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authorPavel Begunkov <asml.silence@gmail.com>2022-06-25 13:55:38 +0300
committerJens Axboe <axboe@kernel.dk>2022-07-25 03:39:16 +0300
commit6e73dffbb93cb8797cd4e42e98d837edf0f1a967 (patch)
treea1ea7810d2221f23c3bc0f673e6cc6a23262b5c7 /io_uring/filetable.c
parente6130eba8a848a7a6ba6c534bd8f6d60749ae1a9 (diff)
downloadlinux-6e73dffbb93cb8797cd4e42e98d837edf0f1a967.tar.xz
io_uring: let to set a range for file slot allocation
From recently io_uring provides an option to allocate a file index for operation registering fixed files. However, it's utterly unusable with mixed approaches when for a part of files the userspace knows better where to place it, as it may race and users don't have any sane way to pick a slot and hoping it will not be taken. Let the userspace to register a range of fixed file slots in which the auto-allocation happens. The use case is splittting the fixed table in two parts, where on of them is used for auto-allocation and another for slot-specified operations. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/66ab0394e436f38437cf7c44676e1920d09687ad.1656154403.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring/filetable.c')
-rw-r--r--io_uring/filetable.c24
1 files changed, 20 insertions, 4 deletions
diff --git a/io_uring/filetable.c b/io_uring/filetable.c
index abaa5ba7f655..7b473259f3f4 100644
--- a/io_uring/filetable.c
+++ b/io_uring/filetable.c
@@ -16,7 +16,7 @@
static int io_file_bitmap_get(struct io_ring_ctx *ctx)
{
struct io_file_table *table = &ctx->file_table;
- unsigned long nr = ctx->nr_user_files;
+ unsigned long nr = ctx->file_alloc_end;
int ret;
do {
@@ -24,11 +24,10 @@ static int io_file_bitmap_get(struct io_ring_ctx *ctx)
if (ret != nr)
return ret;
- if (!table->alloc_hint)
+ if (table->alloc_hint == ctx->file_alloc_start)
break;
-
nr = table->alloc_hint;
- table->alloc_hint = 0;
+ table->alloc_hint = ctx->file_alloc_start;
} while (1);
return -ENFILE;
@@ -175,3 +174,20 @@ int io_fixed_fd_remove(struct io_ring_ctx *ctx, unsigned int offset)
io_rsrc_node_switch(ctx, ctx->file_data);
return 0;
}
+
+int io_register_file_alloc_range(struct io_ring_ctx *ctx,
+ struct io_uring_file_index_range __user *arg)
+{
+ struct io_uring_file_index_range range;
+ u32 end;
+
+ if (copy_from_user(&range, arg, sizeof(range)))
+ return -EFAULT;
+ if (check_add_overflow(range.off, range.len, &end))
+ return -EOVERFLOW;
+ if (range.resv || end > ctx->nr_user_files)
+ return -EINVAL;
+
+ io_file_table_set_alloc_range(ctx, range.off, range.len);
+ return 0;
+}