io_uring: deduplicate file table slot calculation

Extract a helper io_fixed_file_slot() returning a place in our fixed
files table, so we don't hand-code it three times in the code.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 24cc00f..5ee6a92 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7740,6 +7740,15 @@ static void io_rsrc_put_work(struct work_struct *work)
        }
 }
 
+static struct file **io_fixed_file_slot(struct fixed_rsrc_data *file_data,
+                                       unsigned i)
+{
+       struct fixed_rsrc_table *table;
+
+       table = &file_data->table[i >> IORING_FILE_TABLE_SHIFT];
+       return &table->files[i & IORING_FILE_TABLE_MASK];
+}
+
 static void io_rsrc_node_ref_zero(struct percpu_ref *ref)
 {
        struct fixed_rsrc_ref_node *ref_node;
@@ -7808,6 +7817,7 @@ static void destroy_fixed_rsrc_ref_node(struct fixed_rsrc_ref_node *ref_node)
        kfree(ref_node);
 }
 
+
 static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
                                 unsigned nr_args)
 {
@@ -7840,9 +7850,6 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
                goto out_free;
 
        for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
-               struct fixed_rsrc_table *table;
-               unsigned index;
-
                if (copy_from_user(&fd, &fds[i], sizeof(fd))) {
                        ret = -EFAULT;
                        goto out_fput;
@@ -7867,9 +7874,7 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
                        fput(file);
                        goto out_fput;
                }
-               table = &file_data->table[i >> IORING_FILE_TABLE_SHIFT];
-               index = i & IORING_FILE_TABLE_MASK;
-               table->files[index] = file;
+               *io_fixed_file_slot(file_data, i) = file;
        }
 
        ret = io_sqe_files_scm(ctx);
@@ -7972,7 +7977,7 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
 {
        struct fixed_rsrc_data *data = ctx->file_data;
        struct fixed_rsrc_ref_node *ref_node;
-       struct file *file;
+       struct file *file, **file_slot;
        __s32 __user *fds;
        int fd, i, err;
        __u32 done;
@@ -7990,9 +7995,6 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
 
        fds = u64_to_user_ptr(up->data);
        for (done = 0; done < nr_args; done++) {
-               struct fixed_rsrc_table *table;
-               unsigned index;
-
                err = 0;
                if (copy_from_user(&fd, &fds[done], sizeof(fd))) {
                        err = -EFAULT;
@@ -8002,14 +8004,13 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
                        continue;
 
                i = array_index_nospec(up->offset + done, ctx->nr_user_files);
-               table = &ctx->file_data->table[i >> IORING_FILE_TABLE_SHIFT];
-               index = i & IORING_FILE_TABLE_MASK;
-               if (table->files[index]) {
-                       file = table->files[index];
-                       err = io_queue_file_removal(data, file);
+               file_slot = io_fixed_file_slot(ctx->file_data, i);
+
+               if (*file_slot) {
+                       err = io_queue_file_removal(data, *file_slot);
                        if (err)
                                break;
-                       table->files[index] = NULL;
+                       *file_slot = NULL;
                        needs_switch = true;
                }
                if (fd != -1) {
@@ -8031,13 +8032,12 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
                                err = -EBADF;
                                break;
                        }
-                       table->files[index] = file;
                        err = io_sqe_file_register(ctx, file, i);
                        if (err) {
-                               table->files[index] = NULL;
                                fput(file);
                                break;
                        }
+                       *file_slot = file;
                }
        }
 
@@ -9488,11 +9488,8 @@ static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m)
        seq_printf(m, "SqThreadCpu:\t%d\n", sq ? task_cpu(sq->thread) : -1);
        seq_printf(m, "UserFiles:\t%u\n", ctx->nr_user_files);
        for (i = 0; has_lock && i < ctx->nr_user_files; i++) {
-               struct fixed_rsrc_table *table;
-               struct file *f;
+               struct file *f = *io_fixed_file_slot(ctx->file_data, i);
 
-               table = &ctx->file_data->table[i >> IORING_FILE_TABLE_SHIFT];
-               f = table->files[i & IORING_FILE_TABLE_MASK];
                if (f)
                        seq_printf(m, "%5u: %s\n", i, file_dentry(f)->d_iname);
                else