On Tue, Sep 27, 2011 at 1:05 PM, Roedel, Joerg <Joerg.Roedel@xxxxxxx> wrote:
> On Fri, Sep 16, 2011 at 01:51:41PM -0400, Ohad Ben-Cohen wrote:
>> int iommu_map(struct iommu_domain *domain, unsigned long iova,
>> - phys_addr_t paddr, int gfp_order, int prot)
>> + phys_addr_t paddr, size_t size, int prot)
>> {
>> - size_t size;
>> + int ret = 0;
>> +
>> + /*
>> + * both the virtual address and the physical one, as well as
>> + * the size of the mapping, must be aligned (at least) to the
>> + * size of the smallest page supported by the hardware
>> + */
>> + if (!IS_ALIGNED(iova | paddr | size, iommu_min_pagesz)) {
>> + pr_err("unaligned: iova 0x%lx pa 0x%lx size 0x%lx min_pagesz "
>> + "0x%x\n", iova, (unsigned long)paddr,
>> + (unsigned long)size, iommu_min_pagesz);
>> + return -EINVAL;
>> + }
>> +
>> + pr_debug("map: iova 0x%lx pa 0x%lx size 0x%lx\n", iova,
>> + (unsigned long)paddr, (unsigned long)size);
>> +
>> + while (size) {
>> + unsigned long pgsize = iommu_min_pagesz;
>> + unsigned long idx = iommu_min_page_idx;
>> + unsigned long addr_merge = iova | paddr;
>> + int order;
>> +
>> + /* find the max page size with which iova, paddr are aligned */
>> + for (;;) {
>> + unsigned long try_pgsize;
>> +
>> + idx = find_next_bit(iommu_pgsize_bitmap,
>> + iommu_nr_page_bits, idx + 1);
>> +
>> + /* no more pages to check ? */
>> + if (idx >= iommu_nr_page_bits)
>> + break;
>> +
>> + try_pgsize = 1 << idx;
>>
>> - size = 0x1000UL << gfp_order;
>> + /* page too big ? addresses not aligned ? */
>> + if (size < try_pgsize ||
>> + !IS_ALIGNED(addr_merge, try_pgsize))
>> + break;
>>
>> - BUG_ON(!IS_ALIGNED(iova | paddr, size));
>> + pgsize = try_pgsize;
>> + }
>
> With an unsigned long you can use plain and fast bit_ops instead of the
> full bitmap functions.
Not sure I follow; the only bit operation I'm using while mapping is
find_next_bit() (which is a bitops.h method).
What other faster variant are you referring to ?
Thanks,
Ohad.
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