From 20e7c3613deaa345003e75eb3578c8a7717e2199 Mon Sep 17 00:00:00 2001 From: William Lee Irwin III Date: Sun, 27 Jun 2004 23:10:38 -0700 Subject: [AIO]: kiocb->private is too large for kiocb's on-stack. sizeof(struct kiocb) is dangerously large for a structure commonly allocated on-stack. This patch converts the 24*sizeof(long) field, ->private, to a void pointer for use by file_operations entrypoints. A ->dtor() method is added to the kiocb in order to support the release of dynamically allocated structures referred to by ->private. The sole in-tree users of ->private are async network read/write, which are not, in fact, async, and so need not handle preallocated ->private as they would need to if ->ki_retry were ever used. The sole truly async operations are direct IO pread()/pwrite() which do not now use ->ki_retry(). All they would need to do in that case is to check for ->private already being allocated for async kiocbs. This rips 88B off the stack on 32-bit in the common case. Signed-off-by: William Lee Irwin III Signed-off-by: David S. Miller --- include/linux/aio.h | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'include/linux') diff --git a/include/linux/aio.h b/include/linux/aio.h index 93fe78800740..461a3b0736e0 100644 --- a/include/linux/aio.h +++ b/include/linux/aio.h @@ -23,8 +23,6 @@ struct kioctx; #define KIOCB_SYNC_KEY (~0U) -#define KIOCB_PRIVATE_SIZE (24 * sizeof(long)) - /* ki_flags bits */ #define KIF_LOCKED 0 #define KIF_KICKED 1 @@ -55,6 +53,7 @@ struct kiocb { struct kioctx *ki_ctx; /* may be NULL for sync ops */ int (*ki_cancel)(struct kiocb *, struct io_event *); long (*ki_retry)(struct kiocb *); + void (*ki_dtor)(struct kiocb *); struct list_head ki_list; /* the aio core uses this * for cancellation */ @@ -65,8 +64,7 @@ struct kiocb { } ki_obj; __u64 ki_user_data; /* user's data for completion */ loff_t ki_pos; - - char private[KIOCB_PRIVATE_SIZE]; + void *private; }; #define is_sync_kiocb(iocb) ((iocb)->ki_key == KIOCB_SYNC_KEY) @@ -79,6 +77,7 @@ struct kiocb { (x)->ki_filp = (filp); \ (x)->ki_ctx = &tsk->active_mm->default_kioctx; \ (x)->ki_cancel = NULL; \ + (x)->ki_dtor = NULL; \ (x)->ki_obj.tsk = tsk; \ } while (0) -- cgit v1.2.3