[PATCH] uml: revert block driver use of host AIO
The patch to use host AIO support that I submitted early after 2.6.13 exposed
some problems in the block driver. I have fixes for these, but am not
comfortable putting them into 2.6.14 at this late date. So, this patch reverts
the use of host AIO.
I will resubmit the original patch, plus fixes to the driver after 2.6.14
in order to get a reasonable amount of testing before they're exposed to
the general public.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/um/os-Linux/aio.c b/arch/um/os-Linux/aio.c
index f6e6402..41cfb09 100644
--- a/arch/um/os-Linux/aio.c
+++ b/arch/um/os-Linux/aio.c
@@ -6,7 +6,6 @@
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
-#include <string.h>
#include <errno.h>
#include <sched.h>
#include <sys/syscall.h>
@@ -17,31 +16,18 @@
#include "user.h"
#include "mode.h"
+struct aio_thread_req {
+ enum aio_type type;
+ int io_fd;
+ unsigned long long offset;
+ char *buf;
+ int len;
+ struct aio_context *aio;
+};
+
static int aio_req_fd_r = -1;
static int aio_req_fd_w = -1;
-static int update_aio(struct aio_context *aio, int res)
-{
- if(res < 0)
- aio->len = res;
- else if((res == 0) && (aio->type == AIO_READ)){
- /* This is the EOF case - we have hit the end of the file
- * and it ends in a partial block, so we fill the end of
- * the block with zeros and claim success.
- */
- memset(aio->data, 0, aio->len);
- aio->len = 0;
- }
- else if(res > 0){
- aio->len -= res;
- aio->data += res;
- aio->offset += res;
- return aio->len;
- }
-
- return 0;
-}
-
#if defined(HAVE_AIO_ABI)
#include <linux/aio_abi.h>
@@ -80,7 +66,8 @@
* that it now backs the mmapped area.
*/
-static int do_aio(aio_context_t ctx, struct aio_context *aio)
+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;
char c;
@@ -88,39 +75,40 @@
iocb = ((struct iocb) { .aio_data = (unsigned long) aio,
.aio_reqprio = 0,
- .aio_fildes = aio->fd,
- .aio_buf = (unsigned long) aio->data,
- .aio_nbytes = aio->len,
- .aio_offset = aio->offset,
+ .aio_fildes = fd,
+ .aio_buf = (unsigned long) buf,
+ .aio_nbytes = len,
+ .aio_offset = offset,
.aio_reserved1 = 0,
.aio_reserved2 = 0,
.aio_reserved3 = 0 });
- switch(aio->type){
+ switch(type){
case AIO_READ:
iocb.aio_lio_opcode = IOCB_CMD_PREAD;
+ err = io_submit(ctx, 1, &iocbp);
break;
case AIO_WRITE:
iocb.aio_lio_opcode = IOCB_CMD_PWRITE;
+ err = io_submit(ctx, 1, &iocbp);
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);
break;
default:
- printk("Bogus op in do_aio - %d\n", aio->type);
+ printk("Bogus op in do_aio - %d\n", type);
err = -EINVAL;
- goto out;
+ break;
}
- err = io_submit(ctx, 1, &iocbp);
if(err > 0)
err = 0;
else
err = -errno;
- out:
return err;
}
@@ -129,9 +117,8 @@
static int aio_thread(void *arg)
{
struct aio_thread_reply reply;
- struct aio_context *aio;
struct io_event event;
- int err, n;
+ int err, n, reply_fd;
signal(SIGWINCH, SIG_IGN);
@@ -144,22 +131,14 @@
"errno = %d\n", errno);
}
else {
- /* This is safe as we've just a pointer here. */
- aio = (struct aio_context *) (long) event.data;
- if(update_aio(aio, event.res)){
- do_aio(ctx, aio);
- continue;
- }
-
reply = ((struct aio_thread_reply)
- { .data = aio,
- .err = aio->len });
- err = os_write_file(aio->reply_fd, &reply,
- sizeof(reply));
+ { .data = (void *) (long) event.data,
+ .err = event.res });
+ reply_fd = ((struct aio_context *) reply.data)->reply_fd;
+ err = os_write_file(reply_fd, &reply, sizeof(reply));
if(err != sizeof(reply))
- printk("aio_thread - write failed, "
- "fd = %d, err = %d\n", aio->reply_fd,
- -err);
+ printk("aio_thread - write failed, fd = %d, "
+ "err = %d\n", aio_req_fd_r, -err);
}
}
return 0;
@@ -167,35 +146,35 @@
#endif
-static int do_not_aio(struct aio_context *aio)
+static int do_not_aio(struct aio_thread_req *req)
{
char c;
int err;
- switch(aio->type){
+ switch(req->type){
case AIO_READ:
- err = os_seek_file(aio->fd, aio->offset);
+ err = os_seek_file(req->io_fd, req->offset);
if(err)
goto out;
- err = os_read_file(aio->fd, aio->data, aio->len);
+ err = os_read_file(req->io_fd, req->buf, req->len);
break;
case AIO_WRITE:
- err = os_seek_file(aio->fd, aio->offset);
+ err = os_seek_file(req->io_fd, req->offset);
if(err)
goto out;
- err = os_write_file(aio->fd, aio->data, aio->len);
+ err = os_write_file(req->io_fd, req->buf, req->len);
break;
case AIO_MMAP:
- err = os_seek_file(aio->fd, aio->offset);
+ err = os_seek_file(req->io_fd, req->offset);
if(err)
goto out;
- err = os_read_file(aio->fd, &c, sizeof(c));
+ err = os_read_file(req->io_fd, &c, sizeof(c));
break;
default:
- printk("do_not_aio - bad request type : %d\n", aio->type);
+ printk("do_not_aio - bad request type : %d\n", req->type);
err = -EINVAL;
break;
}
@@ -206,14 +185,14 @@
static int not_aio_thread(void *arg)
{
- struct aio_context *aio;
+ struct aio_thread_req req;
struct aio_thread_reply reply;
int err;
signal(SIGWINCH, SIG_IGN);
while(1){
- err = os_read_file(aio_req_fd_r, &aio, sizeof(aio));
- if(err != sizeof(aio)){
+ err = os_read_file(aio_req_fd_r, &req, sizeof(req));
+ if(err != sizeof(req)){
if(err < 0)
printk("not_aio_thread - read failed, "
"fd = %d, err = %d\n", aio_req_fd_r,
@@ -224,34 +203,17 @@
}
continue;
}
- again:
- err = do_not_aio(aio);
-
- if(update_aio(aio, err))
- goto again;
-
- reply = ((struct aio_thread_reply) { .data = aio,
- .err = aio->len });
- err = os_write_file(aio->reply_fd, &reply, sizeof(reply));
+ err = do_not_aio(&req);
+ reply = ((struct aio_thread_reply) { .data = req.aio,
+ .err = err });
+ err = os_write_file(req.aio->reply_fd, &reply, sizeof(reply));
if(err != sizeof(reply))
printk("not_aio_thread - write failed, fd = %d, "
"err = %d\n", aio_req_fd_r, -err);
}
}
-static int submit_aio_24(struct aio_context *aio)
-{
- int err;
-
- err = os_write_file(aio_req_fd_w, &aio, sizeof(aio));
- if(err == sizeof(aio))
- err = 0;
-
- return err;
-}
-
static int aio_pid = -1;
-static int (*submit_proc)(struct aio_context *aio);
static int init_aio_24(void)
{
@@ -283,33 +245,11 @@
#endif
printk("2.6 host AIO support not used - falling back to I/O "
"thread\n");
-
- submit_proc = submit_aio_24;
-
return 0;
}
#ifdef HAVE_AIO_ABI
#define DEFAULT_24_AIO 0
-static int submit_aio_26(struct aio_context *aio)
-{
- struct aio_thread_reply reply;
- int err;
-
- err = do_aio(ctx, aio);
- if(err){
- reply = ((struct aio_thread_reply) { .data = aio,
- .err = err });
- err = os_write_file(aio->reply_fd, &reply, sizeof(reply));
- if(err != sizeof(reply))
- printk("submit_aio_26 - write failed, "
- "fd = %d, err = %d\n", aio->reply_fd, -err);
- else err = 0;
- }
-
- return err;
-}
-
static int init_aio_26(void)
{
unsigned long stack;
@@ -330,22 +270,39 @@
aio_pid = err;
printk("Using 2.6 host AIO\n");
-
- submit_proc = submit_aio_26;
-
return 0;
}
+static int submit_aio_26(enum aio_type type, int io_fd, char *buf, int len,
+ unsigned long long offset, struct aio_context *aio)
+{
+ struct aio_thread_reply reply;
+ int err;
+
+ err = do_aio(ctx, type, io_fd, buf, len, offset, aio);
+ if(err){
+ reply = ((struct aio_thread_reply) { .data = aio,
+ .err = err });
+ err = os_write_file(aio->reply_fd, &reply, sizeof(reply));
+ if(err != sizeof(reply))
+ printk("submit_aio_26 - write failed, "
+ "fd = %d, err = %d\n", aio->reply_fd, -err);
+ else err = 0;
+ }
+
+ return err;
+}
+
#else
#define DEFAULT_24_AIO 1
-static int submit_aio_26(struct aio_context *aio)
+static int init_aio_26(void)
{
return -ENOSYS;
}
-static int init_aio_26(void)
+static int submit_aio_26(enum aio_type type, int io_fd, char *buf, int len,
+ unsigned long long offset, struct aio_context *aio)
{
- submit_proc = submit_aio_26;
return -ENOSYS;
}
#endif
@@ -412,7 +369,33 @@
__uml_exitcall(exit_aio);
-int submit_aio(struct aio_context *aio)
+static int submit_aio_24(enum aio_type type, int io_fd, char *buf, int len,
+ unsigned long long offset, struct aio_context *aio)
{
- return (*submit_proc)(aio);
+ struct aio_thread_req req = { .type = type,
+ .io_fd = io_fd,
+ .offset = offset,
+ .buf = buf,
+ .len = len,
+ .aio = aio,
+ };
+ int err;
+
+ err = os_write_file(aio_req_fd_w, &req, sizeof(req));
+ if(err == sizeof(req))
+ err = 0;
+
+ return err;
+}
+
+int submit_aio(enum aio_type type, int io_fd, char *buf, int len,
+ unsigned long long offset, int reply_fd,
+ struct aio_context *aio)
+{
+ aio->reply_fd = reply_fd;
+ if(aio_24)
+ return submit_aio_24(type, io_fd, buf, len, offset, aio);
+ else {
+ return submit_aio_26(type, io_fd, buf, len, offset, aio);
+ }
}