This updates the ppc iommu/pci dma mappers to sg chaining. Includes
further fixes from FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
The dma mapping helpers need to be converted to using
sg helpers as well, so they will work with a chained
sglist setup.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Otherwise we could have junk in the sg fields, fooling
the sg chaining into thinking ->page is valid.
Acked-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
LIBATA_MAX_PRD is the maximum number of DMA scatter/gather elements
permitted by the HBA's DMA engine. It's properly set to
q->max_hw_segments via the sg_tablesize parameter.
libata shouldn't call blk_queue_max_phys_segments. Now LIBATA_MAX_PRD
is equal to SCSI_MAX_PHYS_SEGMENTS by default (both is 128), so
everything is fine. But if they are changed, some code (like the scsi
mid layer, sg chaining, etc) might not work properly.
(Addition from Jens) The basic issue is that the physical segment
setting is purely a driver issue. And since SCSI is managing the sglist,
libata has no business changing the setting. All libata should care
about is the hw segment setting.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This reverts sg segment size ifdefs that the current code has in order
to provide a way to reduce sgpool memory consumption.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This option is true if a low-level driver can support sg
chaining. This will be removed eventually when all the drivers are
converted to support sg chaining. q->max_phys_segments is set to
SCSI_MAX_SG_SEGMENTS if false.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
ips properly uses scsi_for_each_sg for the normal I/O path, however,
the breakup path doesn't.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
[PATCH] USB storage: sg chaining support
Modify usb_stor_access_xfer_buf() to take a pointer to an sg
entry pointer, so we can keep track of that instead of passing
around an integer index (which we can't use when dealing with
multiple scatterlist arrays).
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This converts libata to using the sg helpers for looking up sg
elements, instead of doing it manually.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This is what enables large commands. If we need to allocate an
sgtable that doesn't fit in a single page, allocate several
SCSI_MAX_SG_SEGMENTS sized tables and chain them together.
SCSI defaults to large chained sg tables, if the arch supports it.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Just pass in the command, no point in passing in the scatterlist
and scatterlist pool index seperately.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Expose this setting for now, so that users can play with enabling
large commands without defaulting it to on globally. This is a debug
patch, it will be dropped for the final versions.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
The core of the patch - allow the last sg element in a scatterlist
table to point to the start of a new table. We overload the LSB of
the page pointer to indicate whether this is a valid sg entry, or
merely a link to the next list.
Includes a fix from Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
correcting the ifdef ARCH_HAS_SG_CHAIN guarding sg_last().
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This converts the SCSI mid layer to using the sg helpers for looking up
sg elements, instead of doing it manually.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This implements functionality to pass down or insert a barrier
in a queue, without having data attached to it. The ->prepare_flush_fn()
infrastructure from data barriers are reused to provide this
functionality.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
End of device check is done twice in __generic_make_request() and it's
fully inlined each time. Factor out bio_check_eod().
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
