diff options
author | Ingo Molnar <mingo@elte.hu> | 2008-07-25 11:37:07 +0200 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-07-25 11:37:07 +0200 |
commit | 0e2f65ee30eee2db054f7fd73f462c5da33ec963 (patch) | |
tree | 26c61eb7745da0c0d9135e9d12088f570cb8530d /include/linux/scatterlist.h | |
parent | da7878d75b8520c9ae00d27dfbbce546a7bfdfbb (diff) | |
parent | fb2e405fc1fc8b20d9c78eaa1c7fd5a297efde43 (diff) |
Merge branch 'linus' into x86/pebs
Conflicts:
arch/x86/Kconfig.cpu
arch/x86/kernel/cpu/intel.c
arch/x86/kernel/setup_64.c
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/linux/scatterlist.h')
-rw-r--r-- | include/linux/scatterlist.h | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index 71fc8136004..e5996984ddd 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -224,4 +224,42 @@ size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents, */ #define SG_MAX_SINGLE_ALLOC (PAGE_SIZE / sizeof(struct scatterlist)) + +/* + * Mapping sg iterator + * + * Iterates over sg entries mapping page-by-page. On each successful + * iteration, @miter->page points to the mapped page and + * @miter->length bytes of data can be accessed at @miter->addr. As + * long as an interation is enclosed between start and stop, the user + * is free to choose control structure and when to stop. + * + * @miter->consumed is set to @miter->length on each iteration. It + * can be adjusted if the user can't consume all the bytes in one go. + * Also, a stopped iteration can be resumed by calling next on it. + * This is useful when iteration needs to release all resources and + * continue later (e.g. at the next interrupt). + */ + +#define SG_MITER_ATOMIC (1 << 0) /* use kmap_atomic */ + +struct sg_mapping_iter { + /* the following three fields can be accessed directly */ + struct page *page; /* currently mapped page */ + void *addr; /* pointer to the mapped area */ + size_t length; /* length of the mapped area */ + size_t consumed; /* number of consumed bytes */ + + /* these are internal states, keep away */ + struct scatterlist *__sg; /* current entry */ + unsigned int __nents; /* nr of remaining entries */ + unsigned int __offset; /* offset within sg */ + unsigned int __flags; +}; + +void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl, + unsigned int nents, unsigned int flags); +bool sg_miter_next(struct sg_mapping_iter *miter); +void sg_miter_stop(struct sg_mapping_iter *miter); + #endif /* _LINUX_SCATTERLIST_H */ |