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io_uring: add mapping support for NOMMU archs

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That is a bit weird scenario but I find it interesting to run fio loads
using LKL linux, where MMU is disabled.  Probably other real archs which
run uClinux can also benefit from this patch.

Signed-off-by: Roman Penyaev <rpenyaev@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Roman Penyaev 2019-11-28 12:53:22 +01:00 committed by Jens Axboe
parent 396bbe1427
commit 6c5c240e41
1 changed files with 51 additions and 6 deletions
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57
fs/io_uring.c
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@ -4402,12 +4402,11 @@ static int io_uring_flush(struct file *file, void *data)
return 0;
}
static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
static void *io_uring_validate_mmap_request(struct file *file,
loff_t pgoff, size_t sz)
{
loff_t offset = (loff_t) vma->vm_pgoff << PAGE_SHIFT;
unsigned long sz = vma->vm_end - vma->vm_start;
struct io_ring_ctx *ctx = file->private_data;
unsigned long pfn;
loff_t offset = pgoff << PAGE_SHIFT;
struct page *page;
void *ptr;
@ -4420,17 +4419,59 @@ static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
ptr = ctx->sq_sqes;
break;
default:
return -EINVAL;
return ERR_PTR(-EINVAL);
}
page = virt_to_head_page(ptr);
if (sz > page_size(page))
return -EINVAL;
return ERR_PTR(-EINVAL);
return ptr;
}
#ifdef CONFIG_MMU
static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
{
size_t sz = vma->vm_end - vma->vm_start;
unsigned long pfn;
void *ptr;
ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz);
if (IS_ERR(ptr))
return PTR_ERR(ptr);
pfn = virt_to_phys(ptr) >> PAGE_SHIFT;
return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot);
}
#else /* !CONFIG_MMU */
static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
{
return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -EINVAL;
}
static unsigned int io_uring_nommu_mmap_capabilities(struct file *file)
{
return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE;
}
static unsigned long io_uring_nommu_get_unmapped_area(struct file *file,
unsigned long addr, unsigned long len,
unsigned long pgoff, unsigned long flags)
{
void *ptr;
ptr = io_uring_validate_mmap_request(file, pgoff, len);
if (IS_ERR(ptr))
return PTR_ERR(ptr);
return (unsigned long) ptr;
}
#endif /* !CONFIG_MMU */
SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
u32, min_complete, u32, flags, const sigset_t __user *, sig,
size_t, sigsz)
@ -4501,6 +4542,10 @@ static const struct file_operations io_uring_fops = {
.release = io_uring_release,
.flush = io_uring_flush,
.mmap = io_uring_mmap,
#ifndef CONFIG_MMU
.get_unmapped_area = io_uring_nommu_get_unmapped_area,
.mmap_capabilities = io_uring_nommu_mmap_capabilities,
#endif
.poll = io_uring_poll,
.fasync = io_uring_fasync,
};