# HG changeset patch
# User Ian Campbell <ian.campbell@xxxxxxxxxxxxx>
# Date 1180947923 -3600
# Node ID 4763065c587cb72db94f34670803cc9ad0e3041c
# Parent 405dae994591a785c16c59e50658bea7814b7000
Imported patch blktap-aio-16_03_06.patch from xen-unstable.hg 15200:bd3d6b4c52ec
---
fs/aio.c | 119 ++++++++++++++++++++++++++++++++++++++++++----
fs/eventpoll.c | 18 +++---
include/linux/aio.h | 5 +
include/linux/eventpoll.h | 6 ++
4 files changed, 129 insertions(+), 19 deletions(-)
diff -r 405dae994591 -r 4763065c587c fs/aio.c
--- a/fs/aio.c Mon Jun 04 10:05:23 2007 +0100
+++ b/fs/aio.c Mon Jun 04 10:05:23 2007 +0100
@@ -33,6 +33,11 @@
#include <asm/kmap_types.h>
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
+
+#ifdef CONFIG_EPOLL
+#include <linux/poll.h>
+#include <linux/eventpoll.h>
+#endif
#if DEBUG > 1
#define dprintk printk
@@ -1015,6 +1020,10 @@ put_rq:
if (waitqueue_active(&ctx->wait))
wake_up(&ctx->wait);
+#ifdef CONFIG_EPOLL
+ if (ctx->file && waitqueue_active(&ctx->poll_wait))
+ wake_up(&ctx->poll_wait);
+#endif
if (ret)
put_ioctx(ctx);
@@ -1024,6 +1033,8 @@ put_rq:
/* aio_read_evt
* Pull an event off of the ioctx's event ring. Returns the number of
* events fetched (0 or 1 ;-)
+ * If ent parameter is 0, just returns the number of events that would
+ * be fetched.
* FIXME: make this use cmpxchg.
* TODO: make the ringbuffer user mmap()able (requires FIXME).
*/
@@ -1046,13 +1057,18 @@ static int aio_read_evt(struct kioctx *i
head = ring->head % info->nr;
if (head != ring->tail) {
- struct io_event *evp = aio_ring_event(info, head, KM_USER1);
- *ent = *evp;
- head = (head + 1) % info->nr;
- smp_mb(); /* finish reading the event before updatng the head */
- ring->head = head;
- ret = 1;
- put_aio_ring_event(evp, KM_USER1);
+ if (ent) { /* event requested */
+ struct io_event *evp =
+ aio_ring_event(info, head, KM_USER1);
+ *ent = *evp;
+ head = (head + 1) % info->nr;
+ /* finish reading the event before updatng the head */
+ smp_mb();
+ ring->head = head;
+ ret = 1;
+ put_aio_ring_event(evp, KM_USER1);
+ } else /* only need to know availability */
+ ret = 1;
}
spin_unlock(&info->ring_lock);
@@ -1235,8 +1251,77 @@ static void io_destroy(struct kioctx *io
aio_cancel_all(ioctx);
wait_for_all_aios(ioctx);
+#ifdef CONFIG_EPOLL
+ /* forget the poll file, but it's up to the user to close it */
+ if (ioctx->file) {
+ ioctx->file->private_data = 0;
+ ioctx->file = 0;
+ }
+#endif
put_ioctx(ioctx); /* once for the lookup */
}
+
+#ifdef CONFIG_EPOLL
+
+static int aio_queue_fd_close(struct inode *inode, struct file *file)
+{
+ struct kioctx *ioctx = file->private_data;
+ if (ioctx) {
+ file->private_data = 0;
+ spin_lock_irq(&ioctx->ctx_lock);
+ ioctx->file = 0;
+ spin_unlock_irq(&ioctx->ctx_lock);
+ }
+ return 0;
+}
+
+static unsigned int aio_queue_fd_poll(struct file *file, poll_table *wait)
+{ unsigned int pollflags = 0;
+ struct kioctx *ioctx = file->private_data;
+
+ if (ioctx) {
+
+ spin_lock_irq(&ioctx->ctx_lock);
+ /* Insert inside our poll wait queue */
+ poll_wait(file, &ioctx->poll_wait, wait);
+
+ /* Check our condition */
+ if (aio_read_evt(ioctx, 0))
+ pollflags = POLLIN | POLLRDNORM;
+ spin_unlock_irq(&ioctx->ctx_lock);
+ }
+
+ return pollflags;
+}
+
+static const struct file_operations aioq_fops = {
+ .release = aio_queue_fd_close,
+ .poll = aio_queue_fd_poll
+};
+
+/* make_aio_fd:
+ * Create a file descriptor that can be used to poll the event queue.
+ * Based and piggybacked on the excellent epoll code.
+ */
+
+static int make_aio_fd(struct kioctx *ioctx)
+{
+ int error, fd;
+ struct inode *inode;
+ struct file *file;
+
+ error = ep_getfd(&fd, &inode, &file, NULL, &aioq_fops);
+ if (error)
+ return error;
+
+ /* associate the file with the IO context */
+ file->private_data = ioctx;
+ ioctx->file = file;
+ init_waitqueue_head(&ioctx->poll_wait);
+ return fd;
+}
+#endif
+
/* sys_io_setup:
* Create an aio_context capable of receiving at least nr_events.
@@ -1250,18 +1335,30 @@ static void io_destroy(struct kioctx *io
* resources are available. May fail with -EFAULT if an invalid
* pointer is passed for ctxp. Will fail with -ENOSYS if not
* implemented.
+ *
+ * To request a selectable fd, the user context has to be initialized
+ * to 1, instead of 0, and the return value is the fd.
+ * This keeps the system call compatible, since a non-zero value
+ * was not allowed so far.
*/
asmlinkage long sys_io_setup(unsigned nr_events, aio_context_t __user *ctxp)
{
struct kioctx *ioctx = NULL;
unsigned long ctx;
long ret;
+ int make_fd = 0;
ret = get_user(ctx, ctxp);
if (unlikely(ret))
goto out;
ret = -EINVAL;
+#ifdef CONFIG_EPOLL
+ if (ctx == 1) {
+ make_fd = 1;
+ ctx = 0;
+ }
+#endif
if (unlikely(ctx || nr_events == 0)) {
pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n",
ctx, nr_events);
@@ -1272,8 +1369,12 @@ asmlinkage long sys_io_setup(unsigned nr
ret = PTR_ERR(ioctx);
if (!IS_ERR(ioctx)) {
ret = put_user(ioctx->user_id, ctxp);
- if (!ret)
- return 0;
+#ifdef CONFIG_EPOLL
+ if (make_fd && ret >= 0)
+ ret = make_aio_fd(ioctx);
+#endif
+ if (ret >= 0)
+ return ret;
get_ioctx(ioctx); /* io_destroy() expects us to hold a ref */
io_destroy(ioctx);
diff -r 405dae994591 -r 4763065c587c fs/eventpoll.c
--- a/fs/eventpoll.c Mon Jun 04 10:05:23 2007 +0100
+++ b/fs/eventpoll.c Mon Jun 04 10:05:23 2007 +0100
@@ -236,8 +236,6 @@ struct ep_pqueue {
static void ep_poll_safewake_init(struct poll_safewake *psw);
static void ep_poll_safewake(struct poll_safewake *psw, wait_queue_head_t *wq);
-static int ep_getfd(int *efd, struct inode **einode, struct file **efile,
- struct eventpoll *ep);
static int ep_alloc(struct eventpoll **pep);
static void ep_free(struct eventpoll *ep);
static struct epitem *ep_find(struct eventpoll *ep, struct file *file, int fd);
@@ -267,7 +265,7 @@ static int ep_poll(struct eventpoll *ep,
static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
int maxevents, long timeout);
static int eventpollfs_delete_dentry(struct dentry *dentry);
-static struct inode *ep_eventpoll_inode(void);
+static struct inode *ep_eventpoll_inode(const struct file_operations *fops);
static int eventpollfs_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name,
void *data, struct vfsmount *mnt);
@@ -517,7 +515,7 @@ asmlinkage long sys_epoll_create(int siz
* Creates all the items needed to setup an eventpoll file. That is,
* a file structure, and inode and a free file descriptor.
*/
- error = ep_getfd(&fd, &inode, &file, ep);
+ error = ep_getfd(&fd, &inode, &file, ep, &eventpoll_fops);
if (error)
goto eexit_2;
@@ -702,8 +700,8 @@ eexit_1:
/*
* Creates the file descriptor to be used by the epoll interface.
*/
-static int ep_getfd(int *efd, struct inode **einode, struct file **efile,
- struct eventpoll *ep)
+int ep_getfd(int *efd, struct inode **einode, struct file **efile,
+ struct eventpoll *ep, const struct file_operations *fops)
{
struct qstr this;
char name[32];
@@ -719,7 +717,7 @@ static int ep_getfd(int *efd, struct ino
goto eexit_1;
/* Allocates an inode from the eventpoll file system */
- inode = ep_eventpoll_inode();
+ inode = ep_eventpoll_inode(fops);
error = PTR_ERR(inode);
if (IS_ERR(inode))
goto eexit_2;
@@ -750,7 +748,7 @@ static int ep_getfd(int *efd, struct ino
file->f_pos = 0;
file->f_flags = O_RDONLY;
- file->f_op = &eventpoll_fops;
+ file->f_op = fops;
file->f_mode = FMODE_READ;
file->f_version = 0;
file->private_data = ep;
@@ -1569,7 +1567,7 @@ static int eventpollfs_delete_dentry(str
}
-static struct inode *ep_eventpoll_inode(void)
+static struct inode *ep_eventpoll_inode(const struct file_operations *fops)
{
int error = -ENOMEM;
struct inode *inode = new_inode(eventpoll_mnt->mnt_sb);
@@ -1577,7 +1575,7 @@ static struct inode *ep_eventpoll_inode(
if (!inode)
goto eexit_1;
- inode->i_fop = &eventpoll_fops;
+ inode->i_fop = fops;
/*
* Mark the inode dirty from the very beginning,
diff -r 405dae994591 -r 4763065c587c include/linux/aio.h
--- a/include/linux/aio.h Mon Jun 04 10:05:23 2007 +0100
+++ b/include/linux/aio.h Mon Jun 04 10:05:23 2007 +0100
@@ -191,6 +191,11 @@ struct kioctx {
struct aio_ring_info ring_info;
struct work_struct wq;
+#ifdef CONFIG_EPOLL
+ // poll integration
+ wait_queue_head_t poll_wait;
+ struct file *file;
+#endif
};
/* prototypes */
diff -r 405dae994591 -r 4763065c587c include/linux/eventpoll.h
--- a/include/linux/eventpoll.h Mon Jun 04 10:05:23 2007 +0100
+++ b/include/linux/eventpoll.h Mon Jun 04 10:05:23 2007 +0100
@@ -90,6 +90,12 @@ static inline void eventpoll_release(str
eventpoll_release_file(file);
}
+/*
+ * called by aio code to create fd that can poll the aio event queueQ
+ */
+struct eventpoll;
+int ep_getfd(int *efd, struct inode **einode, struct file **efile,
+ struct eventpoll *ep, const struct file_operations *fops);
#else
static inline void eventpoll_init_file(struct file *file) {}
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