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(-) -- 2.25.1
