[PATCH 0/4] scatterlist: add new capabilities

From: Douglas Gilbert
Date: Fri Oct 16 2020 - 00:53:24 EST


Scatter-gather lists (sgl_s) are frequently used as data
carriers in the block layer. For example the SCSI and NVMe
subsystems interchange data with the block layer using
sgl_s. The sgl API is declared in <linux/scatterlist.h>

The author has extended these transient sgl use cases to
a store (i.e. ramdisk) in the scsi_debug driver. Other new
potential uses of sgl_s could be for caches. When this extra
step is taken, the need to copy between sgl_s becomes apparent.
The patchset adds sgl_copy_sgl() and a few other sgl
operations.

The existing sgl_alloc_order() function can be seen as a
replacement for vmalloc() for large, long-term allocations.
For what seems like no good reason, sgl_alloc_order()
currently restricts its total allocation to less than or
equal to 4 GiB. vmalloc() has no such restriction.

This patchset is against lk 5.9.0

Douglas Gilbert (4):
sgl_alloc_order: remove 4 GiB limit, sgl_free() warning
scatterlist: add sgl_copy_sgl() function
scatterlist: add sgl_compare_sgl() function
scatterlist: add sgl_memset()

include/linux/scatterlist.h | 12 +++
lib/scatterlist.c | 204 +++++++++++++++++++++++++++++++++++-
2 files changed, 213 insertions(+), 3 deletions(-)

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2.25.1