoring various
fields with just initializing those fields that need initialization.
All the clearing to 0 ismoved to scsi_prepare_cmd as scsi_ioctl_reset
alreadly uses kzalloc to allocate a pre-zeroed command.
This is still conservative and can probably be optimizated further.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
drivers/scsi/scsi_lib.c | 61 ++++++++++++++++++++---------------------
1 file changed, 29 insertions(+), 32 deletions(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index a1c18ba5e8d38..960795d469d8c 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1163,45 +1163,17 @@ static void scsi_cleanup_rq(struct request *rq)
/* Called before a request is prepared. See also scsi_mq_prep_fn(). */
void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
{
- void *buf = cmd->sense_buffer;
- void *prot = cmd->prot_sdb;
struct request *rq = scsi_cmd_to_rq(cmd);
- unsigned int flags = cmd->flags & SCMD_PRESERVED_FLAGS;
- unsigned long jiffies_at_alloc;
- int retries, to_clear;
- bool in_flight;
- int budget_token = cmd->budget_token;
-
- if (!blk_rq_is_passthrough(rq) && !(flags & SCMD_INITIALIZED)) {
- flags |= SCMD_INITIALIZED;
+
+ if (!blk_rq_is_passthrough(rq) && !(cmd->flags & SCMD_INITIALIZED)) {
+ cmd->flags |= SCMD_INITIALIZED;
scsi_initialize_rq(rq);
}
- jiffies_at_alloc = cmd->jiffies_at_alloc;
- retries = cmd->retries;
- in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state);
- /*
- * Zero out the cmd, except for the embedded scsi_request. Only clear
- * the driver-private command data if the LLD does not supply a
- * function to initialize that data.
- */
- to_clear = sizeof(*cmd) - sizeof(cmd->req);
- if (!dev->host->hostt->init_cmd_priv)
- to_clear += dev->host->hostt->cmd_size;
- memset((char *)cmd + sizeof(cmd->req), 0, to_clear);
-
cmd->device = dev;
- cmd->sense_buffer = buf;
- cmd->prot_sdb = prot;
- cmd->flags = flags;
+ cmd->flags &= SCMD_PRESERVED_FLAGS;
INIT_LIST_HEAD(&cmd->eh_entry);
INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
- cmd->jiffies_at_alloc = jiffies_at_alloc;
- cmd->retries = retries;
- if (in_flight)
- __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
- cmd->budget_token = budget_token;
-
}
static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev,
@@ -1586,10 +1558,35 @@ static blk_status_t scsi_prepare_cmd(struct request *req)
struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
struct scsi_device *sdev = req->q->queuedata;
struct Scsi_Host *shost = sdev->host;
+ bool in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state);
struct scatterlist *sg;
scsi_init_command(sdev, cmd);
+ cmd->eh_eflags = 0;
+ cmd->allowed = 0;
+ cmd->prot_type = 0;
+ cmd->prot_flags = 0;
+ cmd->submitter = 0;
+ cmd->cmd_len = 0;
+ cmd->cmnd = NULL;
+ memset(&cmd->sdb, 0, sizeof(cmd->sdb));
+ cmd->underflow = 0;
+ cmd->transfersize = 0;
+ cmd->host_scribble = NULL;
+ cmd->result = 0;
+ cmd->extra_len = 0;
+ cmd->state = 0;
+ if (in_flight)
+ __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
+
+ /*
+ * Only clear the driver-private command data if the LLD does not supply
+ * a function to initialize that data.
+ */
+ if (!shost->hostt->init_cmd_priv)
+ memset(cmd + 1, 0, shost->hostt->cmd_size);
+
cmd->prot_op = SCSI_PROT_NORMAL;
if (blk_rq_bytes(req))
cmd->sc_data_direction = rq_dma_dir(req);
--
2.30.2
