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IB/qib: Eliminate divide/mod in converting idx to egr buf pointer

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The context init now saves a shift from rcvegrbufs_perchunk
rcvegrbufs_perchunk_shift using ilog2.   A BUG_ON() protects the
power of 2 assumption.

Signed-off-by: Mike Marciniszyn <mike.marciniszyn@qlogic.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
This commit is contained in:
Mike Marciniszyn 2011-09-23 13:16:39 -04:00 committed by Roland Dreier
parent cc6ea1385b
commit 9e1c0e4325
6 changed files with 18 additions and 5 deletions
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8
drivers/infiniband/hw/qib/qib.h
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@ -171,7 +171,9 @@ struct qib_ctxtdata {
/* how many alloc_pages() chunks in rcvegrbuf_pages */
u32 rcvegrbuf_chunks;
/* how many egrbufs per chunk */
u32 rcvegrbufs_perchunk;
u16 rcvegrbufs_perchunk;
/* ilog2 of above */
u16 rcvegrbufs_perchunk_shift;
/* order for rcvegrbuf_pages */
size_t rcvegrbuf_size;
/* rcvhdrq size (for freeing) */
@ -940,7 +942,9 @@ struct qib_devdata {
/* chip address space used by 4k pio buffers */
u32 align4k;
/* size of each rcvegrbuffer */
u32 rcvegrbufsize;
u16 rcvegrbufsize;
/* log2 of above */
u16 rcvegrbufsize_shift;
/* localbus width (1, 2,4,8,16,32) from config space */
u32 lbus_width;
/* localbus speed in MHz */

6
drivers/infiniband/hw/qib/qib_driver.c
View File

@ -279,10 +279,10 @@ bail:
*/
static inline void *qib_get_egrbuf(const struct qib_ctxtdata *rcd, u32 etail)
{
const u32 chunk = etail / rcd->rcvegrbufs_perchunk;
const u32 idx = etail % rcd->rcvegrbufs_perchunk;
const u32 chunk = etail >> rcd->rcvegrbufs_perchunk_shift;
const u32 idx = etail & ((u32)rcd->rcvegrbufs_perchunk - 1);
return rcd->rcvegrbuf[chunk] + idx * rcd->dd->rcvegrbufsize;
return rcd->rcvegrbuf[chunk] + (idx << rcd->dd->rcvegrbufsize_shift);
}
/*

2
drivers/infiniband/hw/qib/qib_iba6120.c
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@ -3273,6 +3273,8 @@ static int init_6120_variables(struct qib_devdata *dd)
/* we always allocate at least 2048 bytes for eager buffers */
ret = ib_mtu_enum_to_int(qib_ibmtu);
dd->rcvegrbufsize = ret != -1 ? max(ret, 2048) : QIB_DEFAULT_MTU;
BUG_ON(!is_power_of_2(dd->rcvegrbufsize));
dd->rcvegrbufsize_shift = ilog2(dd->rcvegrbufsize);
qib_6120_tidtemplate(dd);

2
drivers/infiniband/hw/qib/qib_iba7220.c
View File

@ -4085,6 +4085,8 @@ static int qib_init_7220_variables(struct qib_devdata *dd)
/* we always allocate at least 2048 bytes for eager buffers */
ret = ib_mtu_enum_to_int(qib_ibmtu);
dd->rcvegrbufsize = ret != -1 ? max(ret, 2048) : QIB_DEFAULT_MTU;
BUG_ON(!is_power_of_2(dd->rcvegrbufsize));
dd->rcvegrbufsize_shift = ilog2(dd->rcvegrbufsize);
qib_7220_tidtemplate(dd);

2
drivers/infiniband/hw/qib/qib_iba7322.c
View File

@ -6205,6 +6205,8 @@ static int qib_init_7322_variables(struct qib_devdata *dd)
/* we always allocate at least 2048 bytes for eager buffers */
dd->rcvegrbufsize = max(mtu, 2048);
BUG_ON(!is_power_of_2(dd->rcvegrbufsize));
dd->rcvegrbufsize_shift = ilog2(dd->rcvegrbufsize);
qib_7322_tidtemplate(dd);

3
drivers/infiniband/hw/qib/qib_init.c
View File

@ -183,6 +183,9 @@ struct qib_ctxtdata *qib_create_ctxtdata(struct qib_pportdata *ppd, u32 ctxt)
rcd->rcvegrbuf_chunks = (rcd->rcvegrcnt +
rcd->rcvegrbufs_perchunk - 1) /
rcd->rcvegrbufs_perchunk;
BUG_ON(!is_power_of_2(rcd->rcvegrbufs_perchunk));
rcd->rcvegrbufs_perchunk_shift =
ilog2(rcd->rcvegrbufs_perchunk);
}
return rcd;
}