[AIO] fix sync iocb use of retry mechanism

When the sync infrastructure is used to run a retry using read/write, 
we need to correctly use the buffer offset and byte counts from the 
iocb on subsequent calls to the aio method.

Signed-off-by: Benjamin LaHaise <bcrl@linux.intel.com>
diff -purN --exclude=description 57_intr_cancel/fs/aio.c 59_fix_sync_iocbs/fs/aio.c
--- 57_intr_cancel/fs/aio.c	2005-08-08 17:15:41.000000000 -0400
+++ 59_fix_sync_iocbs/fs/aio.c	2005-08-08 17:15:47.000000000 -0400
@@ -1319,7 +1319,7 @@ asmlinkage long sys_io_destroy(aio_conte
  * Default retry method for aio_read (also used for first time submit)
  * Responsible for updating iocb state as retries progress
  */
-static ssize_t aio_pread(struct kiocb *iocb)
+ssize_t aio_pread(struct kiocb *iocb)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
@@ -1358,7 +1358,7 @@ static ssize_t aio_pread(struct kiocb *i
  * Default retry method for aio_write (also used for first time submit)
  * Responsible for updating iocb state as retries progress
  */
-static ssize_t aio_pwrite(struct kiocb *iocb)
+ssize_t aio_pwrite(struct kiocb *iocb)
 {
 	struct file *file = iocb->ki_filp;
 	ssize_t ret = 0;
diff -purN --exclude=description 57_intr_cancel/fs/read_write.c 59_fix_sync_iocbs/fs/read_write.c
--- 57_intr_cancel/fs/read_write.c	2005-08-08 17:15:45.000000000 -0400
+++ 59_fix_sync_iocbs/fs/read_write.c	2005-08-08 17:15:47.000000000 -0400
@@ -14,6 +14,7 @@
 #include <linux/security.h>
 #include <linux/module.h>
 #include <linux/syscalls.h>
+#include <linux/aio.h>
 
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
@@ -205,7 +206,7 @@ Einval:
 
 static long wait_on_retry_sync_kiocb(struct kiocb *iocb)
 {
-	long (*cancel)(struct kiocb *, struct io_event *);
+	int (*cancel)(struct kiocb *, struct io_event *);
 	long ret = 0;
 	set_current_state(kiocbIsIntr(iocb) ? TASK_INTERRUPTIBLE
 					    : TASK_UNINTERRUPTIBLE);
@@ -217,17 +218,20 @@ static long wait_on_retry_sync_kiocb(str
 	/* If we were interrupted by a signal, issue a cancel to allow the
 	 * operation to clean up.
 	 */
-	cancel = iocb->ki_cancel;
-	if (kiocbIsIntr(iocb) && signal_pending(current) && cancel) {
+	if (kiocbIsIntr(iocb) && signal_pending(current) &&
+	    (cancel = iocb->ki_cancel)) {
 		struct io_event dummy_event;
 		dummy_event.res = 0;
 		if (!cancel(iocb, &dummy_event)) {
 			ret = dummy_event.res;
 			if (!ret)
 				printk(KERN_DEBUG "wait_on_retry_sync_kiocb: ki_cancel method %p is buggy\n", cancel);
+			goto out;
 		}
 	}
 	kiocbClearIntr(iocb);
+	ret = iocb->ki_retry(iocb);
+out:
 	__set_current_state(TASK_RUNNING);
 	return ret;
 }
@@ -239,15 +243,14 @@ ssize_t do_sync_read(struct file *filp, 
 
 	init_sync_kiocb(&kiocb, filp);
 	kiocb.ki_pos = *ppos;
-	while (-EIOCBRETRY == 
-		(ret = filp->f_op->aio_read(&kiocb, buf, len, kiocb.ki_pos))) {
+	kiocb.ki_retry = aio_pread;
+	kiocb.ki_buf = buf;
+	kiocb.ki_nbytes = len;
+	kiocb.ki_left = len;
+	ret = filp->f_op->aio_read(&kiocb, buf, len, *ppos);
+	while (ret == -EIOCBRETRY)
 		ret = wait_on_retry_sync_kiocb(&kiocb);
-		if (ret)
-			break;
-	}
 
-	if (-EIOCBQUEUED == ret)
-		ret = wait_on_sync_kiocb(&kiocb);
 	BUG_ON(!list_empty(&kiocb.ki_wait.task_list));
 	*ppos = kiocb.ki_pos;
 	return ret;
@@ -294,15 +297,14 @@ ssize_t do_sync_write(struct file *filp,
 
 	init_sync_kiocb(&kiocb, filp);
 	kiocb.ki_pos = *ppos;
-	while (-EIOCBRETRY == 
-	       (ret = filp->f_op->aio_write(&kiocb, buf, len, kiocb.ki_pos))) {
+	kiocb.ki_retry = aio_pwrite;
+	kiocb.ki_buf = (void *)buf;
+	kiocb.ki_nbytes = len;
+	kiocb.ki_left = len;
+	ret = filp->f_op->aio_write(&kiocb, buf, len, kiocb.ki_pos);
+	while (ret == -EIOCBRETRY)
 		ret = wait_on_retry_sync_kiocb(&kiocb);
-		if (ret)
-			break;
-	}
 
-	if (-EIOCBQUEUED == ret)
-		ret = wait_on_sync_kiocb(&kiocb);
 	BUG_ON(!list_empty(&kiocb.ki_wait.task_list));
 	*ppos = kiocb.ki_pos;
 	return ret;
diff -purN --exclude=description 57_intr_cancel/include/linux/aio.h 59_fix_sync_iocbs/include/linux/aio.h
--- 57_intr_cancel/include/linux/aio.h	2005-08-08 17:15:42.000000000 -0400
+++ 59_fix_sync_iocbs/include/linux/aio.h	2005-08-08 17:15:47.000000000 -0400
@@ -169,6 +169,8 @@ extern void FASTCALL(exit_aio(struct mm_
 extern struct kioctx *lookup_ioctx(unsigned long ctx_id);
 extern int FASTCALL(io_submit_one(struct kioctx *ctx,
 			struct iocb __user *user_iocb, struct iocb *iocb));
+extern ssize_t aio_pread(struct kiocb *iocb);
+extern ssize_t aio_pwrite(struct kiocb *iocb);
 
 /* semi private, but used by the 32bit emulations: */
 struct kioctx *lookup_ioctx(unsigned long ctx_id);