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Closer examination shows that nvme and CAM both normally zero-fill

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allocations (for req and ccb, which ultimately contain the
nvme_cmd). As such, we can micro-optimize these routines. Add a
comment to this effect, and bzero the ccb used to make the requests
for the nda dump rotuine so it more closely matches a ccb allocated
with xpt_get_ccb().

Sponsored by: Netflix
This commit is contained in:
Warner Losh 2017-10-15 23:53:55 +00:00
parent 57ef3db3a9
commit fa271a5d09
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=324644
2 changed files with 8 additions and 8 deletions
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2
sys/cam/nvme/nvme_da.c
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@ -398,6 +398,8 @@ ndadump(void *arg, void *virtual, vm_offset_t physical, off_t offset, size_t len
return (ENXIO);
}
/* xpt_get_ccb returns a zero'd allocation for the ccb, mimic that here */
memset(&nvmeio, 0, sizeof(nvmeio));
if (length > 0) {
xpt_setup_ccb(&nvmeio.ccb_h, periph->path, CAM_PRIORITY_NORMAL);
nvmeio.ccb_h.ccb_state = NDA_CCB_DUMP;

14
sys/dev/nvme/nvme.h
View File

@ -1068,7 +1068,12 @@ uint32_t nvme_ns_get_stripesize(struct nvme_namespace *ns);
int nvme_ns_bio_process(struct nvme_namespace *ns, struct bio *bp,
nvme_cb_fn_t cb_fn);
/* Command building helper functions -- shared with CAM */
/*
* Command building helper functions -- shared with CAM
* These functions assume allocator zeros out cmd structure
* CAM's xpt_get_ccb and the request allocator for nvme both
* do zero'd allocations.
*/
static inline
void nvme_ns_flush_cmd(struct nvme_command *cmd, uint32_t nsid)
{
@ -1082,17 +1087,10 @@ void nvme_ns_rw_cmd(struct nvme_command *cmd, uint32_t rwcmd, uint32_t nsid,
uint64_t lba, uint32_t count)
{
cmd->opc = rwcmd;
cmd->fuse = 0;
cmd->rsvd1 = 0;
cmd->nsid = nsid;
cmd->rsvd2 = 0;
cmd->rsvd3 = 0;
cmd->cdw10 = lba & 0xffffffffu;
cmd->cdw11 = lba >> 32;
cmd->cdw12 = count-1;
cmd->cdw13 = 0;
cmd->cdw14 = 0;
cmd->cdw15 = 0;
}
static inline