d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

ioat(4): Add ioat_acquire_reserve() KPI

Browse Source 
ioat_acquire_reserve() is an extended version of ioat_acquire().  It
allows users to reserve space in the channel for some number of
descriptors.  If this succeeds, it guarantees that at least submission
of N valid descriptors will succeed.

Sponsored by:	EMC / Isilon Storage Division
This commit is contained in:
Conrad Meyer 2016-01-07 23:02:15 +00:00
parent eb581ab54a
commit 1502e36346
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=293390
3 changed files with 40 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
share/man/man4/ioat.4
View File

@ -24,7 +24,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd January 5, 2016
.Dd January 7, 2016
.Dt IOAT 4
.Os
.Sh NAME
@ -73,6 +73,8 @@ In
.Fn ioat_get_max_coalesce_period "bus_dmaengine_t dmaengine"
.Ft void
.Fn ioat_acquire "bus_dmaengine_t dmaengine"
.Ft int
.Fn ioat_acquire_reserve "bus_dmaengine_t dmaengine" "uint32_t n" "int mflags"
.Ft void
.Fn ioat_release "bus_dmaengine_t dmaengine"
.Ft struct bus_dmadesc *
@ -178,6 +180,14 @@ When the user wants to offload a copy, they will first
the
.Ar bus_dmaengine_t
object for exclusive access to enqueue operations on that channel.
Optionally, the user can reserve space by using
.Fn ioat_acquire_reserve
instead.
If
.Fn ioat_acquire_reserve
succeeds, there is guaranteed to be room for
.Fa N
new operations in the internal ring buffer.
Then, they will submit one or more operations using
.Fn ioat_blockfill ,
.Fn ioat_copy ,

15
sys/dev/ioat/ioat.c
View File

@ -789,6 +789,21 @@ ioat_acquire(bus_dmaengine_t dmaengine)
CTR0(KTR_IOAT, __func__);
}
int
ioat_acquire_reserve(bus_dmaengine_t dmaengine, unsigned n, int mflags)
{
struct ioat_softc *ioat;
int error;
ioat = to_ioat_softc(dmaengine);
ioat_acquire(dmaengine);
error = ioat_reserve_space(ioat, n, mflags);
if (error != 0)
ioat_release(dmaengine);
return (error);
}
void
ioat_release(bus_dmaengine_t dmaengine)
{

15
sys/dev/ioat/ioat.h
View File

@ -96,12 +96,25 @@ uint16_t ioat_get_max_coalesce_period(bus_dmaengine_t dmaengine);
/*
* Acquire must be called before issuing an operation to perform. Release is
* called after. Multiple operations can be issued within the context of one
* called after. Multiple operations can be issued within the context of one
* acquire and release
*/
void ioat_acquire(bus_dmaengine_t dmaengine);
void ioat_release(bus_dmaengine_t dmaengine);
/*
* Acquire_reserve can be called to ensure there is room for N descriptors. If
* it succeeds, the next N valid operations will successfully enqueue.
*
* It may fail with:
* - ENXIO if the channel is in an errored state, or the driver is being
* unloaded
* - EAGAIN if mflags included M_NOWAIT
*
* On failure, the caller does not hold the dmaengine.
*/
int ioat_acquire_reserve(bus_dmaengine_t dmaengine, unsigned n, int mflags);
/*
* Issue a blockfill operation. The 64-bit pattern 'fillpattern' is written to
* 'len' physically contiguous bytes at 'dst'.