user/sven/linux.git/include/linux/scatterlist.h, branch v6.2.7

lib/scatterlist: add flag for indicating P2PDMA segments in an SGL

2022-07-26T11:27:47Z

Introduce a dma_flags field in struct scatterlist. These flags will be used by dma_[un]map_sg_p2pdma() to determine when a given SGL segments dma_address points to a PCI bus address. dma_unmap_sg_p2pdma() will need to perform different cleanup when a segment is marked as a bus address. The dma_flags field will fit in the existing padding on 64BIT systems (assuming CONFIG_NEED_SG_DMA_LENGTH is also set). The new bit will only be used when CONFIG_PCI_P2PDMA is set; this means PCI P2PDMA will require CONFIG_64BIT. This should be acceptable as the majority of P2PDMA use cases are restricted to newer root complexes and roughly require the extra address space for memory BARs used in the transactions. Signed-off-by: Logan Gunthorpe Signed-off-by: Christoph Hellwig

lib/scatterlist: cleanup macros into static inline functions

2021-12-22T08:21:43Z

Convert the sg_is_chain(), sg_is_last() and sg_chain_ptr() macros into static inline functions. There's no reason for these to be macros and static inline are generally preferred these days. Also introduce the SG_PAGE_LINK_MASK define so the P2PDMA work, which is adding another bit to this mask, can do so more easily. Suggested-by: Jason Gunthorpe Signed-off-by: Logan Gunthorpe Reviewed-by: Chaitanya Kulkarni Signed-off-by: Christoph Hellwig

lib/scatterlist: Fix wrong update of orig_nents

2021-08-24T22:52:40Z

orig_nents should represent the number of entries with pages, but __sg_alloc_table_from_pages sets orig_nents as the number of total entries in the table. This is wrong when the API is used for dynamic allocation where not all the table entries are mapped with pages. It wasn't observed until now, since RDMA umem who uses this API in the dynamic form doesn't use orig_nents implicit or explicit by the scatterlist APIs. Fix it by changing the append API to track the SG append table state and have an API to free the append table according to the total number of entries in the table. Now all APIs set orig_nents as number of enries with pages. Fixes: 07da1223ec93 ("lib/scatterlist: Add support in dynamic allocation of SG table from pages") Link: https://lore.kernel.org/r/20210824142531.3877007-3-maorg@nvidia.com Signed-off-by: Maor Gottlieb Signed-off-by: Leon Romanovsky Signed-off-by: Jason Gunthorpe

lib/scatterlist: Provide a dedicated function to support table append

2021-08-24T18:21:14Z

RDMA is the only in-kernel user that uses __sg_alloc_table_from_pages to append pages dynamically. In the next patch. That mode will be extended and that function will get more parameters. So separate it into a unique function to make such change more clear. Link: https://lore.kernel.org/r/20210824142531.3877007-2-maorg@nvidia.com Signed-off-by: Maor Gottlieb Signed-off-by: Leon Romanovsky Signed-off-by: Jason Gunthorpe

lib: fix spelling mistakes in header files

2021-07-08T18:48:20Z

Fix some spelling mistakes in comments found by "codespell": Hoever ==> However poiter ==> pointer representaion ==> representation uppon ==> upon independend ==> independent aquired ==> acquired mis-match ==> mismatch scrach ==> scratch struture ==> structure Analagous ==> Analogous interation ==> iteration And some were discovered manually by Joe Perches and Christoph Lameter: stroed ==> stored arch independent ==> an architecture independent A example structure for ==> Example structure for Link: https://lkml.kernel.org/r/20210609150027.14805-2-thunder.leizhen@huawei.com Signed-off-by: Zhen Lei Cc: Christoph Lameter Cc: Masami Hiramatsu Cc: Dennis Zhou Cc: Tejun Heo Cc: Joe Perches Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

drm: Remove SCATTERLIST_MAX_SEGMENT

2020-11-02T13:42:57Z

Since commit 9a40401cfa13 ("lib/scatterlist: Do not limit max_segment to PAGE_ALIGNED values") the max_segment input to sg_alloc_table_from_pages() does not have to be any special value. The new algorithm will always create something less than what the user provides. Thus eliminate this confusing constant. - vmwgfx should use the HW capability, not mix in the OS page size for calling dma_set_max_seg_size() - i915 uses i915_sg_segment_size() both for sg_alloc_table_from_pages and for some open coded sgl construction. This doesn't change the value since rounddown(size, UINT_MAX) == SCATTERLIST_MAX_SEGMENT - drm_prime_pages_to_sg uses it as a default if max_segment is zero, UINT_MAX is fine to use directly. Cc: Gerd Hoffmann Cc: Daniel Vetter Cc: Thomas Hellstrom Cc: Qian Cai Cc: "Ursulin, Tvrtko" Suggested-by: Christoph Hellwig Signed-off-by: Jason Gunthorpe Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/0-v1-44733fccd781+13d-rm_scatterlist_max_jgg@nvidia.com

lib/scatterlist: Add support in dynamic allocation of SG table from pages

2020-10-05T23:45:45Z

Extend __sg_alloc_table_from_pages to support dynamic allocation of SG table from pages. It should be used by drivers that can't supply all the pages at one time. This function returns the last populated SGE in the table. Users should pass it as an argument to the function from the second call and forward. As before, nents will be equal to the number of populated SGEs (chunks). With this new extension, drivers can benefit the optimization of merging contiguous pages without a need to allocate all pages in advance and hold them in a large buffer. E.g. with the Infiniband driver that allocates a single page for hold the pages. For 1TB memory registration, the temporary buffer would consume only 4KB, instead of 2GB. Link: https://lore.kernel.org/r/20201004154340.1080481-2-leon@kernel.org Signed-off-by: Maor Gottlieb Reviewed-by: Christoph Hellwig Signed-off-by: Leon Romanovsky Signed-off-by: Jason Gunthorpe

scatterlist: protect parameters of the sg_table related macros

2020-07-06T14:07:25Z

Add brackets to protect parameters of the recently added sg_table related macros from side-effects. Fixes: 709d6d73c756 ("scatterlist: add generic wrappers for iterating over sgtable objects") Signed-off-by: Marek Szyprowski Signed-off-by: Christoph Hellwig

scatterlist: add generic wrappers for iterating over sgtable objects

2020-05-13T13:48:17Z

struct sg_table is a common structure used for describing a memory buffer. It consists of a scatterlist with memory pages and DMA addresses (sgl entry), as well as the number of scatterlist entries: CPU pages (orig_nents entry) and DMA mapped pages (nents entry). It turned out that it was a common mistake to misuse nents and orig_nents entries, calling the scatterlist iterating functions with a wrong number of the entries. To avoid such issues, lets introduce a common wrappers operating directly on the struct sg_table objects, which take care of the proper use of the nents and orig_nents entries. While touching this, lets clarify some ambiguities in the comments for the existing for_each helpers. Signed-off-by: Marek Szyprowski Reviewed-by: Robin Murphy Signed-off-by: Christoph Hellwig

scsi: lib/sg_pool.c: improve APIs for allocating sg pool

2019-06-20T19:21:33Z

sg_alloc_table_chained() currently allows the caller to provide one preallocated SGL and returns if the requested number isn't bigger than size of that SGL. This is used to inline an SGL for an IO request. However, scattergather code only allows that size of the 1st preallocated SGL to be SG_CHUNK_SIZE(128). This means a substantial amount of memory (4KB) is claimed for the SGL for each IO request. If the I/O is small, it would be prudent to allocate a smaller SGL. Introduce an extra parameter to sg_alloc_table_chained() and sg_free_table_chained() for specifying size of the preallocated SGL. Both __sg_free_table() and __sg_alloc_table() assume that each SGL has the same size except for the last one. Change the code to allow both functions to accept a variable size for the 1st preallocated SGL. [mkp: attempted to clarify commit desc] Cc: Christoph Hellwig Cc: Bart Van Assche Cc: Ewan D. Milne Cc: Hannes Reinecke Cc: Sagi Grimberg Cc: Chuck Lever Cc: netdev@vger.kernel.org Cc: linux-nvme@lists.infradead.org Suggested-by: Christoph Hellwig Signed-off-by: Ming Lei Reviewed-by: Christoph Hellwig Signed-off-by: Martin K. Petersen