The vfs has long had a write lifetime hint mechanism that gives the
expected longevity on storage of the data being written. f2fs was the
original consumer of this and used the hint for flash data placement
(mostly to avoid write amplification by placing objects with similar
lifetimes in the same erase block). More recently the SCSI based UFS
(Universal Flash Storage) drivers have wanted to take advantage of
this as well, for the same reasons as f2fs, necessitating plumbing the
write hints through the block layer and then adding it to the SCSI
core. The vfs write_hints pull you've already taken plumbs this as
far as block and this pull request completes the SCSI core enabling
based on a recently agreed reuse of the old write command group
number. The additions to the scsi_debug driver are for emulating this
property so we can run tests on it in the absence of an actual UFS
device.
Signed-off-by: James E.J. Bottomley <jejb@linux.ibm.com>
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Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Pull more SCSI updates from James Bottomley:
"The vfs has long had a write lifetime hint mechanism that gives the
expected longevity on storage of the data being written. f2fs was the
original consumer of this and used the hint for flash data placement
(mostly to avoid write amplification by placing objects with similar
lifetimes in the same erase block).
More recently the SCSI based UFS (Universal Flash Storage) drivers
have wanted to take advantage of this as well, for the same reasons as
f2fs, necessitating plumbing the write hints through the block layer
and then adding it to the SCSI core.
The vfs write_hints already taken plumbs this as far as block and this
completes the SCSI core enabling based on a recently agreed reuse of
the old write command group number. The additions to the scsi_debug
driver are for emulating this property so we can run tests on it in
the absence of an actual UFS device"
* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: scsi_debug: Maintain write statistics per group number
scsi: scsi_debug: Implement GET STREAM STATUS
scsi: scsi_debug: Implement the IO Advice Hints Grouping mode page
scsi: scsi_debug: Allocate the MODE SENSE response from the heap
scsi: scsi_debug: Rework subpage code error handling
scsi: scsi_debug: Rework page code error handling
scsi: scsi_debug: Support the block limits extension VPD page
scsi: scsi_debug: Reduce code duplication
scsi: sd: Translate data lifetime information
scsi: scsi_proto: Add structures and constants related to I/O groups and streams
scsi: core: Query the Block Limits Extension VPD page
bfa8f18691