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firewire: sbp2: omit Scsi_Host lock from queuecommand 

firewire-sbp2 already takes care for internal serialization where
required (ORB list accesses), and it does not use cmd->serial_number
internally.  Hence it is safe to not grab the shost lock around
queuecommand.

While we are at housekeeping, drop a redundant struct member:
sbp2_command_orb.done is set once in a hot path and dereferenced once in
a hot path.  We can as well dereference sbp2_command_orb.cmd->scsi_done
instead.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
This commit is contained in:
Stefan Richter 2011-04-22 12:21:44 +02:00
parent 6ea9e7bbfc
commit b75ca5ea8e
1 changed files with 6 additions and 14 deletions
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20
drivers/firewire/sbp2.c
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@ -125,9 +125,6 @@ MODULE_PARM_DESC(workarounds, "Work around device bugs (default = 0"
", override internal blacklist = " __stringify(SBP2_WORKAROUND_OVERRIDE)
", or a combination)");
/* I don't know why the SCSI stack doesn't define something like this... */
typedef void (*scsi_done_fn_t)(struct scsi_cmnd *);
static const char sbp2_driver_name[] = "sbp2";
/*
@ -314,7 +311,6 @@ struct sbp2_command_orb {
u8 command_block[SBP2_MAX_CDB_SIZE];
} request;
struct scsi_cmnd *cmd;
scsi_done_fn_t done;
struct sbp2_logical_unit *lu;
struct sbp2_pointer page_table[SG_ALL] __attribute__((aligned(8)));
@ -1398,7 +1394,7 @@ static void complete_command_orb(struct sbp2_orb *base_orb,
sbp2_unmap_scatterlist(device->card->device, orb);
orb->cmd->result = result;
orb->done(orb->cmd);
orb->cmd->scsi_done(orb->cmd);
}
static int sbp2_map_scatterlist(struct sbp2_command_orb *orb,
@ -1463,7 +1459,8 @@ static int sbp2_map_scatterlist(struct sbp2_command_orb *orb,
/* SCSI stack integration */
static int sbp2_scsi_queuecommand_lck(struct scsi_cmnd *cmd, scsi_done_fn_t done)
static int sbp2_scsi_queuecommand(struct Scsi_Host *shost,
struct scsi_cmnd *cmd)
{
struct sbp2_logical_unit *lu = cmd->device->hostdata;
struct fw_device *device = target_device(lu->tgt);
@ -1477,7 +1474,7 @@ static int sbp2_scsi_queuecommand_lck(struct scsi_cmnd *cmd, scsi_done_fn_t done
if (cmd->sc_data_direction == DMA_BIDIRECTIONAL) {
fw_error("Can't handle DMA_BIDIRECTIONAL, rejecting command\n");
cmd->result = DID_ERROR << 16;
done(cmd);
cmd->scsi_done(cmd);
return 0;
}
@ -1490,11 +1487,8 @@ static int sbp2_scsi_queuecommand_lck(struct scsi_cmnd *cmd, scsi_done_fn_t done
/* Initialize rcode to something not RCODE_COMPLETE. */
orb->base.rcode = -1;
kref_init(&orb->base.kref);
orb->lu = lu;
orb->done = done;
orb->cmd = cmd;
orb->lu = lu;
orb->cmd = cmd;
orb->request.next.high = cpu_to_be32(SBP2_ORB_NULL);
orb->request.misc = cpu_to_be32(
COMMAND_ORB_MAX_PAYLOAD(lu->tgt->max_payload) |
@ -1529,8 +1523,6 @@ static int sbp2_scsi_queuecommand_lck(struct scsi_cmnd *cmd, scsi_done_fn_t done
return retval;
}
static DEF_SCSI_QCMD(sbp2_scsi_queuecommand)
static int sbp2_scsi_slave_alloc(struct scsi_device *sdev)
{
struct sbp2_logical_unit *lu = sdev->hostdata;