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io_uring/memmap: unify io_uring mmap'ing code

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All mapped memory is now backed by regions and we can unify and clean
up io_region_validate_mmap() and io_uring_mmap(). Extract a function
looking up a region, the rest of the handling should be generic and just
needs the region.

There is one more ring type specific code, i.e. the mmaping size
truncation quirk for IORING_OFF_[S,C]Q_RING, which is left as is.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/f5e1eda1562bfd34276de07465525ae5f10e1e84.1732886067.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2024-11-29 13:34:39 +00:00 • committed by Jens Axboe
parent ef62de3c4a
commit 7cd7b95752
2 changed files with 31 additions and 53 deletions
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3
io_uring/kbuf.c
View file

@ -748,8 +748,5 @@ struct io_mapped_region *io_pbuf_get_region(struct io_ring_ctx *ctx,
bl = xa_load(&ctx->io_bl_xa, bgid);
if (!bl || !(bl->flags & IOBL_BUF_RING))
return NULL;
if (WARN_ON_ONCE(!io_region_is_set(&bl->region)))
return NULL;
return &bl->region;
}

81
io_uring/memmap.c
View file

@ -254,6 +254,27 @@ int io_create_region_mmap_safe(struct io_ring_ctx *ctx, struct io_mapped_region
return 0;
}
static struct io_mapped_region *io_mmap_get_region(struct io_ring_ctx *ctx,
loff_t pgoff)
{
loff_t offset = pgoff << PAGE_SHIFT;
unsigned int bgid;
switch (offset & IORING_OFF_MMAP_MASK) {
case IORING_OFF_SQ_RING:
case IORING_OFF_CQ_RING:
return &ctx->ring_region;
case IORING_OFF_SQES:
return &ctx->sq_region;
case IORING_OFF_PBUF_RING:
bgid = (offset & ~IORING_OFF_MMAP_MASK) >> IORING_OFF_PBUF_SHIFT;
return io_pbuf_get_region(ctx, bgid);
case IORING_MAP_OFF_PARAM_REGION:
return &ctx->param_region;
}
return NULL;
}
static void *io_region_validate_mmap(struct io_ring_ctx *ctx,
struct io_mapped_region *mr)
{
@ -271,39 +292,12 @@ static void *io_uring_validate_mmap_request(struct file *file, loff_t pgoff,
size_t sz)
{
struct io_ring_ctx *ctx = file->private_data;
loff_t offset = pgoff << PAGE_SHIFT;
struct io_mapped_region *region;
switch ((pgoff << PAGE_SHIFT) & IORING_OFF_MMAP_MASK) {
case IORING_OFF_SQ_RING:
case IORING_OFF_CQ_RING:
/* Don't allow mmap if the ring was setup without it */
if (ctx->flags & IORING_SETUP_NO_MMAP)
return ERR_PTR(-EINVAL);
if (!ctx->rings)
return ERR_PTR(-EFAULT);
return ctx->rings;
case IORING_OFF_SQES:
/* Don't allow mmap if the ring was setup without it */
if (ctx->flags & IORING_SETUP_NO_MMAP)
return ERR_PTR(-EINVAL);
if (!ctx->sq_sqes)
return ERR_PTR(-EFAULT);
return ctx->sq_sqes;
case IORING_OFF_PBUF_RING: {
struct io_mapped_region *region;
unsigned int bgid;
bgid = (offset & ~IORING_OFF_MMAP_MASK) >> IORING_OFF_PBUF_SHIFT;
region = io_pbuf_get_region(ctx, bgid);
if (!region)
return ERR_PTR(-EINVAL);
return io_region_validate_mmap(ctx, region);
}
case IORING_MAP_OFF_PARAM_REGION:
return io_region_validate_mmap(ctx, &ctx->param_region);
}
return ERR_PTR(-EINVAL);
region = io_mmap_get_region(ctx, pgoff);
if (!region)
return ERR_PTR(-EINVAL);
return io_region_validate_mmap(ctx, region);
}
#ifdef CONFIG_MMU
@ -324,7 +318,8 @@ __cold int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
struct io_ring_ctx *ctx = file->private_data;
size_t sz = vma->vm_end - vma->vm_start;
long offset = vma->vm_pgoff << PAGE_SHIFT;
unsigned int page_limit;
unsigned int page_limit = UINT_MAX;
struct io_mapped_region *region;
void *ptr;
guard(mutex)(&ctx->mmap_lock);
@ -337,25 +332,11 @@ __cold int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
case IORING_OFF_SQ_RING:
case IORING_OFF_CQ_RING:
page_limit = (sz + PAGE_SIZE - 1) >> PAGE_SHIFT;
return io_region_mmap(ctx, &ctx->ring_region, vma, page_limit);
case IORING_OFF_SQES:
return io_region_mmap(ctx, &ctx->sq_region, vma, UINT_MAX);
case IORING_OFF_PBUF_RING: {
struct io_mapped_region *region;
unsigned int bgid;
bgid = (offset & ~IORING_OFF_MMAP_MASK) >> IORING_OFF_PBUF_SHIFT;
region = io_pbuf_get_region(ctx, bgid);
if (!region)
return -EINVAL;
return io_region_mmap(ctx, region, vma, UINT_MAX);
}
case IORING_MAP_OFF_PARAM_REGION:
return io_region_mmap(ctx, &ctx->param_region, vma, UINT_MAX);
break;
}
return -EINVAL;
region = io_mmap_get_region(ctx, vma->vm_pgoff);
return io_region_mmap(ctx, region, vma, page_limit);
}
unsigned long io_uring_get_unmapped_area(struct file *filp, unsigned long addr,