diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/scatterlist.c | 31 |
1 files changed, 20 insertions, 11 deletions
diff --git a/lib/scatterlist.c b/lib/scatterlist.c index dee0c5004e2f..7b2e74da2c44 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -394,17 +394,22 @@ int sg_alloc_table_from_pages(struct sg_table *sgt, unsigned int offset, unsigned long size, gfp_t gfp_mask) { - unsigned int chunks; - unsigned int i; - unsigned int cur_page; + const unsigned int max_segment = SCATTERLIST_MAX_SEGMENT; + unsigned int chunks, cur_page, seg_len, i; int ret; struct scatterlist *s; /* compute number of contiguous chunks */ chunks = 1; - for (i = 1; i < n_pages; ++i) - if (page_to_pfn(pages[i]) != page_to_pfn(pages[i - 1]) + 1) - ++chunks; + seg_len = 0; + for (i = 1; i < n_pages; i++) { + seg_len += PAGE_SIZE; + if (seg_len >= max_segment || + page_to_pfn(pages[i]) != page_to_pfn(pages[i - 1]) + 1) { + chunks++; + seg_len = 0; + } + } ret = sg_alloc_table(sgt, chunks, gfp_mask); if (unlikely(ret)) @@ -413,17 +418,21 @@ int sg_alloc_table_from_pages(struct sg_table *sgt, /* merging chunks and putting them into the scatterlist */ cur_page = 0; for_each_sg(sgt->sgl, s, sgt->orig_nents, i) { - unsigned long chunk_size; - unsigned int j; + unsigned int j, chunk_size; /* look for the end of the current chunk */ - for (j = cur_page + 1; j < n_pages; ++j) - if (page_to_pfn(pages[j]) != + seg_len = 0; + for (j = cur_page + 1; j < n_pages; j++) { + seg_len += PAGE_SIZE; + if (seg_len >= max_segment || + page_to_pfn(pages[j]) != page_to_pfn(pages[j - 1]) + 1) break; + } chunk_size = ((j - cur_page) << PAGE_SHIFT) - offset; - sg_set_page(s, pages[cur_page], min(size, chunk_size), offset); + sg_set_page(s, pages[cur_page], + min_t(unsigned long, size, chunk_size), offset); size -= chunk_size; offset = 0; cur_page = j; |