uml: fix aio compilation bug

Restructure do_aio thanks to commments from Ulrich and Al.

Uli started this by seeing that UML's initialization of a struct iocb
initialized fields that it shouldn't.

Al followed up by adding the following cleanups:
	eliminating a variable by just using an anonymous structure in
its place.
	hoisting a duplicated line out of the switch.
	simplifying the error checking at the end.

I added a severity to the printk.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 30 deletions

diff --git a/arch/um/os-Linux/aio.c b/arch/um/os-Linux/aio.c
index b126df4ea168..59348359f9ab 100644
--- a/arch/um/os-Linux/aio.c
+++ b/arch/um/os-Linux/aio.c
@@ -14,6 +14,7 @@
 #include "init.h"
 #include "user.h"
 #include "mode.h"
+#include "kern_constants.h"
 
 struct aio_thread_req {
         enum aio_type type;
@@ -65,47 +66,33 @@ static long io_getevents(aio_context_t ctx_id, long min_nr, long nr,
 static int do_aio(aio_context_t ctx, enum aio_type type, int fd, char *buf,
                   int len, unsigned long long offset, struct aio_context *aio)
 {
-        struct iocb iocb, *iocbp = &iocb;
+        struct iocb *iocbp = & ((struct iocb) {
+                                    .aio_data       = (unsigned long) aio,
+                                    .aio_fildes     = fd,
+                                    .aio_buf        = (unsigned long) buf,
+                                    .aio_nbytes     = len,
+                                    .aio_offset     = offset
+                             });
         char c;
-        int err;
 
-        iocb = ((struct iocb) { .aio_data       = (unsigned long) aio,
-                                .aio_reqprio    = 0,
-                                .aio_fildes     = fd,
-                                .aio_buf        = (unsigned long) buf,
-                                .aio_nbytes     = len,
-                                .aio_offset     = offset,
-                                .aio_reserved1  = 0,
-                                .aio_reserved2  = 0,
-                                .aio_reserved3  = 0 });
-
-        switch(type){
+        switch (type) {
         case AIO_READ:
-                iocb.aio_lio_opcode = IOCB_CMD_PREAD;
-                err = io_submit(ctx, 1, &iocbp);
+                iocbp->aio_lio_opcode = IOCB_CMD_PREAD;
                 break;
         case AIO_WRITE:
-                iocb.aio_lio_opcode = IOCB_CMD_PWRITE;
-                err = io_submit(ctx, 1, &iocbp);
+                iocbp->aio_lio_opcode = IOCB_CMD_PWRITE;
                 break;
         case AIO_MMAP:
-                iocb.aio_lio_opcode = IOCB_CMD_PREAD;
-                iocb.aio_buf = (unsigned long) &c;
-                iocb.aio_nbytes = sizeof(c);
-                err = io_submit(ctx, 1, &iocbp);
+                iocbp->aio_lio_opcode = IOCB_CMD_PREAD;
+                iocbp->aio_buf = (unsigned long) &c;
+                iocbp->aio_nbytes = sizeof(c);
                 break;
         default:
-                printk("Bogus op in do_aio - %d\n", type);
-                err = -EINVAL;
-                break;
+                printk(UM_KERN_ERR "Bogus op in do_aio - %d\n", type);
+                return -EINVAL;
         }
 
-        if(err > 0)
-                err = 0;
-        else
-                err = -errno;
-
-        return err;
+        return (io_submit(ctx, 1, &iocbp) > 0) ? 0 : -errno;
 }
 
 /* Initialized in an initcall and unchanged thereafter */